tag:theconversation.com,2011:/global/topics/smoke-3299/articlesSmoke – The Conversation2023-11-13T21:21:44Ztag:theconversation.com,2011:article/2169332023-11-13T21:21:44Z2023-11-13T21:21:44ZQuébec’s summer 2023 wildfires were the most devastating in 50 years. Is the worst yet to come?<figure><img src="https://images.theconversation.com/files/557286/original/file-20231027-23-ya6je6.jpg?ixlib=rb-1.1.0&rect=6%2C6%2C2032%2C1066&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Forest fires were mostly started by lightning. Their spread was then exacerbated by a lack of precipitation and abnormally high temperatures.</span> <span class="attribution"><span class="source">(Victor Danneyrolles)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>After a summer of exceptional wildfires, the return of cooler temperatures and snowy conditions will provide Québec’s forests a brief respite. </p>
<p>But how long will it last? Are events like these <a href="https://www.cbc.ca/news/climate/quebec-climate-change-wildfires-research-1.6943502">destined to become more frequent?</a></p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong>This article is part of <em>La Conversation Canada’s</em> series <a href="https://theconversation.com/ca-fr/topics/foret-boreale-138017">The boreal forest: A thousand secrets, a thousand dangers</a></strong></p>
<p><br><em>La Conversation Canada invites you to take a virtual walk in the heart of the boreal forest. In this series, our experts focus on management and sustainable development issues, natural disturbances, the ecology of terrestrial wildlife and aquatic ecosystems, northern agriculture and the cultural and economic importance of the boreal forest for Indigenous peoples. We hope you have a pleasant — and informative — walk through the forest!</em></p>
<hr>
<p>As experts in disturbance dynamics occurring in the boreal environment, we are assessing the fires that occurred in Québec in 2023 to provide insights into their causes and consequences.</p>
<h2>Millions of hectares affected</h2>
<p>According to Québec’s <a href="https://sopfeu.qc.ca/en/">Société de protection des forêts contre le feu</a> (Society for the protection of forests against fire, SOPFEU), nearly 700 fires have burned approximately 5.1 million hectares (equivalent to the territory size of Costa Rica), both north and south of the northern forest limit designated by the province — or the boundary that separates northern Québec forests from the southern forests, where logging is conducted.</p>
<p>At the beginning of October, fifteen of the fires that had started in the summer were still active in western Québec. Three of them, although contained, had burned a total of almost 700,000 hectares within the <a href="https://www.pbs.org/newshour/world/canadian-province-of-quebec-looks-for-international-support-to-fight-over-160-wildfires">intensive protection zone</a>, where the SOPFEU systematically fights all fires. </p>
<p>In the <a href="https://sopfeu.qc.ca/lintervention-de-la-sopfeu-dans-les-differentes-zones-de-protection/">northern zone</a>, twelve fires were still under surveillance, some not exceeding 20 hectares, others covering more than a million hectares. Out of the total area burned in 2023 in Québec, three-quarters (3.8 million hectares) were in the northern zone. South of the 50th parallel, within the intensive protection zone, approximately 1.4 million hectares burned, which is more than 80 times the annual average of the past ten years.</p>
<p>When we compare the 2023 fire season to <a href="https://www.donneesquebec.ca/recherche/dataset/feux-de-foret">datasets available since the 1970s</a>, it becomes quite clear that this year was unusual compared to recent decades. Yet, although these fires are impressive and difficult to contain, they are still within the range of “natural variability” observed in previous centuries.</p>
<p>Several <a href="https://doi.org/10.1071/WF22090">studies</a> have shown that particularly intense fire cycles were common in Québec during the period from 1910-1920. These were even more common in the 18th and 19th centuries when warm and dry climatic conditions were particularly conducive to forest fires.</p>
<h2>Exceptional weather conditions</h2>
<p>Like historic forest fires, fire outbreaks in Québec in 2023 were fuelled by <a href="https://www.worldweatherattribution.org/climate-change-more-than-doubled-the-likelihood-of-extreme-fire-weather-conditions-in-eastern-canada/">intense weather conditions</a>. Starting in June, after an already dry month of May, a significant increase in fires was observed in the intensive protection zone. The northern zone was affected throughout the three summer months.</p>
<p>These fires were mainly started by lightning. Their spread was then exacerbated by low precipitation and abnormally high temperatures. <a href="https://www.environnement.gouv.qc.ca/climat/faits-saillants/2023/juin.htm">Temperatures exceeded the 1981-2010 average for the month of June by 2.3°C</a>, setting a record for the warmest June recorded in Québec in at least a hundred years.</p>
<p>These exceptional weather conditions were partly influenced by the El Niño phenomenon, a cyclical warming of the Pacific Ocean known for its impact on terrestrial weather conditions. The trend continued into July, which witnessed exceptionally high average temperatures, well above normal (+2.7°C).</p>
<h2>Multiple consequences</h2>
<p>The simultaneous outbreak of numerous fires and their rapid spread have had multiple effects on wildlife, forests, the climate, and human populations.</p>
<p>The fires have altered the structure and composition of vegetation, causing disruption to wildlife habitats as well as <a href="https://www.cbc.ca/news/canada/montreal/quebec-wildfires-destabilize-quebec-wildlife-1.6867744">displacement and mortality among animals</a>. As a result, the hunting, fishing and harvesting territories of Indigenous communities have been affected.</p>
<p>In addition to representing a direct threat to public safety, the smoke from the fires caused respiratory problems, leading to <a href="https://globalnews.ca/news/9791853/quebec-wildfires-more-evacuations-ordered/">the evacuation of thousands of people in several regions of Québec</a>. The deterioration in air quality was felt not only across Canada and the <a href="https://www.bbc.com/news/world-us-canada-65828469">United States</a>, but also as far as <a href="https://www.cbc.ca/news/canada/montreal/nasa-quebec-fire-smoke-europe-1.6890108">Europe</a>. Fortunately, evacuations were carried out in time, and casualties were avoided. However, there was some material damage.</p>
<p>In terms of their impact on the climate, large fires released several megatons of carbon dioxide stored in trees and soils, <a href="https://cdnsciencepub.com/doi/10.1139/er-2013-0062">contributing to an increase in atmospheric concentrations of greenhouse gases</a> (CO<sub>2</sub>, CH<sub>4</sub>).</p>
<p>While the fires have had significant consequences, <a href="https://theconversation.com/forest-fires-north-americas-boreal-forests-are-burning-a-lot-but-less-than-150-years-ago-201365">they can sometimes be beneficial for certain organisms</a>. We can consider tree species like jack pine, which depend on fires for regeneration, and numerous animal species that thrive in burned forests.</p>
<h2>What can we expect in the future?</h2>
<p>Québec’s forests have been burning and regenerating cyclically for millennia. However, it is imperative to recognize that these cycles can evolve over time.</p>
<p>The 2023 fire season highlights the urgency of preparing for significant changes in disturbance dynamics, including the possibility of such events recurring more frequently.</p>
<p>As climate change progresses, periods of drought could become more frequent if precipitation fails to compensate for rising temperatures, as observed in the 20th century.</p>
<p>This combination of factors increases the likelihood of an increase in the number, size, and intensity of wildfires.</p>
<p>Such changes threaten the natural regeneration of forests and could lead to the formation of treeless areas, victims of too frequent fires <a href="https://www.pnas.org/doi/full/10.1073/pnas.2024872118">for vegetation to have time to regenerate</a>.</p>
<p>These conditions could also be exacerbated by the continued expansion of logging. <a href="https://www.theglobeandmail.com/canada/article-as-canadas-boreal-forests-burn-again-and-again-they-wont-grow-back-the/">Preliminary analyses</a> have shown that more than 300,000 hectares of forests burned in 2023 may not regenerate, mainly due to the effects of logging in recent decades.</p>
<p>The consequences of major forest fires highlight the climate challenges we face. They demonstrate the need to develop mitigation and adaptation measures aimed at protecting vulnerable forest ecosystems and their inhabitants.</p>
<p>It is therefore imperative to learn lessons from the 2023 fire season to strengthen the resilience of forests and communities to climate change and limit damages caused by fires. This involves reducing risk, protecting the most vulnerable areas, and raising awareness among local populations.</p><img src="https://counter.theconversation.com/content/216933/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yves Bergeron received funding from FRQNT, NSERC and MNRF.</span></em></p><p class="fine-print"><em><span>Dorian M. Gaboriau, Jonathan Lesven et Victor Danneyrolles ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur poste universitaire.</span></em></p>The forest fires of the summer of 2023 in Québec were devastating. It was the worst year in 50 years. But with climate change, the worst may be yet to come.Dorian M. Gaboriau, Postdoctorant en paléoécologie, Université du Québec en Abitibi-Témiscamingue (UQAT)Jonathan Lesven, Doctorant en paléoécologie, Université du Québec en Abitibi-Témiscamingue (UQAT)Victor Danneyrolles, Professeur-chercheur en écologie forestière, Université du Québec à Chicoutimi (UQAC)Yves Bergeron, Professeur écologie et aménagement forestier, Université du Québec en Abitibi-Témiscamingue (UQAT)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2140652023-10-26T01:12:15Z2023-10-26T01:12:15Z3 ways to prepare for bushfire season if you have asthma or another lung condition<figure><img src="https://images.theconversation.com/files/555707/original/file-20231025-25-7t7ylm.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C994%2C666&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sunlight-shining-through-smoke-haze-coloring-1605818323">Shutterstock</a></span></figcaption></figure><p>Australia’s bushfire season is officially <a href="https://www.nsw.gov.au/media-releases/fire-season-commences">under way</a> during an <a href="https://www.climatecouncil.org.au/resources/what-the-return-of-el-nino-means/">El Niño</a>. And after three wet years, and the <a href="https://www.afac.com.au/auxiliary/publications/newsletter/article/seasonal-bushfire-outlook-spring-2023#:%7E:text=For%20spring%202023%2C%20increased%20risk,bushfire%20this%20season%20are%20widespread">plant growth</a> that comes with it, there’s fuel to burn.</p>
<p>With the prospect of <a href="https://theconversation.com/its-official-australia-is-set-for-a-hot-dry-el-nino-heres-what-that-means-for-our-flammable-continent-209126">catastrophic bushfire</a> comes smoke. This not only affects people in bushfire regions, but those <a href="https://theconversation.com/bushfire-smoke-is-everywhere-in-our-cities-heres-exactly-what-you-are-inhaling-129772">in cities and towns</a> far away, as smoke travels. </p>
<p>People with a <a href="https://www.atsjournals.org/doi/10.1164/rccm.202012-4471LE">lung condition</a> are among those especially affected.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/our-mood-usually-lifts-in-spring-but-after-early-heatwaves-and-bushfires-this-year-may-be-different-213643">Our mood usually lifts in spring. But after early heatwaves and bushfires, this year may be different</a>
</strong>
</em>
</p>
<hr>
<h2>What’s so dangerous about bushfire smoke?</h2>
<p>Bushfire smoke <a href="https://www.health.nsw.gov.au/environment/air/Pages/common-air-pollutants.aspx">pollutes the air</a> we breathe by increasing the concentration of particulate matter (or PM).</p>
<p>Once inhaled, <a href="https://www.health.nsw.gov.au/environment/air/Pages/particulate-matter.aspx">small particles</a> (especially with a diameter of 2.5 micrometres or less, known as PM2.5) can get deep into the lungs and into the bloodstream. </p>
<p>Concentration of gases in the air – such as <a href="https://www.health.nsw.gov.au/environment/air/Pages/ozone.aspx">ozone</a>, <a href="https://www.health.nsw.gov.au/environment/air/Pages/nitrogen-dioxide.aspx">nitrogen dioxide</a> and <a href="https://www.health.nsw.gov.au/environment/air/Pages/sulphur-dioxide.aspx">sulfur dioxide</a> – also increase, to pollute the air.</p>
<p>All these cause the airway to <a href="https://www.alfredhealth.org.au/news/the-effects-of-bushfire-smoke-explained/">narrow and spasm</a>, making it hard to breathe. </p>
<p>This can be even worse for people with existing asthma or other respiratory conditions whose airways are already inflamed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bushfire-smoke-is-everywhere-in-our-cities-heres-exactly-what-you-are-inhaling-129772">Bushfire smoke is everywhere in our cities. Here's exactly what you are inhaling</a>
</strong>
</em>
</p>
<hr>
<p>Emergency department visits and hospital admissions for asthma-related symptoms <a href="https://www.sciencedirect.com/science/article/pii/S0013935119305742?dgcid=author">rise</a> <a href="https://pubmed.ncbi.nlm.nih.gov/33601224/">after exposure</a> to bushfire smoke.</p>
<p>Smoke from the bushfires in summer 2019/20 <a href="https://www.mja.com.au/system/files/issues/213_06/mja250545.pdf">resulted in</a> an estimated 400 deaths or more from any cause, more than 1,300 emergency department visits for asthma symptoms, and more than 2,000 hospital admissions for respiratory issues.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1265122247628386305"}"></div></p>
<p>Even if symptoms are not serious enough to warrant emergency medical attention, exposure to bushfire smoke <a href="https://www.qld.gov.au/health/staying-healthy/environmental/after-a-disaster/bushfires/bushfire-smoke-and-your-health#:%7E:text=Signs%20of%20smoke%20irritation%20include,throat%2C%20runny%20nose%20and%20coughing">can lead to</a> cough, nasal congestion, wheezing and asthma flares.</p>
<p>If you have <a href="https://theconversation.com/what-causes-asthma-what-we-know-dont-know-and-suspect-96409">asthma</a>, <a href="https://theconversation.com/explainer-what-is-chronic-obstructive-pulmonary-disease-25539">chronic obstructive pulmonary disease</a>, <a href="https://www.nhlbi.nih.gov/health/bronchiectasis#:%7E:text=Bronchiectasis%20is%20a%20condition%20that,These%20tubes%20are%20called%20airways.">bronchiectasis</a> or another lung condition, or you care for someone who has, here’s what you can do to prepare for the season ahead.</p>
<h2>1. Avoid smoke</h2>
<p>Monitor your local air quality by downloading one or both of these apps:</p>
<ul>
<li><p><a href="https://asthma.org.au/what-we-do/current-projects/airsmart/">AirSmart</a> from Asthma Australia has live air-quality information to help you plan and act</p></li>
<li><p><a href="https://airrater.org/">AirRater</a>, developed by Australian scientists, can be another useful app to monitor your environment, track your symptoms and help manage your health. </p></li>
</ul>
<p>During times of poor air quality and smoke stay indoors and avoid smoke exposure. Close windows and doors, and if you have one, use an air conditioner to recirculate the air. </p>
<p>Avoid unnecessary <a href="https://28bysamwood.com/blog/fitness/should-you-exercise-if-its-smoky-outside/">physical activity</a> which makes us breathe more to deliver more oxygen to the body, but also means we inhale more polluted air. Consider temporarily moving to a safer residence. </p>
<p>Well-fitting N95/P2 masks can reduce your exposure to fine smoke particles if you must travel. However they can make it more difficult to breathe if you are unwell. In that case, you may find a mask with a valve <a href="https://theconversation.com/how-to-protect-yourself-against-bushfire-smoke-this-summer-154720">more comfortable</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person holding a N95/P2 respirator" src="https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555709/original/file-20231025-17-n7pp9e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Well-fitting N95/P2 masks can help.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sydney-australia-20200105-trojan-p2-disposable-1608222889">Daria Nipot/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-protect-yourself-against-bushfire-smoke-this-summer-154720">How to protect yourself against bushfire smoke this summer</a>
</strong>
</em>
</p>
<hr>
<h2>2. Have an action plan</h2>
<p>Taking your regular preventer medication ensures your lung health is optimised before the danger period. </p>
<p>Ensure you have a <a href="https://www.nationalasthma.org.au/health-professionals/asthma-action-plans">written action plan</a>. This provides you with clear instructions on how to take early actions to prevent symptoms deteriorating or to reduce the severity of flare-ups. Review this plan with your GP, share it with a family member, pin it to the fridge.</p>
<p>Make sure you have emergency medication available, know when to call for help, and what medication to take while you wait. You may consider storing an emergency “reliever puffer” in your home or with a neighbour.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-manage-your-essential-medicines-in-a-bushfire-or-other-emergency-127516">How to manage your essential medicines in a bushfire or other emergency</a>
</strong>
</em>
</p>
<hr>
<h2>3. Have the right equipment</h2>
<p>High-efficiency particulate air (HEPA) filters <a href="https://www.phrp.com.au/issues/online-early/residential-indoor-air-quality-and-hepa-cleaner-use/">can reduce</a> smoke exposure inside the home during a fire event by 30-74%. These filters remove particulate matter from the air. </p>
<p>A spacer, which is a small chamber to contain inhaled medication, can help you take emergency medication if you are breathing quickly. You may want to have one to hand.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-face-masks-to-air-purifiers-what-actually-works-to-protect-us-from-bushfire-smoke-128633">From face masks to air purifiers: what actually works to protect us from bushfire smoke?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214065/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>People with a lung condition are among those particularly vulnerable to bushfire smoke. But you can prepare for the season ahead.Kazi Mizanur Rahman, Associate Professor of Healthcare Innovations, Faculty of Health Sciences and Medicine, Bond UniversityJoe Duncan, Clinical Associate Lecturer, Northern Clinical School and Lecturer, Internal Medicine. Rural Clinical School (Northern Rivers), University of SydneyJo Longman, Senior Research Fellow, The University Centre for Rural Health, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2140602023-10-13T18:01:21Z2023-10-13T18:01:21ZWildfire smoke leaves harmful gases in floors and walls − air purifiers aren’t enough, new study shows, but you can clean it up<p>When wildfire smoke turns the air brown and hazy, you might think about heading indoors with the windows closed, running an air purifier or even wearing a mask. These are all good strategies to reduce exposure to the particles in wildfire smoke, but smoky air is also filled with potentially harmful gases. Those gases can get into buildings and remain in the walls and floors for weeks.</p>
<p>Getting rid of these gases isn’t as simple as turning on an air purifier or opening a window on a clear day.</p>
<p>In a new study published in the journal Science Advances, colleagues and I tracked <a href="https://www.science.org/doi/10.1126/sciadv.adh8263">the life of these gases</a> in a home exposed to wildfire smoke. We also found that the best way to get rid of the risk is among the simplest: start cleaning.</p>
<h2>The challenge of smoke particles and gases</h2>
<p>In December 2021, several of my friends and colleagues were affected by the <a href="https://theconversation.com/homes-that-survived-the-marshall-fire-1-year-ago-harbored-another-disaster-inside-heres-what-weve-learned-about-this-insidious-urban-wildfire-risk-196926">Marshall Fire</a> that burned about 1,000 homes in Boulder County, Colorado. The “lucky” ones, whose homes were still standing, asked me what they should do to clean their houses. I am <a href="https://scholar.google.com/citations?user=XpzGDEUAAAAJ&hl=en">an atmospheric and indoor chemist</a>, so I started looking into the published research, but I found very few studies on what happens after a building is exposed to smoke.</p>
<p>What scientists did know was that <a href="https://doi.org/10.1039/D1EM00087J">smoke particles end up on indoor surfaces</a> – floors, walls, ceilings. We knew that air <a href="https://doi.org/10.1080/02786826.2022.2054674">filters</a> could remove particles from the air. And colleagues and I were just beginning to understand that volatile organic compounds, which are traditionally thought to stay in the air, could actually <a href="https://doi.org/10.1126/sciadv.aay8973">stick to surfaces inside a home and build up reservoirs</a> – invisible pools of organic molecules that can contribute to the air chemistry inside the house.</p>
<p>Volatile organic compounds, or VOCs, are compounds that easily become gases at room temperature. They include everything from limonene in lemons to benzene in gasoline. VOCs aren’t always hazardous to human health, but <a href="https://doi.org/10.1021/acs.est.0c04497">many VOCs in smoke are</a>. I started to wonder whether the VOCs in wildfire smoke could also stick to the surfaces of a house.</p>
<h2>Tracking lingering risks in a test house</h2>
<p>I worked with researchers from across the U.S. and Canada to explore this problem during the <a href="https://indoorchem.org/projects/casa/">Chemical Assessment of Surfaces and Air</a>, or CASA, study in 2022. We built on <a href="https://doi.org/10.1039/C9EM00228F">HOMEChem</a>, a previous study in which we looked at how cooking, cleaning and occupancy could change indoor air.</p>
<p>In CASA, we studied what happens when pollutants and chemicals get inside our homes – pesticides, smog and even wood smoke.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VptLTyx0ptk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Tracking VOCs from smoke and other sources.</span></figcaption>
</figure>
<p>Using a cocktail smoker and wood chips, we created a surprisingly chemically accurate proxy for wildfire smoke and released small doses into a <a href="https://www.nist.gov/el/net-zero-energy-residential-test-facility">test house</a> built by the National Institute of Standards and Technology. NIST’s house allowed us to conduct controlled chemistry experiments in a real-world setting.</p>
<p>We even aged the smoke in a large bag with ozone to simulate what happens when smoke travels long distances, like the smoke from Canadian wildfires that <a href="https://theconversation.com/wildfire-smoke-and-dirty-air-are-also-climate-change-problems-solutions-for-a-world-on-fire-207676">moved into the U.S.</a> in the summer of 2023. Smoke chemistry changes as it travels: <a href="https://doi.org/10.1021/acsearthspacechem.9b00125">Particles become more oxidized</a> and <a href="https://doi.org/10.1073/pnas.2012218117">brown</a>, while VOCs <a href="https://doi.org/10.1021/acs.est.1c05684">break down</a> and the smoke loses its distinctive smell.</p>
<h2>How VOCs behave in your home</h2>
<p>What we found in CASA was intriguing. While smoke particles quickly settled on indoor surfaces, <a href="https://www.science.org/doi/10.1126/sciadv.adh8263">VOCs were more insidious</a>.</p>
<p>At first, the house took up these smoke VOCs – on floors, walls and building surfaces. But once the initial smoke cleared, the house would slowly release those VOCs back out over the next hours, days or even months, depending on the type of VOC.</p>
<p>This release is what we call a partitioning process: During the smoke event, individual VOC molecules in the air attach to indoor surfaces with weak chemical bonds. The <a href="https://www.int-ads-soc.org/what-is-adsorption/">process is called adsorption</a>. As smoke clears and the air cleans out, the bonds can break, and molecules “desorb” back out into the air.</p>
<p><iframe id="v93H7" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/v93H7/10/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>We could watch this partitioning happen in the air by measuring smoke VOC concentrations. On surfaces, we could measure the weight of smoke VOCs that deposited on very sensitive balances and then were slowly released.</p>
<p>Overall, we concluded that this surface reservoir <a href="https://www.science.org/doi/10.1126/sciadv.adh8263">allows smoke VOCs to linger indoors</a>, meaning that people are exposed to them not just during the major smoke event but also long after.</p>
<h2>Why worry about VOCs?</h2>
<p>Smoke VOCs include well-known <a href="https://doi.org/10.1029/2021GH000546">carcinogens</a>, and high levels of exposure can induce <a href="https://theconversation.com/wildfire-smoke-can-harm-human-health-even-when-the-fire-is-burning-hundreds-of-miles-away-a-toxicologist-explains-why-206057">respiratory and health problems</a>.</p>
<p>While smoke VOC concentrations in our test house decreased with time, they remained persistently elevated above normal levels.</p>
<p>Given that <a href="https://doi.org/10.1021/acs.est.2c01381">VOC concentrations from other sources</a>, such as cooking and cleaning, can already be high enough in homes to harm health, this additional long-term exposure source from smoke could be important. Further toxicology studies will be needed to determine the significance of its health effects.</p>
<h2>How to clean up when smoke gets in</h2>
<p>So, what can you do to remove these lingering smoke gases?</p>
<p>We found that air purifiers can remove only some of the VOCs that are in the air – they can’t clean the VOCs on your floors or in your walls. They also work only when they’re running, and even then, air purifiers don’t work particularly well to reduce VOCs.</p>
<p>Opening windows to ventilate will clean the air, if it isn’t smoggy or smoky outside. But as soon as we closed windows and doors, smoke VOCs started to bleed off the surface reservoirs and into the air again, resulting in an elevated, near-constant concentration.</p>
<p>We realized that to permanently remove those smoke VOCs, we had to physically remove them from surfaces.</p>
<figure class="align-center ">
<img alt="A young scientist, wearing a face mask, and a large air purifier." src="https://images.theconversation.com/files/550124/original/file-20230925-19-s23qd0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550124/original/file-20230925-19-s23qd0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550124/original/file-20230925-19-s23qd0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550124/original/file-20230925-19-s23qd0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550124/original/file-20230925-19-s23qd0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550124/original/file-20230925-19-s23qd0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550124/original/file-20230925-19-s23qd0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A scientist takes samples while running an air purifier in the test house. The results show the air purifier helps while it’s running, but only for gases in the air.</span>
<span class="attribution"><span class="source">John Eisele/Colorado State University</span></span>
</figcaption>
</figure>
<p>The good news is that cleaning surfaces by vacuuming, dusting and mopping with a commercial, nonbleach solution did the trick. While some remediation companies may do this surface cleaning for you after extreme exposures, surface cleaning after any smoke event – like <a href="https://theconversation.com/north-americas-summer-of-wildfire-smoke-2023-was-only-the-beginning-210246">Canadian wildfire smoke</a> drifting into homes in 2023 – should effectively and permanently reduced smoke VOC levels indoors.</p>
<p>Of course, we could reach only a certain number of surfaces – it’s hard to vacuum the ceiling! That meant that surface cleaning improved but didn’t eliminate smoke VOC levels in the house. But our study at least provides a path forward for cleaning indoor spaces affected by air pollutants, whether from wildfires, chemical spills or other events. </p>
<p>With wildfires <a href="https://www.unep.org/news-and-stories/story/air-pollution-wildfires-expected-surge-world-warms">becoming more frequent</a>, surface cleaning can be an easy, cheap and effective way to improve indoor air quality.</p><img src="https://counter.theconversation.com/content/214060/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Delphine Farmer receives funding from the Alfred P. Sloan Foundation, W.M. Keck Foundation, National Science Foundation, Department of Energy, and the National Oceanic and Atmospheric Administration.</span></em></p>Wildfire smoke, even from fires far away, carries potentially harmful gases that, once inside, tend to stick around. An air quality specialist offers an easy, cheap, effective way to deal with it.Delphine Farmer, Professor of Chemistry, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2117472023-09-28T19:58:50Z2023-09-28T19:58:50Z‘You’re constantly worrying’: pregnant women, bushfire smoke and the impossibility of safety<p>Smoke covered large swathes of Australia during the catastrophic summer fires of 2019-2020. You could see the plumes from space. Over 20% of Australia’s forests <a href="https://www.theguardian.com/australia-news/2020/feb/25/unprecedented-globally-more-than-20-of-australias-forests-burnt-in-bushfires">went up</a> in smoke and flame. </p>
<p>As the fires spread, smoke covered towns and cities. Millions of people were suddenly confronted with bad air. Many had children. Many were pregnant. All worried about what the smoke might mean for their child. </p>
<p>Our <a href="https://bristoluniversitypress.co.uk/reproduction-kin-and-climate-crisis">new book</a> explores the worries and desperation of people who were pregnant or parenting during the unprecedented fires over the 2019–2020 summer. We drew on in-depth stories from 25 mothers (and sometimes their partners). </p>
<p>The smoke was something they had no control over. But public health advice told them they had the responsibility to keep their child safe. Mothers and their partners worried endlessly about what damage the pollutants in the air were doing. This, we argue, speaks to how those who have done little to fuel the climate crisis can be particularly at risk. </p>
<h2>What did we find?</h2>
<p>One woman, Renee, told us about the anxiety of being pregnant and with two small children in the smoke: </p>
<blockquote>
<p>I was really worried about lung damage for my kids upstairs, but I was also worried, [for] like, brain development at that point, as you get into the end of the pregnancy […] I kept having conversations with myself going, ‘I’m not in my first 12 weeks, surely that’s riskier. I’m in this safer zone’.</p>
</blockquote>
<p>Renee’s story speaks to how our interviewees tried to take responsibility for themselves and their foetuses. </p>
<p>It was a common thread. The 25 mothers and partners we interviewed were living in Canberra or on the south coast of New South Wales. These areas were among the worst affected by smoke. </p>
<p>Renee’s feelings of risk and responsibility are amplified in an era that historian of fire Stephen Pyne has <a href="https://theconversation.com/california-wildfires-signal-the-arrival-of-a-planetary-fire-age-125972">named the “Pyrocene</a>”, a time when bushfires and the burning of fossil fuels are careering out of control. </p>
<p>Our research shows pregnant people were framed as “doubly vulnerable” to smoke, due to their own exposure and that of their foetus. Health advice from organisations such as the <a href="https://www.thewomens.org.au/news/advice-for-pregnant-women-around-smoke-haze">Royal Women’s Hospital</a> urged them to stay indoors, use air-conditioning and to spend time at libraries and shopping centres to avoid exposure.</p>
<h2>Who is responsible?</h2>
<p>Given health warnings about smoke exposure, it’s not surprising our interviewees expressed considerable concern for their unborn babies. </p>
<p>Alice, pregnant during the fires: </p>
<blockquote>
<p>It was really constantly on my mind, and I tried to kind of not get too anxious about it, but it was really difficult because […] I mean, you just think about it all the time. You’re just constantly worrying when you’re pregnant what’s going to affect the baby. Like everything you do.</p>
</blockquote>
<p>Gina, pregnant during the fires: </p>
<blockquote>
<p>It was just always kind of lingering, like we were just unsure about what kind of effects it would have on the development of his organs and whatever else. I was obviously more stressed than my husband, just because, you know, the mother is carrying the baby and there’s more stress just naturally on the mum</p>
</blockquote>
<p>Even while worrying about the health of their babies, women also felt the responsibility for keeping them “safe” from smoke exposure fell primarily to them. </p>
<p>What we ask is – is this fair? As recent research <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(23)00134-1/fulltext">makes clear</a>, pollutants such as bushfire smoke are uncontrollable. </p>
<p>Feminist scholars <a href="https://press.uchicago.edu/ucp/books/book/chicago/M/bo117202096.html">note that</a> public health advice and scientific research tends to emphasise how vulnerable the foetus is and, by extension, place responsibility on the mother – even while acknowledging how little control they have over the situation. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-hits-low-income-earners-harder-and-poor-housing-in-hotter-cities-is-a-disastrous-combination-180960">Climate change hits low-income earners harder – and poor housing in hotter cities is a disastrous combination</a>
</strong>
</em>
</p>
<hr>
<h2>When responsibility meets uncertainty</h2>
<p>Australia has long been affected by bushfires. But they’re <a href="https://theconversation.com/yes-climate-change-is-bringing-bushfires-more-often-but-some-ecosystems-in-australia-are-suffering-the-most-211683">getting worse</a> as the world heats up. </p>
<p>There’s no roadmap for how to live with sudden crises such as fires or the long, slow burn of incremental change. We’re all experimenting at individual, household and community levels as well as nationally and regionally. </p>
<p>Many of us are <a href="https://theconversation.com/climate-change-hits-low-income-earners-harder-and-poor-housing-in-hotter-cities-is-a-disastrous-combination-180960">having to tinker</a> with our machines and our homes to take care of others and to survive the new extremes. </p>
<p>Climate change is happening to the globe. But the devastation wreaked by extreme weather, disruption to farming or intensified fires is not evenly distributed, either by who did the most to cause it or by who is most hard hit. </p>
<p>Wealth magnifies unfairness. Those who have done the most to create and benefit from carbon-intensive capitalism are more likely to be able to shield themselves from <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)00919-4/fulltext">its effects</a>, while people who are <a href="https://doi.org/10.1016/j.envres.2019.04.012">pregnant and parenting</a>, and <a href="https://caepr.cass.anu.edu.au/research/publications/aboriginal-peoples-and-response-2019-2020-bushfires">First Nations people</a> – especially children aged five and under – are more vulnerable. </p>
<p>What we point to is a question. How can we find ways to take care of foetuses and young children without forcing parents (and mothers, in particular) to shoulder the impossible responsibility of safety? </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-black-summer-bushfires-put-an-enormous-strain-on-families-with-young-children-we-cant-make-the-same-mistakes-again-205026">The Black Summer bushfires put an enormous strain on families with young children. We can't make the same mistakes again</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/211747/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If you were pregnant or parenting during Australia’s 2019–20 summer of smoke and fire, chances are you felt acutely anxious – and grappling with impossible responsibility.Mary Lou Rasmussen, Professor, School of Sociology, Australian National UniversityCelia Roberts, Professor of sociology, Australian National UniversityLouisa Allen, Professor, Faculty of Education and Social Work, University of Auckland, Waipapa Taumata RauRebecca Williamson, Research Officer, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2102462023-09-01T12:43:36Z2023-09-01T12:43:36ZNorth America’s summer of wildfire smoke: 2023 was only the beginning<p>Canada’s <a href="https://theconversation.com/yellowknife-and-kelowna-wildfires-burn-in-what-is-already-canadas-worst-season-on-record-211817">seemingly endless wildfires</a> in 2023 introduced millions of people across North America to the health hazards of wildfire smoke. While Western states have contended with smoky fire seasons for years, the air quality alerts across the U.S. Midwest and Northeast this summer reached <a href="https://www.epa.gov/outdoor-air-quality-data/air-data-daily-air-quality-tracker">levels never seen there before</a>.</p>
<p>The smoke left the air so unhealthy in Philadelphia on June 7, 2023, that the Phillies-Detroit Tigers Major League Baseball <a href="https://www.reuters.com/sports/mlb-wnba-nwsl-games-postponed-due-poor-air-quality-us-2023-06-07/">game was postponed</a>. That same week, New York City residents hunkered down indoors for several days as a smoky haze hung over the city, turning the skies orange and exposing millions of people to the worst air quality in the world.</p>
<p>Smoke also drifted into the Midwest, triggering the highest air quality index levels in the Chicago area in at least 24 years, forcing the cancellation of numerous summer activities and leaving residents with raspy voices. In several states, people woke up to smoky skies day after day.</p>
<figure class="align-center ">
<img alt="A young man rides a rental bike along Chicago's Lake Michigan shore with smoke obscuring the view of the city skyline in the background." src="https://images.theconversation.com/files/545610/original/file-20230830-29-xqvrh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545610/original/file-20230830-29-xqvrh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545610/original/file-20230830-29-xqvrh9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545610/original/file-20230830-29-xqvrh9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545610/original/file-20230830-29-xqvrh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545610/original/file-20230830-29-xqvrh9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545610/original/file-20230830-29-xqvrh9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Chicago was under air quality alerts several times during the summer of 2023 as wildfire smoke blew in from Canada.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/wildfire-smoke-clouds-the-skyline-on-june-28-2023-in-news-photo/1503491525">Scott Olson/Getty Images</a></span>
</figcaption>
</figure>
<p>The pressing question on many people’s minds: “Is this the new normal?” From <a href="https://scholar.google.com/citations?user=CKRhPGIAAAAJ&hl=en">our perspective as</a> <a href="https://scholar.google.com/citations?user=MHbvpzAAAAAJ&hl=en">air quality</a> <a href="https://scholar.google.com/citations?user=QdkDnPgAAAAJ&hl=en">scientists</a>, we think the answer is likely “yes.”</p>
<h2>Global warming means more fires</h2>
<p>The wildfire smoke of 2023 highlights an emerging air quality trend. The U.S. had seen <a href="https://www.epa.gov/air-trends/particulate-matter-pm25-trends">decades of falling levels</a> of fine particulate matter pollution, PM2.5, thanks to environmental regulations and cleaner engines, factories and power plants. But wildfires’ contribution to air pollution is increasing again, resulting in flat or rising levels of air pollution in much of the country.</p>
<p>Climate models predicted this reality as global temperatures rise. Hotter, drier conditions, coupled with dry grasses and underbrush that accumulated over decades of fire suppression, have made large wildfires more common. Computer simulations of the <a href="https://doi.org/10.1073/pnas.1112839109">future in a warming climate</a> show more smoky days, higher smoke concentrations, larger burned areas and higher emissions – which further <a href="https://doi.org/10.1139/er-2013-0041">fuel climate change</a>.</p>
<p><iframe id="EtQZH" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/EtQZH/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>While prescribed fire and forest thinning can help reduce the number and intensity of fire outbreaks, <a href="https://doi.org/10.1016/j.scitotenv.2017.12.086">smoke exposure</a> is still likely to increase because of the increases in burned area anticipated as a result of large-scale shifts in temperature and moisture.</p>
<p>In short, people will need to learn to live with wildfire smoke. It won’t be every year, but we’re likely to see summers like 2023 more often.</p>
<p>Fortunately, there are several <a href="https://www.airnow.gov/wildfire-smoke-guide-publications/">tools and strategies for managing</a> a smokier future.</p>
<h2>Preparing for smoky days</h2>
<p>Managing the risk of wildfire smoke starts with making smart personal choices.</p>
<p>Think of smoke waves like heat waves: They’re easier to face if you’re prepared and know they’re coming. That means <a href="https://www.washingtonpost.com/technology/2023/06/07/best-air-quality-apps-wildfire-smoke/">paying attention to forecasts</a> and having face masks, air monitors and clean-air shelters available.</p>
<p><a href="https://theconversation.com/wildfire-smoke-can-harm-human-health-even-when-the-fire-is-burning-hundreds-of-miles-away-a-toxicologist-explains-why-206057">Inhaling PM2.5 and the chemicals</a> in wildfire smoke can exacerbate asthma, worsen existing respiratory and cardiac problems and leave people more susceptible to respiratory infection. People caring for individuals <a href="https://theconversation.com/extreme-heat-and-air-pollution-can-be-deadly-with-the-health-risk-together-worse-than-either-alone-187422">sensitive to smoke</a>, such as young children <a href="https://theconversation.com/extreme-heat-is-particularly-hard-on-older-adults-an-aging-population-and-climate-change-put-ever-more-people-at-risk-210049">and older adults</a>, will need to plan for their needs in particular.</p>
<figure class="align-center ">
<img alt="A baseball player standing beside the field adjusts a black mask over his face." src="https://images.theconversation.com/files/544875/original/file-20230826-29778-8y1qhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544875/original/file-20230826-29778-8y1qhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544875/original/file-20230826-29778-8y1qhv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544875/original/file-20230826-29778-8y1qhv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544875/original/file-20230826-29778-8y1qhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544875/original/file-20230826-29778-8y1qhv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544875/original/file-20230826-29778-8y1qhv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pittsburgh Pirates center fielder Andrew McCutchen wore a face mask to protect against smoke in the air during a Pirates-Padres game on June 29, 2023, in Pittsburgh.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/andrew-mccutchen-of-the-pittsburgh-pirates-puts-on-a-mask-news-photo/1508118494">Nick Cammett/Diamond Images via Getty Images</a></span>
</figcaption>
</figure>
<p>To prepare, read up on the risks and warning signs from public health professionals. Living with wildfire smoke may mean using air filtration devices, wearing N95 or KN95 masks on bad air days, modifying outdoor commuting patterns and activity schedules and changing household ventilation choices.</p>
<h2>What schools and communities can do</h2>
<p>Living with smoke will also require changes to how schools, businesses, apartment buildings and government buildings operate.</p>
<p>Schools can start with <a href="https://www.cde.ca.gov/ls/ep/documents/airqualityguidance.pdf">setting a threshold</a> for canceling outdoor activities and making sure staff are ready to meet the needs of kids with asthma.</p>
<p>Building managers may need to rethink air filtration and ventilation and deploy air quality sensors. Communities will also need contingency plans for festivals and recreation venues, as well as rules for business to protect outdoor workers.</p>
<figure class="align-center ">
<img alt="A school employee wearing a face mask and T-shirt with a big " src="https://images.theconversation.com/files/545608/original/file-20230830-15-p2h5n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545608/original/file-20230830-15-p2h5n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545608/original/file-20230830-15-p2h5n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545608/original/file-20230830-15-p2h5n9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545608/original/file-20230830-15-p2h5n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=487&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545608/original/file-20230830-15-p2h5n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=487&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545608/original/file-20230830-15-p2h5n9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=487&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Many schools installed better air filters and classroom air purifiers during spikes in the COVID-19 pandemic. Those measures may be necessary against smoky days in the future.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/eastern-h-s-custodian-raymond-woodfork-shows-tour-news-photo/1231802348">Michael S. Williamson/The Washington Post via Getty Images</a></span>
</figcaption>
</figure>
<p>Decisions on how to deal with smoke can be complicated. For example, selecting an air purifier <a href="https://doi.org/10.1111/ina.13163">can be a daunting task</a>, with over 900 products on the market. The effectiveness of different smoke management interventions are not well known and <a href="https://doi.org/10.1002/14651858.CD013441.pub2">can vary</a> depending on small implementation details, such as <a href="https://doi.org/10.1029/2021GH000482">how a mask fits</a> the wearer’s face, whether exterior doors and windows seal tightly and whether filters are installed properly and are replaced often enough.</p>
<h2>Improving smoke monitoring and forecasting</h2>
<p>The U.S. has an extensive air quality monitoring and forecasting system to help provide some early warning. It uses ground-based air quality monitors, satellite remote sensing systems to detect smoke and fires and <a href="https://fireaq.uiowa.edu">computer systems</a> that <a href="https://portal.airfire.org">tie observations together</a> with wind, <a href="https://fluid.nccs.nasa.gov/wxmaps/chem2d/?region=nam,">chemistry</a> and <a href="https://digital.mdl.nws.noaa.gov/airquality/?element=ozone01_bc&mapcenter=-96.00%2C40.00&mapzoom=5&subregion=CONUS&region=CONUS">weather</a>. These are supplemented by <a href="https://www.fs.usda.gov/research/news/highlights/continued-success-u.s.-interagency-wildland-fire-air-quality-response-program">expert guidance</a> from meteorologists.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of North America shows wildfire smoke from fires in Alberta and Ontario, Canada, detected strongly with poor air quality in the Great Lakes region, Northeast and Midwestern U.S." src="https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Smoke from wildfires in Canada was forecast across a large part of the U.S. on June 28, 2023. Dark purple dots indicate hazardous air quality; red is unhealthy; orange is unhealthy for sensitive groups; and yellow indicates moderate risk.</span>
<span class="attribution"><a class="source" href="https://fire.airnow.gov/">AirNow.gov</a></span>
</figcaption>
</figure>
<p>However, for average people trying to make decisions about the safety of outdoor activities, the current forecasting system is wanting. This is especially true when smoke blows in from fires far away, or when rapidly changing smoke emission rates and complex wind patterns lead to conflicting forecasts and advisories.</p>
<p>A few key improvements would go a long way for <a href="https://wpo.noaa.gov/improving-wildfire-prediction-with-convection-allowing-models/">practical decision making</a> around wildfire smoke, like whether to delay the start of soccer practice:</p>
<ul>
<li><p>Knowledge of how fires evolve hour by hour can improve the smoke estimates going into the <a href="https://doi.org/10.1071%2Fwf18204">forecast models</a>. </p></li>
<li><p>Providing smoke forecasts at neighborhood scale can better inform individuals and cities of pending risks. </p></li>
<li><p>More accurate 10-day forecasts would allow communities to plan. </p></li>
<li><p>Merging seasonal weather forecasts of precipitation, humidity and winds with satellite assessments of fuel conditions could enhance emergency planning for firefighters to help anticipate which regions and periods present the highest risks of fire and smoke.</p></li>
</ul>
<figure><img src="https://images.theconversation.com/files/544874/original/file-20230826-15-1jljmc.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1"><figcaption>Satellite data tracks black carbon from wildfire smoke moving into the U.S. Northeast, June 3-8, 2023. <a href="https://earthobservatory.nasa.gov/images/151442/hazardous-air-chokes-northeastern-states">NASA Earth Observatory video by Lauren Dauphin</a></figcaption></figure>
<p>Maintaining a strong air quality monitoring network is also important. State and local government agencies have reduced the <a href="https://www.gao.gov/assets/gao-21-38.pdf">number of ground monitors by about 10%</a> from its peak in 2001. Smoke estimates from satellites and low-cost portable sensors can help, but they work best when they can be cross-calibrated to a well-maintained network of high-accuracy monitors.</p>
<h2>We still have a lot to learn</h2>
<p>More effective adaptations to smoke will require more research to better understand the factors that make some people <a href="https://pubs.acs.org/doi/10.1021/acs.est.6b06200">more vulnerable to harm from smoke</a>, the effects of cumulative impacts of exposures to environmental stressors and smoke over the life span, and the efficacy and cost-effectiveness of adaptations. </p>
<p>For example, clean-air shelters – the equivalent to a cooling center during extreme heat – are gaining attention, but there is only limited guidance on what constitutes a clean-air shelter and where and when they would be used. A 2023 Government Accountability Office report <a href="https://www.gao.gov/products/gao-23-104723">called for better coordination</a> to help target resources where they can be most effective.</p>
<p>Living with smoke is emerging as a new reality. Next-generation tools need to be both clear and resilient to the compound hazards that develop when smoke <a href="https://theconversation.com/extreme-heat-and-air-pollution-can-be-deadly-with-the-health-risk-together-worse-than-either-alone-187422">hits simultaneously with other challenges</a>, such as extreme heat.</p><img src="https://counter.theconversation.com/content/210246/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charles O. Stanier receives funding from the National Science Foundation. </span></em></p><p class="fine-print"><em><span>Gregory Carmichael receives funding from the National Aeronautics and Space Administration.</span></em></p><p class="fine-print"><em><span>Peter S. Thorne receives funding from the U.S. National Institutes of Health and the Burroughs Wellcome Fund. </span></em></p>Thick smoke pouring in from Canada’s wildfires canceled baseball games and pushed air quality in major US cities to the worst in the world.Charles O. Stanier, Professor of Chemical and Biochemical Engineering, University of IowaGregory Carmichael, Professor of Chemical and Biochemical Engineering, University of IowaPeter S. Thorne, University of Iowa Distinguished Chair, Professor of Environmental Health, University of IowaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2114112023-08-27T13:32:37Z2023-08-27T13:32:37ZWildfire smoke is an increasing threat to Canadians’ health<iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/wildfire-smoke-is-an-increasing-threat-to-canadians-health" width="100%" height="400"></iframe>
<p><a href="https://www.canada.ca/en/environment-climate-change/services/environmental-indicators/air-pollutant-emissions.html">Air quality in Canada has improved</a> over the past several decades, and <a href="https://www.stateofglobalair.org/sites/default/files/documents/2022-09/soga-2020-report.pdf">Canada’s air is among the cleanest in the world</a>. But that progress is threatened by smoke from wildfires, which are becoming <a href="https://doi.org/10.4236/jep.2018.95028">more frequent and more intense with climate change</a>. </p>
<p>Canada’s 2023 wildfire season is <a href="https://ciffc.net/statistics">the worst on record</a>, with more than 5,800 reported fires and over 15 million hectares burned to date. </p>
<p>Globally, <a href="https://www.stateofglobalair.org/sites/default/files/documents/2022-09/soga-2020-report.pdf">air pollution is a leading cause of death and disease</a>. One of the best indicators of health risk from air pollution is the concentration of very small particles called PM2.5 (which stands for particulate matter smaller than 2.5 micrometres). </p>
<p>PM2.5 particles can deposit deep in the lungs and long-term exposure can <a href="https://www.stateofglobalair.org/sites/default/files/documents/2022-09/soga-2020-report.pdf">cause a wide range of health effects including respiratory and cardiovascular disease, diabetes, lung cancer and pregnancy complications</a>. <a href="https://doi.org/10.1126/sciadv.abo3381">Health effects can occur even at low concentrations</a>, including those below current <a href="https://ccme.ca/en/air-quality-report#slide-7">Canadian Ambient Air Quality Standards</a>.</p>
<p>Wildfires produce enormous quantities of PM2.5 and several other hazardous pollutants. Wildfire smoke can travel long distances, <a href="https://www.cnn.com/2023/06/06/us/new-york-air-pollution-canada-wildfires-climate/index.html">exposing large populations — both close to and far away from fires — to very high concentrations of pollution</a>. </p>
<h2>The health impact of wildfire smoke</h2>
<p>The pollution mixture and chemical composition of wildfire smoke is often different from the pollution emitted by other sources, and <a href="https://doi.org/10.1001/jamainternmed.2023.3300">these differences may influence toxicity</a>. The toxicity of wildfire smoke also <a href="https://doi.org/10.1289/EHP2200">depends on the type of vegetation and burning conditions</a> and <a href="https://doi.org/10.1007/s40726-023-00272-9">may change as the smoke “ages” in the atmosphere</a>. This underscores the need to distinguish the health impacts of wildfire smoke from the impacts of other pollution sources. </p>
<p>Evidence linking wildfire smoke with adverse health effects has been accumulating for years and the notion that wildfire smoke is “natural,” and therefore less harmful than other types of air pollution, is not supported by the evidence. </p>
<p>Most studies have evaluated the relationships between daily changes in smoke levels and indicators of health such as emergency department visits, hospital admissions or deaths. </p>
<p>There is strong evidence that these “acute” exposures to wildfire smoke <a href="https://doi.org/10.1289/ehp.1409277">increase the risk of respiratory illness and death</a>, and <a href="https://doi.org/10.1186/s12989-020-00394-8">evidence of effects on the cardiovascular system</a> is also growing. Older adults, people living in low-income areas, and those with asthma, chronic obstructive pulmonary disease (COPD), heart disease and other chronic conditions <a href="https://doi.org/10.1056/NEJMsr2028985">are most susceptible</a>. </p>
<p>The health effects of wildfire smoke likely extend beyond the lungs and heart. Recent studies indicate that exposure during pregnancy may increase the risks of <a href="https://doi.org/10.1016/j.envres.2021.111872">preterm birth</a> and <a href="https://doi.org/10.1038/s41370-020-00267-4">decreased birth weight</a>. Smoke may also <a href="https://doi.org/10.1289/EHP10498">reduce attention measured on cognitive tests</a> and <a href="https://doi.org/10.1001/jamainternmed.2023.3300">increase dementia risk</a>. </p>
<p>More studies are needed, but these effects could have important implications for health during vulnerable stages of life. </p>
<p><a href="https://doi.org/10.1016/j.envpol.2023.121041">Much less is known about the impacts of exposure to wildfire smoke over longer durations or from multiple episodes</a>. As more Canadians are exposed to smoke, and as the duration of the forest fire season increases, it will be critical to understand the long-term health impacts of repeated smoke exposure, especially among the most at-risk populations. </p>
<h2>Strategies to protect health</h2>
<p>Unlike <a href="https://doi.org/10.5772/9751">anthropogenic sources</a> of air pollution, emissions of wildfire smoke cannot be readily controlled at the source. But there are strategies that individuals and communities can use to reduce exposure and health risks. </p>
<p>Before fires begin, <a href="https://www.airnow.gov/publications/wildfire-smoke-guide/wildfire-smoke-a-guide-for-public-health-officials/">those with chronic conditions can discuss strategies for managing their health with their health-care providers, and ensure access to necessary medications</a>. During smoke events, <a href="https://doi.org/10.1289/ehp.1104447">staying indoors can be beneficial</a> because buildings reduce exposure to outdoor-generated pollution when windows and doors are closed. </p>
<p>Correctly sized portable HEPA filter air cleaners can <a href="https://doi.org/10.1016/j.atmosenv.2018.11.058">reduce indoor PM2.5 by as much as 80 per cent</a>. And well-fitting <a href="https://doi.org/10.1007/s40572-020-00296-z">N95 respirators (or comparable respirators designed and certified for occupational use) can reduce PM2.5 exposure</a> when outdoors or in transit. The <a href="https://weather.gc.ca/airquality/pages/index_e.html">Air Quality Health Index</a> and <a href="https://weather.gc.ca/firework/">smoke forecasts</a> can help Canadians decide when these strategies are needed.</p>
<p>These strategies also have limitations. For example, the recommendation to stay indoors assumes that individuals have stable and safe housing. It is also complicated by heat, <a href="https://doi.org/10.1097/ee9.0000000000000189">a major threat to health</a> that may <a href="https://doi.org/10.1164/rccm.202204-0657oc">amplify the effects of PM2.5</a>. </p>
<p>Portable air filters are prohibitively expensive for some families, they do not remove the gases found in wildfire smoke, and they will be less effective for those who spend time in other locations, such as outdoor workers. High quality respirators may be unavailable in some communities, may cause discomfort and <a href="https://doi.org/10.1007/s40572-020-00296-z">a good facial fit will be impossible for many children and some adults</a>. </p>
<p>Government and public health agencies can help to offset some of these limitations and ensure more equal protection from smoke by providing <a href="https://doi.org/10.3389/fpubh.2022.773428">accessible and clear messages to the public</a> and <a href="https://www.airnow.gov/publications/wildfire-smoke-guide/wildfire-smoke-a-guide-for-public-health-officials/">establishing clean air shelters in libraries, schools and other public buildings</a>. </p>
<p>Multiple overlapping strategies are needed to mitigate the health impacts of Canada’s worsening wildfires.</p><img src="https://counter.theconversation.com/content/211411/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Allen has used portable air cleaners purchased at a discounted rate from Woongjin-Coway in his research.</span></em></p><p class="fine-print"><em><span>Stephanie Cleland does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The notion that wildfire smoke is ‘natural,’ and therefore less harmful than other types of air pollution, is not supported by the evidence. Wildfire smoke has been linked to adverse health effects.Ryan W. Allen, Professor, Faculty of Health Sciences, Simon Fraser UniversityStephanie Cleland, Assistant Professor, Faculty of Health Sciences, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2104622023-08-10T20:00:53Z2023-08-10T20:00:53ZWhat’s in vapes? Toxins, heavy metals, maybe radioactive polonium<figure><img src="https://images.theconversation.com/files/541174/original/file-20230804-29-77kck2.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C997%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-girl-smokes-disposable-electronic-cigarette-1943062066">Shutterstock</a></span></figcaption></figure><p>If you asked me what’s in e-cigarettes, disposable vapes or e-liquids, my short answer would be “we don’t fully know”.</p>
<p>The huge and increasing range of products and flavours on the market, changes to ingredients when they are heated or interact with each other, and inadequate labelling make this a complicated question to answer.</p>
<p><a href="https://www.annualreviews.org/doi/pdf/10.1146/annurev-anchem-061318-115329">Analytical chemistry</a>, including <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">my own team’s research</a>, gives some answers. But understanding the health impacts adds another level of complexity. E-cigarettes’ risk to health varies depending on <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.1c00070">many factors</a> including which device or flavours are used, and how people use them.</p>
<p>So vapers just don’t know what they’re inhaling and cannot be certain of the health impacts.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-vapes-arent-95-less-harmful-than-cigarettes-heres-how-this-decade-old-myth-took-off-203039">No, vapes aren't 95% less harmful than cigarettes. Here's how this decade-old myth took off</a>
</strong>
</em>
</p>
<hr>
<h2>What do we know?</h2>
<p>Despite these complexities, there are some consistencies between what different laboratories find.</p>
<p>Ingredients include nicotine, flavouring chemicals, and the liquids that carry them – primarily propylene glycol and glycerine.</p>
<p><a href="https://www.industrialchemicals.gov.au/sites/default/files/2020-08/Non-nicotine%20liquids%20for%20e-cigarette%20devices%20in%20Australia%20chemistry%20and%20health%20concerns%20%5BPDF%201.21%20MB%5D.pdf">Concerningly</a>, we also find volatile organic compounds, particulate matter and carcinogens (agents that can cause cancer), many of which we know are harmful. </p>
<p>Our <a href="https://www.mja.com.au/journal/2019/210/3/nicotine-and-other-potentially-harmful-compounds-nicotine-free-e-cigarette">previous</a> <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">research</a> also found 2-chlorophenol in about half of e-liquids users buy to top-up re-fillable e-cigarettes. This is one example of a chemical with no valid reason to be there. Globally, it’s <a href="https://pubchem.ncbi.nlm.nih.gov/compound/2-Chlorophenol#section=Hazard-Classes-and-Categories">classified</a> as “harmful if inhaled”. Its presence is likely due to contamination during manufacturing.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/many-e-cigarette-vaping-liquids-contain-toxic-chemicals-new-australian-research-169615">Many e-cigarette vaping liquids contain toxic chemicals: new Australian research</a>
</strong>
</em>
</p>
<hr>
<h2>How about polonium?</h2>
<p>One potential ingredient that has been in the news in recent weeks is radioactive polonium-210, the same substance used to <a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">assassinate</a> former Russian spy Alexander Litvinenko in 2006. The Queensland government is <a href="https://www.abc.net.au/news/2023-07-26/queensland-scientists-test-vapes-for-polonium-210/102564282">now testing</a> vapes for it.</p>
<p>Polonium-210 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9207432/">can be found</a> in traditional cigarettes and other tobacco products. That’s because tobacco plants <a href="https://www.science.org/doi/abs/10.1126/science.153.3738.880">absorb it</a> and other radioactive materials from the soil, air and high-phosphate fertiliser.</p>
<p>Whether polonium-210 is found in aerosols produced by e-cigarettes remains to be seen. Although it is feasible if the glycerine in e-liquids comes from plants and similar fertilisers are used to grow them.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1684030171287019522"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">Litvinenko poisoning: polonium explained</a>
</strong>
</em>
</p>
<hr>
<h2>It’s not just the ingredients</h2>
<p>Aside from their ingredients, the materials e-cigarette devices are made from can end up in our bodies.</p>
<p><a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP2175">Toxic metals</a> and <a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP5686">related substances</a> such as arsenic, lead, chromium and nickel can be detected in both e-liquids and vapers’ urine, saliva and blood.</p>
<p>These substances can pose serious health risks (such as being carcinogenic). They can leach from several parts of an e-cigarette, including the heating coil, wires and soldered joints.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=1000&fit=clip"><img alt="Colourful, disposable vapes on a blue background" src="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chemicals from the device itself can end up in our blood, urine and saliva.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/set-colorful-disposable-electronic-cigarettes-on-2065547126">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-asked-over-700-teens-where-they-bought-their-vapes-heres-what-they-said-190669">We asked over 700 teens where they bought their vapes. Here's what they said</a>
</strong>
</em>
</p>
<hr>
<h2>That’s not all</h2>
<p>The process of heating e-liquids to create an inhalable aerosol also changes their chemical make-up to produce <a href="https://pubs.acs.org/doi/10.1021/acs.chemrestox.9b00410">degradation</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">products</a>. </p>
<p>These include:</p>
<ul>
<li><p>formaldehyde (a substance used to embalm dead bodies)</p></li>
<li><p>acetaldehyde (a key substance that contributes to a hangover after drinking alcohol)</p></li>
<li><p>acrolein (used as a chemical weapon in the first world war and now used as a herbicide).</p></li>
</ul>
<p>These chemicals are <a href="https://www.mdpi.com/2305-6304/10/12/714">often detected</a> in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6129974">e-cigarette samples</a>. However due to different devices and how the samples are collected, the <a href="https://ehjournal.biomedcentral.com/articles/10.1186/s12940-017-0249-x">levels measured</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">vary widely</a> between studies.</p>
<p>Often, the levels are very low, leading to proponents of vaping arguing e-cigarettes are far safer than tobacco smoking. </p>
<p>But this argument does not acknowledge that many e-cigarette users (particularly adolescents) <a href="https://www.tobaccoinaustralia.org.au/chapter-18-e-cigarettes/18-3-extent">were or are not cigarette smokers</a>, meaning a better comparison is between e-cigarette use and breathing “fresh” air. </p>
<p>An e-cigarette user is undoubtedly exposed to more toxins and harmful substances than a non-smoker. People who buy tobacco cigarettes are also confronted with a plethora of warnings about the hazards of smoking, while vapers generally are not.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sex-and-lies-are-used-to-sell-vapes-online-even-we-were-surprised-at-the-marketing-tactics-we-found-200446">Sex and lies are used to sell vapes online. Even we were surprised at the marketing tactics we found</a>
</strong>
</em>
</p>
<hr>
<h2>How about labelling?</h2>
<p>This leads to another reason why it’s impossible to tell what is in vapes – the lack of information, including warnings, <a href="https://www.legislation.gov.au/Details/F2021L00595">on the label</a>.</p>
<p>Even if labels are present, they don’t always reflect what’s in the product. Nicotine concentration of e-liquids is often quite different to what is on the label, and “nicotine-free” e-liquids often <a href="https://journal.chestnet.org/article/S0012-3692(20)30134-3/fulltext">contain nicotine</a>.</p>
<p>Products are also labelled with generic flavour names such as “berry” or “tobacco”. But there is no way for a user to know what chemicals have been added to make those “berry” or “tobacco” flavours or the changes in these chemicals that may occur with heating and/or interacting with other ingredients and the device components. “Berry” <a href="https://tobaccocontrol.bmj.com/content/30/2/185">flavour</a> alone could be made from <a href="https://tobaccocontrol.bmj.com/content/tobaccocontrol/suppl/2020/02/10/tobaccocontrol-2019-055447.DC1/tobaccocontrol-2019-055447supp001_data_supplement.pdf">more than 35</a> different chemicals. </p>
<p>Flavouring chemicals may be “food grade” or classified as safe-to-eat. However mixing them into e-liquids, heating and inhaling them is a very different type of exposure, compared to eating them.</p>
<p>One example is benzaldehyde (an almond flavouring). When this is inhaled, it <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.9b00171">impairs</a> the <a href="https://www.sciencedirect.com/science/article/pii/S2214750023000380">immune function</a> of lung cells. This could potentially reduce a vaper’s ability to deal with other inhaled toxins, or respiratory infections. </p>
<p>Benzaldehyde is one of only <a href="https://www.legislation.gov.au/Details/F2021L00595">eight</a> banned e-liquid ingredients in Australia. The list is so short because we don’t have enough information on the health effects if inhaled of other flavouring chemicals, and their interactions with other e-liquid ingredients.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1670806592961355777"}"></div></p>
<h2>Where to next?</h2>
<p>For us to better assess the health risks of vapes, we need to learn more about:</p>
<ul>
<li><p>what happens when flavour chemicals are heated and inhaled</p></li>
<li><p>the interactions between different e-liquid ingredients</p></li>
<li><p>what other contaminants may be present in e-liquids</p></li>
<li><p>new, potentially harmful, substances in e-cigarettes.</p></li>
</ul>
<p>Finally, we need to know more about how people use e-cigarettes so we can better understand and quantify the health risks in the real world.</p><img src="https://counter.theconversation.com/content/210462/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Larcombe has previously received funding for e-cigarette research from the National Health and Medical Research Council, Lung Foundation Australia, Minderoo Foundation, Health Department of Western Australia and Asthma Foundation of Western Australia. The funders played no role in the conduct of the research. He is also a member of the Australian Council on Smoking and Health (ACOSH).</span></em></p>It’s not just the ingredients we should be concerned about. The devices themselves release chemicals that end up in our blood and urine.Alexander Larcombe, Associate Professor and Head of Respiratory Environmental Health, Telethon Kids InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2101702023-08-09T12:32:17Z2023-08-09T12:32:17ZAI can help forecast air quality, but freak events like 2023’s summer of wildfire smoke require traditional methods too<figure><img src="https://images.theconversation.com/files/541336/original/file-20230805-83673-xiqg41.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3494%2C2331&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Thick smoke rolling in from Canada's 2023 wildfires was a wakeup call for several cities.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/people-wear-masks-as-they-wait-for-the-tramway-to-roosevelt-news-photo/1258511415">Eduardo Munoz Alvarez/Getty Images</a></span></figcaption></figure><p>Wildfire smoke from <a href="https://twitter.com/_HannahRitchie/status/1685583683707682816">Canada’s extreme fire season</a> has left a lot of people thinking about air quality and wondering what to expect in the days ahead.</p>
<p>All air contains gaseous compounds and small particles. But as air quality gets worse, these gases and particles can <a href="https://theconversation.com/extreme-heat-and-air-pollution-can-be-deadly-with-the-health-risk-together-worse-than-either-alone-187422">trigger asthma</a> and <a href="https://theconversation.com/wildfire-smoke-can-harm-human-health-even-when-the-fire-is-burning-hundreds-of-miles-away-a-toxicologist-explains-why-206057">exacerbate heart and respiratory problems</a> as they enter the nose, throat and lungs and even circulate in the bloodstream. When wildfire smoke turned New York City’s skies orange in early June 2023, <a href="https://gothamist.com/news/nyc-hospitals-saw-twice-as-many-asthma-er-visits-as-bad-air-blanketed-city">emergency room visits</a> for asthma doubled.</p>
<p>In <a href="https://www.airnow.gov/">most cities</a>, it’s easy to find a daily <a href="https://www.lung.org/clean-air/outdoors/air-quality-index">air quality index score</a> that tells you when the air is considered unhealthy or even hazardous. However, predicting air quality in the days ahead isn’t so simple.</p>
<p>I work on air quality forecasting as a <a href="https://cee.utk.edu/people/joshua-s-fu/">professor of civil and environmental engineering</a>. Artificial intelligence has improved these forecasts, but research shows it’s much more useful when paired with traditional techniques. Here’s why:</p>
<h2>How scientists predict air quality</h2>
<p>To predict air quality in the near future – a few days ahead or longer – scientists generally rely on two <a href="https://www.airnow.gov/aqi/aqi-basics/using-air-quality-index/#forecasts">main methods</a>: a <a href="https://www.airnow.gov/sites/default/files/2020-06/aq-forecasting-guidance-1016.pdf">chemical transport model</a> or a machine-learning model. These two models generate results in totally different ways.</p>
<p>Chemical transport models use lots of known chemical and physical formulas to calculate the presence and production of air pollutants. They use data from emissions inventories reported by local agencies that list pollutants from known sources, such as wildfires, traffic <a href="https://www.epa.gov/air-emissions-inventories/2020-nei-supporting-data-and-summaries">or factories</a>, and data from meteorology that provides atmospheric information, such as wind, precipitation, temperature and solar radiation.</p>
<p>These models simulate the flow and chemical reactions of the air pollutants. However, their simulations involve multiple variables with huge uncertainties. Cloudiness, for example, changes the incoming solar radiation and thus the photochemistry. This can make the results less accurate.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows many yellow dots through the Midwest. in particular, where wildfire smoke has been blowing in from Canada." src="https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541950/original/file-20230809-15-9ddhgg.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The EPA’s AirNow air pollution forecasts use machine learning. During wildfire events, a smoke-transport and dispersion model helps to simulate the spread of smoke plumes. This map is the forecast for Aug. 9, 2023. Yellow indicates moderate risk; orange indicates unhealthy air for sensitive groups.</span>
<span class="attribution"><a class="source" href="https://gispub.epa.gov/airnow/index.html">AirNow.gov</a></span>
</figcaption>
</figure>
<p>Machine-learning models instead learn patterns over time from historical data to predict future air quality for any given region, and then apply that knowledge to current conditions to predict the future. </p>
<p>The downside of machine-learning models is that they do not consider any chemical and physical mechanisms, as chemical transport models do. Also, the accuracy of machine-learning projections under extreme conditions, such as heat waves or wildfire events, can be off if the models weren’t trained on such data. So, while machine-learning models can show where and when high pollution levels are most likely, such as during rush hour near freeways, they generally cannot deal with more random events, like wildfire smoke blowing in from Canada. </p>
<h2>Which is better?</h2>
<p>Scientists have determined that neither model is accurate enough on its own, but using the <a href="https://doi.org/10.1016/j.atmosenv.2022.118961">best attributes of both</a> models together <a href="https://doi.org/10.1016/j.envint.2023.107969">can help better predict the quality</a> of the air we breathe. </p>
<p>This combined method, known as the machine-learning – measurement model fusion, or ML-MMF, has the ability to provide science-based predictions with <a href="https://doi.org/10.1016/j.envint.2023.107969">more than 90% accuracy</a>. It is based on known physical and chemical mechanisms and can simulate the whole process, from the air pollution source to your nose. Adding satellite data can help them inform the public on both air quality safety levels and the direction pollutants are traveling with greater accuracy. </p>
<p>We recently <a href="https://doi.org/10.1016/j.envint.2023.107969">compared predictions from all three models</a> with actual pollution measurements. The results were striking: The combined model was 66% more accurate than the chemical transport model and 12% more accurate than the machine-learning model alone.</p>
<p>The chemical transport model is still the most common method used today to predict air quality, but applications with machine-learning models are becoming more popular. The regular <a href="https://gispub.epa.gov/airnow/index.html">forecasting method</a> used by the U.S. Environmental Protection Agency’s <a href="https://www.airnow.gov/">AirNow.gov</a> relies on machine learning. The site also compiles air quality forecast results from state and local agencies, most of which use <a href="https://www.epa.gov/cmaq">chemical transport</a> <a href="https://www.camx.com/">models</a>.</p>
<p>As information sources become more reliable, the combined models will become more accurate ways to forecast hazardous air quality, particularly during unpredictable events like wildfire smoke.</p><img src="https://counter.theconversation.com/content/210170/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joshua S. Fu received funding from U. S. EPA for wildfire and human health studies. </span></em></p>Air quality forecasting is getting better, thanks in part to AI. That’s good, given the health impact of air pollution. An environmental engineer explains how systems warn of incoming smog or smoke.Joshua S. Fu, Chancellor's Professor in Engineering, Climate Change and Civil and Environmental Engineering, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2096662023-07-18T12:29:03Z2023-07-18T12:29:03Z‘Zombie fires’ in the Arctic: Canada’s extreme wildfire season offers a glimpse of new risks in a warmer, drier future<figure><img src="https://images.theconversation.com/files/537392/original/file-20230713-27-vbtite.jpg?ixlib=rb-1.1.0&rect=19%2C13%2C4230%2C2479&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Thick smoke rises from a peat bog fire in June 2023.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/june-2023-mecklenburg-western-pomerania-g%C3%B6ldenitz-heavy-news-photo/1258500964">Bernd Wüstneck/picture alliance via Getty Images</a></span></figcaption></figure><p>The blanket of wildfire smoke that spread across large parts of the U.S. and Canada in 2023 was a wake-up call, showing what climate change could feel like in the near future for millions of people. Apocalyptic orange skies and air pollution levels that <a href="https://theconversation.com/wildfire-smoke-can-harm-human-health-even-when-the-fire-is-burning-hundreds-of-miles-away-a-toxicologist-explains-why-206057">force people indoors</a> only tell part of the story, though. </p>
<p>As global temperatures rise, fires are also spreading farther north and into the Arctic. These fires aren’t just burning in trees and grasses. <a href="https://doi.org/10.1126/science.abn9768">New research</a> on the exceptional Arctic <a href="https://www.nytimes.com/2022/11/03/climate/siberia-fires-climate-change.html">fire seasons</a> of 2019 and 2020 points to fires moving into the ground as well.</p>
<p>These underground fires are known as “zombie fires,” and there are a number of reasons to worry about the trend.</p>
<figure class="align-center ">
<img alt="A volunteer with no mask or protective gear holds a fire hose as he fights an underground fire in a peat bog. The open bog is behind him, rimmed by forest." src="https://images.theconversation.com/files/537393/original/file-20230713-19-xbzaqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537393/original/file-20230713-19-xbzaqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537393/original/file-20230713-19-xbzaqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537393/original/file-20230713-19-xbzaqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537393/original/file-20230713-19-xbzaqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537393/original/file-20230713-19-xbzaqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537393/original/file-20230713-19-xbzaqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A volunteer fights ‘zombie’ peat fires in Siberia in 2020, a year when an estimated 100,000 square miles of forest, grassland and peatland burned, according to an International Association of Wildland Fire analysis.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/local-activist-extinguishes-a-peat-fire-in-a-suzunsky-news-photo/1228677175">Alexander Nemenov / AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>First, as the organic-rich Arctic soils dry up because of changing climate conditions, they can burn slowly and release vast amounts of smoke into the atmosphere.</p>
<p>Second, soil fires that spread underground are <a href="https://www.cbc.ca/news/canada/edmonton/wildfires-peat-challenge-alberta-firefighters-1.6850347">harder for firefighters to tame and extinguish</a>, thus demanding more resources for longer periods of time. Firefighters in Alberta, Canada, where carbon-rich peatlands are common, have been dealing with fires smoldering to depths dozens of feet underground in 2023. Because peat fires <a href="https://srd.web.alberta.ca/edson-area-update">can make the ground unstable</a>, using heavy equipment to excavate the fire areas also becomes risky.</p>
<p>Finally, these soil fires <a href="https://www.nationalgeographic.com/environment/article/zombie-fires-in-the-arctic-are-linked-to-climate-change">don’t die easily</a>. <a href="https://doi.org/10.1038/s41586-021-03437-y">Recent research</a> finds that Arctic soil fires can smolder through the winter and reignite during early spring when temperatures rise, hence the nickname “zombie fires.”</p>
<h2>The Arctic is increasingly flammable</h2>
<p>Wildfires have been a natural part of northern forest and tundra ecosystems for thousand of years. However, the <a href="https://doi.org/10.1126/science.abn9768">severity, frequency and types</a> of wildfires in northern and Arctic regions have changed in recent decades.</p>
<p>One major culprit is the rising temperature: The Arctic is warming nearly four times faster than the rest of the world, a phenomenon known as <a href="https://doi.org/10.1038/s43247-022-00498-3">Arctic amplification</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Na58YnwLz2s?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A visualization of temperature changes compared with the 1951-1980 average shows the Arctic warming significantly faster than much of the world.</span></figcaption>
</figure>
<p>While governing bodies that are working to curtail the pace of climate change worry about exceeding a 1.5-degree Celsius (2.7-degree Fahrenheit) threshold globally, the Arctic has already exceeded a 2 C (3.6 F) increase compared with pre-industrial times. That rise in temperature brings with it a number of changes to the environment that make the forest and tundra more susceptible to burning, for longer, and in more extensive ways than just a few decades ago.</p>
<p>Among the changing conditions that favor wildfires are changes in atmospheric circulation that create periods of extreme heat, dry out vegetation and <a href="https://doi.org/10.1126/science.abn9768">reduce moisture in soils</a>, and, importantly, lead to more <a href="https://doi.org/10.1088/1748-9326/ac6311">frequent lightning strikes</a> that can spark blazes.</p>
<p>Although lightning remains infrequent at very high latitudes, it is <a href="https://doi.org/10.1088/1748-9326/ac6311">expected to increase</a> and expand over <a href="https://doi.org/10.1126/science.abn9768">larger territories into the far north</a> as the climate warms and generates more storms that can produce lightning. In 2022, <a href="https://theconversation.com/alaska-on-fire-thousands-of-lightning-strikes-and-a-warming-climate-put-alaska-on-pace-for-another-historic-fire-season-186453">thousands of lightning strikes</a> help sparked one of Alaska’s worst fire seasons on record.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows Siberia is largely peatland, as are large parts of Canada." src="https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=320&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=320&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=320&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=402&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=402&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537155/original/file-20230712-26-87x7vx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=402&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A map shows peatlands and peat-heavy soils around the world.</span>
<span class="attribution"><a class="source" href="https://wedocs.unep.org/handle/20.500.11822/37571;jsessionid=CA7F7C05707AD8CDDD0D10E957C4A38B">United Nations Environment Programme</a></span>
</figcaption>
</figure>
<p>As the Arctic warms and fires move farther northward, peat soils rich in dead plant material <a href="https://www.nasa.gov/feature/goddard/2019/nasa-studies-how-arctic-wildfires-change-the-world">burn at an accelerated rate</a>. </p>
<p>The burning peat also removes the layer insulating permafrost, the region’s frozen carbon-rich soil. Northern ecosystems store <a href="https://www.reuters.com/graphics/CLIMATE-CHANGE/WILDFIRE-EMISSIONS/zjvqkrwmnvx/index.html">twice as much carbon</a> in their peat and permafrost as the atmosphere, and both are increasingly vulnerable to fire.</p>
<p>About <a href="https://doi.org/10.1126/science.abn9768">70% of recorded area of Arctic peat</a> affected by burning over the past 40 years occurred in the last eight years, and 30% of it was in 2020 alone, showing the acceleration. </p>
<h2>What is a zombie fire?</h2>
<p>Most people picture wildfires as catastrophic flames consuming trees and grasses. Ground fires, on the other hand, do not flame but burn more slowly and have the tendency to spread deep into the ground and spread laterally. </p>
<p>The result is that ground-smoldering fires are not only less visible, but they are also less accessible and require <a href="https://www.cbc.ca/news/canada/edmonton/wildfires-peat-challenge-alberta-firefighters-1.6850347">digging up and dousing</a> with lots of water. </p>
<figure class="align-center ">
<img alt="Two people point aim a hose at smoldering peat in an area surrounded by trees." src="https://images.theconversation.com/files/537394/original/file-20230713-16392-weoeqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537394/original/file-20230713-16392-weoeqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=366&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537394/original/file-20230713-16392-weoeqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=366&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537394/original/file-20230713-16392-weoeqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=366&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537394/original/file-20230713-16392-weoeqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537394/original/file-20230713-16392-weoeqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537394/original/file-20230713-16392-weoeqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fighting peat fires is difficult and dangerous. Peat fires can destabilize the ground, making it hard to bring in machinery.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/greenpeace-and-local-activists-extinguish-a-peat-fire-in-a-news-photo/1228677050">Alexander Nemenov / AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>These smoldering fires also produce more smoke because of their lower temperature of combustion. Ultra-fine particles in smoke are <a href="https://doi.org/10.1038/s41467-021-21708-0">particularly harmful</a> to the respiratory and cardiovascular systems and can be carried far and wide by winds.</p>
<p>Because of the slow combustion process and the abundance of fuel in the form of carbon and oxygen, smoldering ground fires can also <a href="https://doi.org/10.1016/j.coesh.2021.100296">burn for months and sometimes years</a>. They have been shown to “<a href="https://doi.org/10.1038/s41586-021-03437-y">overwinter</a>,” persisting through the cold season to reemerge in the warm, dry season. During the <a href="https://www.nature.com/articles/d41586-020-02568-y">2019-2020 fire season in Siberia</a>, <a href="https://www.nytimes.com/2021/05/19/climate/climate-change-zombie-forest-fires.html">zombie fires</a> were blamed for rekindling fires the following year.</p>
<p>Some of these ground fires can become so massive that they release smoke plumes that cover vast geographical regions. In 1997, peat fires in Indonesia sent <a href="https://doi.org/10.1186/s12940-022-00872-w">dangerous levels of smoke</a> across Southeast Asia and parts of Australia and <a href="https://doi.org/10.1038/nature01131">increased carbon emissions</a>. They were ignited by slash-and-burn activities to plant palm plantations and amplified by drought conditions during a severe El Niño event.</p>
<figure class="align-center ">
<img alt="A large area of pollution shows in colors covering much of the Indian Ocean, including touch India, covering Indonesia and reaching Australia." src="https://images.theconversation.com/files/537154/original/file-20230712-23-12el1r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537154/original/file-20230712-23-12el1r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537154/original/file-20230712-23-12el1r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537154/original/file-20230712-23-12el1r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537154/original/file-20230712-23-12el1r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537154/original/file-20230712-23-12el1r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537154/original/file-20230712-23-12el1r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A satellite captured the extent of smoke (white) over Indonesia and the Indian Ocean on Oct. 22, 1997. Green, yellow and red reflect increasing amounts of ozone, or smog.</span>
<span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/1260/nasa-satellite-tracks-hazardous-smoke-and-smog-partnership">NASA GSFC Scientific Visualization Studio</a></span>
</figcaption>
</figure>
<h2>Some hope and caution from past lessons</h2>
<p>I have been studying the effects of <a href="https://pubs.acs.org/doi/10.1021/acs.est.6b02132">wildfires on air</a> and <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014gl062762">water</a>, including in the Arctic, for many years. My work and that of many colleagues, however, focus on the combustion of above-ground biomass. More work is needed to understand the full extent of zombie fires in the Arctic and their potential for carbon and smoke emissions on a large scale. One recent study conducted at a handful of Canadian sites offered some hope, suggesting underground fires there <a href="https://meetingorganizer.copernicus.org/EGU23/EGU23-17450.html">were burning more in tree roots</a> than in soil, suggesting potentially lower carbon emissions in some areas.</p>
<p>In the meantime, the continuing waves of wildfire haze in Canada and the U.S. are a reminder of the impact of these fires. </p>
<p>More regions will need help from trained firefighters, meaning sharing firefighting resources. Canada has seen an <a href="https://www.theguardian.com/world/2023/jul/07/canada-wildfires-summer-weather-temps">unprecedented level of international fire support</a> in 2023. Best practices for safely fighting zombie fires are also needed, along with better public education about the health risks of wildfire smoke.</p>
<p>As a society, we are learning to live with some of the effects of climate change, but the risks are rising around the world.</p><img src="https://counter.theconversation.com/content/209666/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patrick Louchouarn receives funding from NASA-USDA (Carbon Cycle Science Program); Welch Foundation (student support); NSF-REU</span></em></p>Large stretches of the Arctic are carbon-rich peat bogs. As the region warms and dries, lightning strikes can spark underground fires that can burn for years.Patrick Louchouarn, Professor of Earth Sciences, The Ohio State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2081532023-06-22T12:30:35Z2023-06-22T12:30:35ZTo see how smoke affects endangered orangutans, we studied their voices during and after massive Indonesian wildfires<figure><img src="https://images.theconversation.com/files/533199/original/file-20230621-11493-h6xfhj.jpeg?ixlib=rb-1.1.0&rect=7%2C0%2C4861%2C3080&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An adult male orangutan contemplates his next move in haze produced by Indonesia's 2015 wildfires.</span> <span class="attribution"><span class="source">Wendy Erb</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Bornean orangutans are one of three orangutan species, all <a href="https://www.iucnredlist.org/search?query=orangutan&searchType=species">critically endangered</a>. They thrive in carbon-rich peat swamp forests on the Indonesian island of Borneo. These habitats are also the sites of massive wildfires.</p>
<p>Indonesian wildfires in 2015 caused some of the <a href="https://doi.org/10.3390/rs10040495">worst fire-driven air pollution</a> ever recorded. The fires were driven by an <a href="https://www.noaa.gov/understanding-el-nino#">El Niño climatic cycle</a>, which <a href="https://www.nasa.gov/feature/Goddard/2016/severe-2015-indonesian-fire-season-linked-to-el-nino-drought">caused especially dry weather</a> in the region.</p>
<p>Compared to other wildfires, peatland fires smolder underground and produce exceptionally high levels of hazardous gases and particulate matter – a leading cause of <a href="https://theconversation.com/wildfire-smoke-can-harm-human-health-even-when-the-fire-is-hundreds-of-miles-away-a-toxicologist-explains-why-206057">global pollution-related deaths and illnesses</a>. </p>
<p>Orangutans are well known as an “<a href="https://www.britannica.com/science/indicator-species">indicator species</a>” – one that can serve as a proxy for the health of an ecosystem. Changes in their environments often cause conspicuous changes in the apes’ health and behavior. Frequent and persistent exposure to toxic smoke could have severe consequences for orangutans and other wildlife.</p>
<p>Toxic air pollution also poses serious health and safety risks for researchers. However, <a href="https://doi.org/10.1093/biosci/biy147">remote sensing techniques</a>, such as satellite images, GPS data and acoustic monitoring, are increasingly popular ways to track wildlife populations and see how creatures respond to changes in their environments.</p>
<p>I have studied the behavior, ecology and acoustic communication of <a href="https://scholar.google.com/citations?user=ykHYzwEAAAAJ&hl=en">wild primates in Indonesia</a> since 2005. In a new study, my co-authors and I investigated how wild orangutans in Borneo were affected by toxic emissions from Indonesia’s 2015 peatland wildfires – by <a href="https://doi.org/10.1016/j.isci.2023.107088">studying their voices</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/cBnbLJ5TzvE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Indonesia’s degraded peatlands are tinderboxes that can easily ignite with several weeks of dry weather.</span></figcaption>
</figure>
<h2>Smoke exposure poses long-term risks</h2>
<p>Around the world, <a href="https://www.unep.org/news-and-stories/press-release/number-wildfires-rise-50-2100-and-governments-are-not-prepared">wildfires are on the rise</a>. They often produce a thick blanket of haze that contains diverse hazardous gases and particulate matter, or PM. Most recently, smoke from Canadian wildfires blanketed the U.S. East Coast and Midwest in early June 2023, <a href="https://www.youtube.com/watch?v=kLN3kBthm9Y">turning skies orange</a> and triggering public health alerts.</p>
<p>Studies have shown that <a href="https://doi.org/10.1016/j.envres.2014.10.015">human health risks from wildfire smoke</a> include respiratory and cardiovascular illnesses, systemic inflammation and premature death. Much less is known about how smoke affects wildlife, but in a pair of studies published <a href="https://doi.org/10.1016/j.reprotox.2021.08.005">in 2021</a> <a href="https://doi.org/10.1038/s41467-022-29436-9">and 2022</a>, scientists at the <a href="https://cnprc.ucdavis.edu/">California National Primate Research Center</a> reported alarming findings.</p>
<p>After less than two weeks of exposure to high concentrations of particulate matter – in particular, ultrafine particles measuring less than 2.5 microns in diameter, which are known as PM2.5 – captive <a href="https://www.britannica.com/animal/rhesus-monkey">rhesus macaques</a> suffered a spike in pregnancy loss. What’s more, surviving fetuses and infants suffered long-term effects on lung capacity, immune responses, inflammation, cortisol levels, behavior and memory. </p>
<p>During Indonesia’s 2015 fires, Borneo’s air had particulate matter concentrations nearly an order of magnitude higher than the levels in these studies. This made the potential implications for people and wildlife who gasped through Indonesia’s wildfire smoke for nearly two months extremely worrying.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Fire and smoke rise from charred ground near a scorched tree." src="https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533205/original/file-20230621-17-x1066c.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A wildfire blazes in a small rubber tree garden along the border of the Tuanan study area during Indonesia’s 2015 wildfires.</span>
<span class="attribution"><span class="source">Wendy Erb</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Orangutans in the haze</h2>
<p>I was studying wild orangutans in the forests of Indonesian Borneo when the 2015 fires started. My colleagues and I at the <a href="https://coreborneo.com/tuanan-research-station/">Tuanan Orangutan Research Station</a> tracked local fires and patrolled nearby hot spots to assess the risk of fire spreading to our research area. </p>
<p>Wearing N-95 masks, we continued to monitor orangutans in hopes of learning how the animals were coping with encroaching fires and thick smoke. A few weeks into the fire season, I noticed a difference in the sound of the males’ “<a href="https://wildambience.com/wildlife-sounds/orangutan/">long call</a>,” which was the focus of <a href="https://wendyerb.weebly.com/projects.html">my research</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/cRJoooWf5vU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An adult male Bornean orangutan’s long call.</span></figcaption>
</figure>
<p>Long calls are booming vocalizations that can be heard over distances of more than half a mile (1 kilometer). Orangutans are semi-solitary and live in dispersed communities, so these calls serve an important social role. Adult males make them to advertise their prowess to listening females in the area and to scare off any eavesdropping rival males. A couple of weeks after the smoke had appeared, I thought these males sounded raggedy – a little like humans who smoke a lot. </p>
<p>We observed the orangutans for 44 days during the fires, until large blazes encroached on our study area. At that point, we stopped the study to help extinguish the blazes with local firefighting teams and other government and nonprofit groups. Fires burned in our study area for three weeks.</p>
<p>Using data that we collected before, during and after the fires, I led an analysis of this Bornean orangutan population’s <a href="https://doi.org/10.1016/j.isci.2023.107088">behavior and health</a>. My co-authors and I found that in the weeks after the fires, the apes reduced their activities – resting more and traveling shorter distances – and consumed more calories than normal. </p>
<p>But although they were eating more and moving less, we found by collecting and testing the apes’ urine that they were <a href="https://doi.org/10.1038/s41598-018-25847-1">still burning stored fat</a> – a sign that they somehow were using up more energy. We hypothesized that the cause <a href="https://my.clevelandclinic.org/health/symptoms/21660-inflammation#:%7E:text=The%20most%20common%20reasons%20for,from%20an%20infection%20or%20injury">might be inflammation</a> – the swelling, fever, pain and fatigue that human and animal bodies experience in response to infection or injury. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An orangutan reclines in a tree surrounded by haze." src="https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=380&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=380&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=380&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533206/original/file-20230621-20-pixdob.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Otto, one of four adult male orangutans observed and recorded for this research, takes a midday smoky nap during Indonesia’s 2015 wildfires.</span>
<span class="attribution"><span class="source">Wendy Erb</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Sentinel sounds</h2>
<p>Studies have shown that when humans are exposed to particulate matter, they can experience inflammation, both in their <a href="https://doi.org/10.1097/JOM.0000000000001775">respiratory tracts</a> and <a href="https://doi.org/10.1164/ajrccm.164.5.2010160">throughout their bodies</a>. We wanted to know whether inhaling wildfire smoke would cause vocal changes in orangutans, just as inhaling cigarette smoke does in humans.</p>
<p>For this study, my co-authors and I carefully analyzed more than 100 sound recordings of four male orangutans that we followed before and during the fires to measure their vocal responses to wildfire smoke. Research has shown that a suite of vocal features – including <a href="https://www.asha.org/practice-portal/clinical-topics/voice-disorders/#collapse_2">pitch, vocal harshness or hoarseness, and shaky voice</a> – reflects the underlying health and condition of both human and nonhuman animals. We were looking for acoustic clues about how this toxic air might be affecting the orangutans. </p>
<p>During the fires and for several weeks after the smoke cleared, these males called less frequently than usual. Normally, orangutans call about six times a day. But during the fires, their call rate was cut in half. Their voices dropped in pitch, showing more vocal harshness and irregularities. </p>
<p>Collectively, these features of vocal quality have been linked to inflammation, stress and disease – including COVID-19 – in <a href="https://doi.org/10.1016/j.eswa.2017.04.012">human</a> and <a href="https://doi.org/10.1038/s41598-021-83614-1">nonhuman</a> animals.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CCoXocEBgiv/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Listening to vocal species</h2>
<p>Increasingly frequent and prolonged exposure to toxic smoke could have severe consequences for orangutans and other animals. Our research highlights the urgent need to understand the long-term and far-ranging effects of peatland fires in Indonesia, which is one of the <a href="https://www.cbd.int/countries/profile/?country=id">most biodiverse countries in the world</a>. </p>
<p>By uncovering the linkages between acoustic, behavioral and energetic shifts in orangutans, our study highlights a way for scientists and wildlife managers to safely monitor the health of orangutans and other animals. Using <a href="https://www.birds.cornell.edu/ccb/passive-acoustic-monitoring/">passive acoustic monitoring</a> to study vocally active indicator species, like orangutans, could unlock critical insights into wildfire smoke’s effects on wildlife populations worldwide.</p><img src="https://counter.theconversation.com/content/208153/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wendy M. Erb is affiliated with the American Society of Primatologists; the Borneo Nature Foundation; and Primate Conservation, Inc. She has received research funding from the American Association of University Women; the American Institute for Indonesian Studies; the American Association of Biological Anthropologists; the American Society of Primatologists; the British Academy; the Conservation, Food, and Health Foundation; Conservation International; Cornell University; Disney Conservation Fund; the Fulbright Program; the International Society of Primatologists; and the National Science Foundation. </span></em></p>Orangutans are vocal animals, so analyzing their calls during events like wildfires can indicate how smoke is affecting their health.Wendy M. Erb, Postdoctoral Associate in Conservation Bioacoustics, Cornell UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2076762023-06-14T12:34:45Z2023-06-14T12:34:45ZWildfire smoke and dirty air are also climate change problems: Solutions for a world on fire<figure><img src="https://images.theconversation.com/files/531803/original/file-20230613-27-deg09.jpg?ixlib=rb-1.1.0&rect=1285%2C457%2C6513%2C4560&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">People wore face masks as wildfire smoke from Canada turned New York City's sky orange on June 7, 2023.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/person-wears-a-face-mask-as-smoke-from-wildfires-in-canada-news-photo/1258513476">Angela Weiss/AFP via Getty Images</a></span></figcaption></figure><p>As the eastern U.S. and Canada reeled from <a href="https://theconversation.com/wildfire-smoke-can-harm-human-health-even-when-the-fire-is-hundreds-of-miles-away-a-toxicologist-explains-why-206057">days of thick wildfire smoke</a> in early June 2023, millions of people faced the reality of climate change for the first time. Shocking images of New York under <a href="https://www.youtube.com/watch?v=kLN3kBthm9Y">apocalyptic orange skies</a> left many people glued to <a href="https://gispub.epa.gov/airnow/?showgreencontours=false">air quality indices</a> and wondering whether it was safe to go outside.</p>
<p>What they might not realize is that the air many of them breathe isn’t healthy even when wildfire smoke isn’t filling the sky. </p>
<p>In fact, the air that <a href="https://www.who.int/news/item/04-04-2022-billions-of-people-still-breathe-unhealthy-air-new-who-data">99% of the world’s population</a> breathes is not safe, according to the World Health Organization.</p>
<p>Air pollution is everywhere, in cities and in the countryside, visible and invisible. It kills an estimated 7 million to 10 million people a year, <a href="https://www.ccacoalition.org/en/news/cleaning-air">taking 2.2 years off global average life expectancy</a>. Worldwide, that’s a combined 17 billion life years. There is <a href="https://doi.org/10.1073/pnas.1803222115">growing evidence</a> that even low levels of air pollutants damage the human body, increasing the risk of <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">cardiovascular and respiratory illnesses</a> like asthma and emphysema, heart disease and lung cancer.</p>
<p>Because of its generally local and immediate impacts on human health, air pollution is often not talked about in the same sentence as climate change. Yet air pollution can be harmful for the planet, too. Nearly all actions to reduce climate change lead to improved air quality, and there are many ways to clean up air pollution that provide climate benefits.</p>
<h2>A toxic relationship</h2>
<p>When people talk about reducing climate change, they often focus on carbon dioxide emissions, and for good reason. Carbon dioxide, largely from burning fossil fuels, is the <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide">largest driver of climate change</a>, and it lingers in the atmosphere for centuries, warming the planet.</p>
<p>But there are other pollution sources that harm the climate, and reducing them can have a much faster impact on global warming in the short term.</p>
<p><a href="https://www.ccacoalition.org/en/slcps/black-carbon">Black carbon</a> – the tiny particles in the air from wildfires and also from vehicles – along with <a href="https://theconversation.com/biden-announces-a-sweeping-methane-plan-heres-why-cutting-the-greenhouse-gas-is-crucial-for-protecting-climate-and-health-168220">methane</a>, <a href="https://theconversation.com/cooling-conundrum-hfcs-were-the-safer-replacement-for-another-damaging-chemical-in-refrigerators-and-air-conditioners-with-a-treaty-now-phasing-them-out-whats-next-191172">hydrofluorocarbons</a> and <a href="https://www.ccacoalition.org/en/slcps/tropospheric-ozone">tropospheric ozone</a>, are known as <a href="https://www.ccacoalition.org/en/science-resources">short-lived climate pollutants</a>. They account for <a href="https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf">around half of today’s global warming</a>, contributing to rising sea levels and more frequent and extreme climatic events, including the devastating wildfires we’re increasingly seeing across the world.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1666592756456738816"}"></div></p>
<p>In addition, these pollutants have disastrous impacts on human health, food supplies and <a href="https://www.unep.org/news-and-stories/statements/statement-chief-scientists-2022-international-day-clean-air-blue-skies">biodiversity</a>.</p>
<p>Methane, for example, is a <a href="https://www.ccacoalition.org/en/news/methane%E2%80%99s-links-respiratory-diseases-strengthens-case-its-rapid-reduction">key precursor to ground-level ozone</a>, which is created by <a href="https://www.epa.gov/ground-level-ozone-pollution/ground-level-ozone-basics">reactions between natural and human-made compounds</a> in the presence of sunlight. It kills an estimated 1 million people per year and also harms vital global crops, including cotton, peanuts, soybean, winter wheat, rice and corn. Crop losses due to ozone total an estimated <a href="https://www.ccacoalition.org/en/slcps/tropospheric-ozone">79 million to 121 million tons, worth US$11 billion to $18 billion annually</a>.</p>
<p>Black carbon comes from burning wood, charcoal and crop residue, and is also in the soot from fossil fuel combustion in vehicles, especially diesel. It makes up a substantial portion of <a href="https://www.iqair.com/us/usa/new-york/new-york-city">PM2.5, the tiny particulate matter</a> in air that can penetrate <a href="https://ww2.arb.ca.gov/resources/fact-sheets/particulate-matter-and-health-fact-sheet">deep into the lungs</a>, contributing to respiratory and heart problems. Black carbon can also <a href="https://doi.org/10.1175/JCLI-D-17-0439.1">disrupt regional rainfall patterns</a>.</p>
<p>There are some types of aerosols that can lead to cooling, which means it takes time for the effect of carbon dioxide reductions to <a href="https://doi.org/10.1038/s41586-019-1554-z">catch up with the aerosol decreases</a> when phasing out coal and internal combustion engines. The rapid climate benefits of reducing short-lived climate pollutants thus also complement the slower but crucial climate benefits of decarbonization, providing much needed near-term relief from the onslaught of accelerating climate change we see around us.</p>
<h2>Solutions exist, and they aren’t rocket science</h2>
<p>These short-lived climate pollutants are <a href="https://www.ccacoalition.org/en/content/what-are-short-lived-climate-pollutants">tens to thousands of times</a> more powerful than carbon dioxide at warming the planet. The flip side is in their name: They are short-lived – they remain in the atmosphere for a few days up to a few years, considerably less time than carbon dioxide.</p>
<p>That means that reducing these pollutants can have an almost immediate impact on climate change and human health.</p>
<p><a href="https://www.ccacoalition.org/en/science-resources">Research from the United Nations</a> shows that cutting short-lived climate pollutants now could reduce projected global warming by 0.5 degrees Celsius (0.9 degrees Fahrenheit) by 2050, avoid millions of premature deaths from air pollution annually, and prevent millions of tons of annual crop losses, among other additional benefits for human and planetary well-being.</p>
<p>In short, cutting short-lived climate pollutants now alongside decarbonizing economies is the <a href="https://www.ccacoalition.org/en/science-resources">best shot</a> to meet the world’s <a href="https://unfccc.int/process-and-meetings/the-paris-agreement">goal to limit global warming</a> to 1.5 C (2.7 F) – and avoid the most dangerous impact of climate change.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration shows impacts of short-lived climate pollutants including black carbon, methane, HFCs and tropospheric ozone. Impacts include harm to climate, crops, ecosystems and human health." src="https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=443&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=443&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=443&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=556&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=556&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531809/original/file-20230613-27-vd63a9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=556&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The impacts of short-lived climate pollutants.</span>
<span class="attribution"><a class="source" href="https://www.ccacoalition.org/en/content/media-resources">Climate and Clean Air Coalition</a></span>
</figcaption>
</figure>
<p>The good news is that scientists know exactly how to do it.</p>
<p>I <a href="https://scholar.google.com/citations?user=MeraHu8AAAAJ&hl=en">worked at NASA</a> for nearly 20 years, and I can tell you that cutting these emissions is not rocket science. There are practical, technically feasible and cost-effective ways to reduce short-lived climate pollutants. For example:</p>
<ul>
<li><p>A quick way to dramatically reduce methane is to patch up leaks in oil and gas pipelines – which actually <a href="https://theconversation.com/reducing-methane-is-crucial-for-protecting-climate-and-health-and-it-can-pay-for-itself-so-why-arent-more-companies-doing-it-160423">saves companies money</a>, too.</p></li>
<li><p>Hydrofluorocarbons, often used in refrigerators and air conditioning units, can be <a href="https://theconversation.com/cooling-conundrum-hfcs-were-the-safer-replacement-for-another-damaging-chemical-in-refrigerators-and-air-conditioners-with-a-treaty-now-phasing-them-out-whats-next-191172">replaced with alternatives</a> that have low or zero global warming potential.</p></li>
<li><p>Shifting to <a href="https://theconversation.com/boosting-ev-market-share-to-67-of-us-car-sales-is-a-huge-leap-but-automakers-can-meet-epas-tough-new-standards-203663">electric vehicles</a> and helping people in developing countries transition to <a href="https://www.ccacoalition.org/en/initiatives/household-energy">clean methods of cooking</a> instead of on open fires can reduce black carbon.</p></li>
</ul>
<h2>Delaying the cleanup raises risks and costs</h2>
<p>Mitigating short-lived climate pollutants in this decade can <a href="https://doi.org/10.1073/pnas.2123536119">reduce damage due to climate change</a> over the next few decades, prevent biodiversity loss and slow melting in the Arctic. That can increase the chance of staying at least below 2 C (3.6 F) of warming through mid-century, cut the costs of meeting climate targets and achieve near-term benefits for humans and the Earth alike.</p>
<p>As wildfires rage, fueled by a warming climate, they underscore the disastrous consequences of ignoring science and continuing to power the world with fossil fuels.</p>
<p>Wildfires are not just a symptom of the worsening climate catastrophe, they are also a source that <a href="https://climate.nasa.gov/explore/ask-nasa-climate/3066/the-climate-connections-of-a-record-fire-year-in-the-us-west/">amplifies ongoing warming</a>. I hope the latest fires are a wake-up call, not just for the Americans and Canadians who are struggling to breathe and facing the loss of homes and livelihoods, but for the world. Alongside decarbonization, we have another powerful tool in our arsenal – let’s use it.</p><img src="https://counter.theconversation.com/content/207676/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Drew Shindell has received funding from the Global Methane Hub initiative and the Clean Air Task Force. </span></em></p>So much pollution goes into the air today that even without wildfire smoke, 99% of the global population breathes unhealthy air.Drew Shindell, Professor of Climate Sciences, Duke UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2073952023-06-09T20:27:12Z2023-06-09T20:27:12ZWildfire smoke FAQ: What’s happening with air quality right now and why? What are the risks? How do I protect myself short-term? What about long-term protection? Is this the ‘new normal?’<p>With wildfire smoke affecting most of North America, what are the best ways to minimize the health impacts of air pollution under climate change? Here are answers to some key questions about the ongoing air quality problems.</p>
<h2>What is happening with air quality right now?</h2>
<p>Many North Americans have never experienced local air quality as bad as it’s been this week. The <a href="https://www.bbc.com/news/world-us-canada-65856819">air quality has been poor across the most densely populated regions</a> in Canada and the United States. <a href="https://doi.org/10.1021/acs.est.2c02934">Based on analysis starting in 2006</a>, the average U.S. population exposure to wildfire smoke is one of the highest estimated, and the highest over the eastern U.S. Air pollution levels, measured by the <a href="http://www.airqualityontario.com/aqhi/">Air Quality Health Index</a> in Canada, and the Air Quality Index in the U.S., have been considered high risk across much of Canada, and the eastern U.S. </p>
<h2>What is causing the poor air quality?</h2>
<p>Climate change is contributing to <a href="https://agriculture.canada.ca/en/agricultural-production/weather/canadian-drought-monitor/current-drought-conditions">unusually hot, dry weather</a> recently experienced over much of Canada. This <a href="https://cwfis.cfs.nrcan.gc.ca/maps/fw?type=fwi">creates conditions</a> that foster haze, smog and wildfires. </p>
<p>The <a href="https://firesmoke.ca/forecasts/current/">number and extent of fires burning</a>, and prevailing winds, means that the vast majority of Canadians across the country have been at least somewhat impacted by wildfire smoke this week. Winds are pushing smoke from western fires eastward across the north and Prairies. They have, during the worst air quality, swept smoke from fires in Québec directly into the most densely populated regions of the continent, contributing to <a href="https://heatmap.news/climate/wildfire-smoke-2023-worst-history">record-breaking pollution </a>in New York. </p>
<p>Those living nearest to the fires are affected by high levels of <a href="https://www.canada.ca/en/health-canada/services/publications/healthy-living/wildfire-smoke-health.html#wildfire">harmful particles and gases</a> directly emitted by the fires. Those in downwind regions are also affected, as small particles stay suspended in air for days, and hot gases from the fires cool and condense into even more particles, forming haze and smog. </p>
<h2>What are the risks to us?</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People on benches with a bridge and city view with haze in the background" src="https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531188/original/file-20230609-686-5ze7u2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">People on the East River promenade are framed by the hazy Brooklyn waterfront skyline and the Manhattan bridge on June 8 in New York. Smoke from Canadian wildfires is affecting air quality in some of the most densely populated areas of North America.</span>
<span class="attribution"><span class="source">(AP Photo/Mary Altaffer)</span></span>
</figcaption>
</figure>
<p>The unhealthy levels of pollution we have now can impact our daily activities or affect travel due to poor visibility and haze. The current estimated cost of air pollution in Canada is $120 billion per year. The worst impacts are to human health. <a href="https://www.canada.ca/en/health-canada/services/publications/healthy-living/health-impacts-air-pollution-2021.html">Health Canada</a> estimates that air pollution is linked to more than 15,000 premature deaths in Canada every year.</p>
<p>Wildfire smoke, specifically, can cause throat irritation, coughing, headaches and can affect lung function even in healthy children. It is <a href="http://dx.doi.org/10.1289/ehp.1409277">linked to acute respiratory symptoms</a> for people with asthma and chronic obstructive pulmonary disease (COPD). Visits to doctors, emergency departments, and hospitalizations will increase. </p>
<h2>What can we do to protect ourselves in the short term?</h2>
<p>People can help protect themselves by paying attention to <a href="https://weather.gc.ca/airquality/pages/index_e.html">air quality alerts</a> and follow <a href="https://www.airnow.gov/sites/default/files/2021-03/air-quality-guide_pm_2015_0.pdf">associated guidance</a>. This guidance <a href="https://www.canada.ca/en/environment-climate-change/services/air-quality-health-index/wildfire-smoke.html">typically involves reducing exposure</a> by limiting time outdoors when pollution is severe, especially for vigorous physical activity. </p>
<p>We need more evidence on who is most susceptible groups to wildfire smoke, specifically. However, based on evidence of the effects of air pollution, children, the elderly, pregnant women, and people with asthma and COPD, among others, should follow guidance for sensitive groups, which may mean remaining indoors. </p>
<p>Outdoor air can also get inside, especially in leaky homes with open doors and windows. When inside, keep your doors and windows closed, and run filtration, such as a central HVAC or heat pump system with an air filter, or run an indoor air purifier. Keep indoor air clean by reducing sources of smoke from tobacco, wood fireplaces, cooking and candles. When outside, wearing a well-fitting N95 mask offers protection from <a href="https://doi.org/10.1038/s41370-020-00267-4">smoke particles</a>, but will not filter out harmful gases. </p>
<h2>What can we do to protect ourselves in the long term?</h2>
<p>My own research has shown that fighting climate change per our global agreement will help <a href="https://doi.org/10.1021/acs.est.8b05094">reduce the rise</a> in air pollution. So will further reductions in other sources of air pollution, along with wildfire management strategies. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/wildfire-preparedness-and-response-must-include-planning-for-unhoused-people-and-other-vulnerable-populations-206851">Wildfire preparedness and response must include planning for unhoused people and other vulnerable populations</a>
</strong>
</em>
</p>
<hr>
<p>Given, however, that wildfires — and days with poor air quality — will continue, we should also protect our most vulnerable with access to clean indoor environments. Outdoor air pollution unfairly affects <a href="https://doi.org/10.1126/sciadv.abf4491">racialized</a> and <a href="https://doi.org/10.1371/journal.pone.0192461">socio-economically disadvantaged</a> communities, which also have lower access to shelter that keeps polluted air out. </p>
<h2>Is this a ‘new normal?’</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A cityscape across water, obscured by smoky haze" src="https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531190/original/file-20230609-19-ynrpsy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Delta Hotels Bessborough in Saskatoon is photographed through thick smoke from wildfires burning across the Prairies on May 20.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Heywood Yu</span></span>
</figcaption>
</figure>
<p>Climate change has already played a role in rising wildfire risks over the last <a href="https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-11/">century</a>. Those risks are projected to further increase over parts of North America. Canadian research suggests that the conditions causing unmanageable wildfires <a href="https://doi.org/10.1088/1748-9326/aa7e6e">could more than double some risks</a> in parts of the country this century, including those currently experiencing fires. </p>
<p>Further, climate change is known to increase air pollution, both <a href="https://doi.org/10.1021/acs.est.5b01324">average</a>, and <a href="https://doi.org/10.1029/2021JD035985">extremes</a> levels. We can hope this will not be a new normal, but, to prevent that, we need to act to reduce these risks. </p>
<h2>What can we learn from this moment?</h2>
<p>This moment shows the risks we face if we do not address climate change and air quality together. We have made <a href="https://doi.org/10.1007/s00267-021-01468-9">major gains in air quality</a> in North America over the last fifty years thanks to significant reductions in emissions of air pollutants. However, those reductions are <a href="https://doi.org/10.1021/acs.est.8b05094">at risk</a> from the worsening effects of climate change.</p>
<p>This moment also shows the clear and tangible impacts of climate change on our health. Research, including <a href="https://doi.org/10.1038/nclimate2342">a study I co-authored</a>, has shown that policy to fight climate change has big benefits for air quality, and those benefits alone can exceed the entire cost of a climate policy. Climate change is also a local health issue, and the <a href="https://doi.org/10.1016/S0140-6736(15)60854-6">greatest opportunity</a> to equitably improve health of this century.</p><img src="https://counter.theconversation.com/content/207395/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Kaarina Saari receives funding from the Natural Science and Engineering Research Council of Canada, the Tri-Agency Institutional Programs, and the Royal Bank of Canada. </span></em></p>Answers to some of the most common questions about wildfire smoke, health risks and the air quality situation affecting most of North America.Rebecca Kaarina Saari, Associate Professor of Civil and Environmental Engineering, University of WaterlooLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2060572023-05-22T12:26:52Z2023-05-22T12:26:52ZWildfire smoke can harm human health, even when the fire is burning hundreds of miles away – a toxicologist explains why<figure><img src="https://images.theconversation.com/files/534623/original/file-20230628-27-qecwmv.jpg?ixlib=rb-1.1.0&rect=24%2C66%2C4001%2C2728&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wildfire smoke filled the air at Chicago's Wrigley Field on June 27, 2023.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/CanadaWildfiresAirQualityGreatLakesBaseball/e86f2c376cb040da87a614b0abdb8861/photo">AP Photo/Kim Johnson</a></span></figcaption></figure><p><em>Smoke from <a href="https://www.ciffc.ca/">more than 100 wildfires</a> burning across Canada has been rolling into North American cities far from the flames. New York City, Denver, Chicago, Minneapolis and Detroit each made the list of the <a href="https://www.iqair.com/us/world-air-quality-ranking">most polluted cities in the world</a> at times in May and June 2023 because of the fires. The smoke has triggered air quality alerts in several states.</em></p>
<p><em>We asked <a href="https://www.umt.edu/biomedical-pharmaceutical-sciences/people/faculty.php?ID=1345">Chris Migliaccio</a>, a toxicologist at the University of Montana who studies the impact of wildfire smoke on human health, about the health risks people can face when smoke blows in from distant wildfires.</em></p>
<h2>What’s in wildfire smoke that’s a problem?</h2>
<p>When we talk about air quality, we often talk about PM2.5. That’s particulate matter 2.5 microns or smaller – small enough that it can travel deep into the lungs.</p>
<p>Exposure to PM2.5 from smoke or other air pollution, such as vehicle emissions, can exacerbate health conditions like asthma and reduce lung function in ways that can worsen existing respiratory problems and even heart disease.</p>
<p>But the term PM2.5 only tells you about size, not composition – what is burning can make a significant difference in the chemistry.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of North America shows wildfire smoke from fires in Alberta and Ontario, Canada, detected strongly with poor air quality in the Great Lakes region, Northeast and Midwestern U.S." src="https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534612/original/file-20230628-19-5wd03e.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Smoke from wildfires in Canada was detected across a large part of the U.S. on June 28, 2023. Dark purple dots indicate hazardous air quality. Light purple indicates very unhealthy air; red is unhealthy; orange is unhealthy for sensitive groups; and yellow indicates moderate risk. AirNow.gov.</span>
<span class="attribution"><a class="source" href="https://fire.airnow.gov/">AirNow.gov</a></span>
</figcaption>
</figure>
<p>In the northern Rockies, where I live, most fires are fueled by vegetation, but <a href="https://doi.org/10.1289/EHP3450">not all vegetation is the same</a>. If the fire is in the wildland urban interface, manufactured fuels from homes and vehicles may also be burning, and that’s going to <a href="https://nap.nationalacademies.org/catalog/26460/the-chemistry-of-fires-at-the-wildland-urban-interface">create its own toxic chemistry</a>, as well. Chemists often talk about <a href="https://www.cdc.gov/climateandhealth/effects/wildfires.htm">volatile organic compounds</a>, (VOCs), carbon monoxide and PAHs, or <a href="https://www.cdc.gov/biomonitoring/PAHs_FactSheet.html">polycyclic aromatic hydrocarbons</a> produced when biomass and other matter burns having the potential to harm human health.</p>
<h2>How does inhaling wildfire smoke harm human health?</h2>
<p>If you have ever been around a campfire and got a blast of smoke in your face, you probably had some irritation. With exposure to wildfire smoke, you might get some irritation in the nose and throat and maybe <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021GH000578">some inflammation</a>. If you’re healthy, your body for the most part will be able to handle it. </p>
<p>As with a lot of things, the dose makes the poison – almost anything can be harmful at a certain dose.</p>
<p>Generally, cells in the lungs called <a href="https://www.ncbi.nlm.nih.gov/books/NBK513313/">alveolar macrophages</a> will pick up the particulates and clear them out – at reasonable doses. It’s when the system gets overwhelmed that you can have a problem.</p>
<figure class="align-right ">
<img alt="Illustration of a small section of lungs showing the alveoli and, within the alveoli, a close up of a microphage" src="https://images.theconversation.com/files/527320/original/file-20230519-27-a7wgjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/527320/original/file-20230519-27-a7wgjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=914&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527320/original/file-20230519-27-a7wgjx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=914&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527320/original/file-20230519-27-a7wgjx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=914&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527320/original/file-20230519-27-a7wgjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1148&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527320/original/file-20230519-27-a7wgjx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1148&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527320/original/file-20230519-27-a7wgjx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1148&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Where macrophages are found in alveoli, the tiny air sacs in the lungs.</span>
</figcaption>
</figure>
<p>One concern is that smoke can <a href="https://doi.org/10.1038/s41598-018-31459-6">suppress macrophage function</a>, altering it enough that you become more susceptible to respiratory infection. A colleague who looked at lag time in the effect of wildfire smoke exposure found an <a href="https://doi.org/10.1016/j.envint.2020.105668">increase in influenza cases after a bad fire season</a>. Studies in developing countries have also found increases in <a href="https://doi.org/10.1016/j.atmosenv.2022.119055">respiratory infections</a> with people who are <a href="http://dx.doi.org/10.1136/thx.2010.147884">cooking on open fires</a> in homes.</p>
<p>The stress of an inflammatory response can also exacerbate existing health problems. Being exposed to wood smoke won’t independently cause someone to have a heart attack, but if they have underlying risk factors, such as significant plaque buildup, the added stress can increase the risk.</p>
<p>Researchers are also studying potential <a href="https://theconversation.com/breathing-wildfire-smoke-can-affect-the-brain-and-sperm-as-well-as-the-lungs-166548">effects on the brain</a> and <a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP10498">nervous system</a> from <a href="https://www.epa.gov/isa/integrated-science-assessment-isa-particulate-matter">inhaled particulate matter</a>.</p>
<h2>When smoke blows over long distances, does its toxicity change?</h2>
<p>We know that the chemistry of wildfire smoke changes. The longer it’s in the atmosphere, the more the <a href="https://theconversation.com/wildfire-smoke-changes-dramatically-as-it-ages-and-that-matters-for-downwind-air-quality-heres-what-we-learned-flying-through-smoke-plumes-151671">chemistry will be altered</a> by ultraviolet light, but we still have <a href="http://doi.org/10.1016/j.etap.2017.08.022">a lot to learn</a>.</p>
<figure class="align-center ">
<img alt="A woman walks past the New York Stock Exchange building in the Wall Street district of New York. The sky is yellow-orange with wildfire smoke, a sky color common in apocalyptic films." src="https://images.theconversation.com/files/534624/original/file-20230628-17-7l230z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534624/original/file-20230628-17-7l230z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534624/original/file-20230628-17-7l230z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534624/original/file-20230628-17-7l230z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534624/original/file-20230628-17-7l230z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534624/original/file-20230628-17-7l230z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534624/original/file-20230628-17-7l230z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wildfire smoke from Canada turned the skies in New York City an apocalyptic shade of orange on June 7, 2023.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/CanadaWIldfiresPhotoGallery/1601ea44e9bb4515ba755b4f6a7d5fa9/photo">AP Photo/J. David Ake</a></span>
</figcaption>
</figure>
<p>Researchers have found that there seems to be a higher level of oxidation, so oxidants and free radicals are being generated the longer smoke is in the air. The specific health effects aren’t yet clear, but there’s some indication that more exposure leads to <a href="https://doi.org/10.1155/2017/8416763">greater health effects</a>.</p>
<p>The supposition is that more <a href="https://ec.europa.eu/research-and-innovation/en/horizon-magazine/four-times-more-toxic-how-wildfire-smoke-ages-over-time">free radicals are generated</a> the longer smoke is exposed to UV light, so there’s a greater potential for health harm. A lot of that, again, comes down to dose.</p>
<figure class="align-center ">
<img alt="The city skyline disappears as the viewer looks farther into the haze, which is coming from wildfire smoke." src="https://images.theconversation.com/files/534619/original/file-20230628-17-fz8urj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534619/original/file-20230628-17-fz8urj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534619/original/file-20230628-17-fz8urj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534619/original/file-20230628-17-fz8urj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534619/original/file-20230628-17-fz8urj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534619/original/file-20230628-17-fz8urj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534619/original/file-20230628-17-fz8urj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Haze from wildfire smoke envelopes the Minneapolis skyline on June 14, 2023.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/CanadianWildfiresAirQuality/4dedf9a42ab04009a3f199e415fb66b1/photo">AP Photo/Abbie Parr</a></span>
</figcaption>
</figure>
<p>Chances are, if you’re a healthy individual, going for a bike ride or a hike in light haze won’t be a big deal, and your body will be able to recover. </p>
<p>If you’re doing that every day for a month in wildfire smoke, however, that raises more concerns. I’ve worked on studies with residents at Seeley Lake in Montana who were exposed to hazardous levels of PM2.5 from wildfire smoke for 49 days in 2017. We found a <a href="https://doi.org/10.3390/toxics8030053">decrease in lung function a year later</a>. No one was on oxygen, but there was a significant drop.</p>
<p>This is a relatively new area of research, and there’s still a lot we’re learning, especially with the increase in wildfire activity as the planet warms.</p>
<h2>What precautions can people take to reduce their risk from wildfire smoke?</h2>
<p>If there is smoke in the air, you want to decrease your exposure. </p>
<p>Can you completely avoid the smoke? Not unless you’re in a hermetically sealed home. The PM levels aren’t much different indoors and out unless you have a really good HVAC system, such as those with <a href="https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating">MERV 15 or better filters</a>. But going inside decreases your activity, so your breathing rate is slower and the amount of smoke you’re inhaling is likely lower.</p>
<figure class="align-center ">
<img alt="A satellite animation shows smoke moving from fires in Alberta across Canada and into New England." src="https://images.theconversation.com/files/527359/original/file-20230521-119053-ul9mif.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527359/original/file-20230521-119053-ul9mif.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527359/original/file-20230521-119053-ul9mif.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527359/original/file-20230521-119053-ul9mif.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527359/original/file-20230521-119053-ul9mif.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=511&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527359/original/file-20230521-119053-ul9mif.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=511&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527359/original/file-20230521-119053-ul9mif.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=511&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A satellite captures wildfire smoke on May 16, 2023.</span>
<span class="attribution"><a class="source" href="https://www.earthdata.nasa.gov/worldview/worldview-image-archive/canada-fires-16-may-2023">NASA EarthData</a></span>
</figcaption>
</figure>
<p>We also tend to advise people that if you’re in a susceptible group, such as those with asthma, create a safe space at home and in the office with a high-level stand-alone air filtration system to create a space with cleaner air.</p>
<p>Some <a href="https://doi.org/10.1038/s41370-020-00267-4">masks can help</a>. It doesn’t hurt to have a high-quality N95 mask. Just wearing a cloth mask won’t do much, though.</p>
<p>Most <a href="https://www.airnow.gov/">states have air quality monitors</a> that can give you a sense of how bad the air quality is, so check those sites and act accordingly.</p>
<p><em>This article was updated June 28, 2023, with smoke in Chicago, Minneapolis and Detroit and the latest map of smoke conditions.</em></p><img src="https://counter.theconversation.com/content/206057/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher T. Migliaccio has received funding from the NIH and HRSA for his work in wood smoke health effects.
. </span></em></p>Fires in Canada have sent smoke across several US states, leaving cities including New York, Chicago and Denver with some of the worst air quality in the world – even far from the flames.Christopher T. Migliaccio, Research Associate Professor in Toxicology, University of MontanaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1547202022-12-27T19:20:27Z2022-12-27T19:20:27ZHow to protect yourself against bushfire smoke this summer<figure><img src="https://images.theconversation.com/files/498606/original/file-20221202-20-fswf2q.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C1911%2C1279&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/Ihsi88KpQkE">Matt Palmer/Unsplash</a></span></figcaption></figure><p>It’s bushfire season. So you might be wondering about the best way to protect yourself from the health impacts of smoke.</p>
<p>Guidelines suggest wearing <a href="https://files-em.em.vic.gov.au/public/Smoke/EMK-01.19-Community-SAQH-Protocol.pdf">respirators</a>, <a href="https://www.health.nsw.gov.au/environment/air/Pages/bushfire-protection.aspx">avoiding</a> outdoor air and avoiding vigorous activity outdoors. Many people use the cheaper option of a surgical mask during bushfires. But there has never been a clinical trial to measure how well these interventions work. That’s why our group is <a href="https://kirby.unsw.edu.au/breathe">looking into it</a>.</p>
<p>In the meantime, here’s what you can do to reduce your exposure to bushfire smoke.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-summer-so-bushfires-and-covid-collide-3-ways-one-affects-the-other-169833">It's summer, so bushfires and COVID collide. 3 ways one affects the other</a>
</strong>
</em>
</p>
<hr>
<h2>Who’s at risk?</h2>
<p>Australia’s 2019/2020 summer bushfires resulted in <a href="https://www.theguardian.com/australia-news/2020/may/26/australias-summer-bushfire-smoke-killed-445-and-put-thousands-in-hospital-inquiry-hears">more than 400 estimated deaths</a> and thousands of hospitalisations from smoke exposure.</p>
<p>You don’t have to have a lung condition to suffer the <a href="https://theconversation.com/smoke-from-bushfires-poses-a-health-hazard-for-all-of-us-11493">ill-effects of bushfire smoke</a>. Breathing difficulties, eye irritation and heart attacks are among the <a href="https://theconversation.com/how-does-bushfire-smoke-affect-our-health-6-things-you-need-to-know-130126">well-documented</a> short-term impacts.</p>
<p>But people with asthma, <a href="https://theconversation.com/explainer-what-is-chronic-obstructive-pulmonary-disease-25539">emphysema</a>, chronic bronchitis and other lung conditions are particularly susceptible to smoke exposure, triggering asthma attacks and breathing difficulties.</p>
<p>This was the typical pattern we saw during our <a href="https://www.atsjournals.org/doi/10.1164/rccm.202012-4471LE?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed">own research</a>, conducted during the same bushfire season. We showed smoke exposure caused ill health in people with and without existing lung disease.</p>
<p>However, we found people under 65 had a higher risk of ill health after smoke exposure than older people. This may be because younger people tend to go outdoors more during bushfires.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-does-bushfire-smoke-affect-our-health-6-things-you-need-to-know-130126">How does bushfire smoke affect our health? 6 things you need to know</a>
</strong>
</em>
</p>
<hr>
<h2>1. Be prepared</h2>
<p>If you live in an area potentially affected by bushfire smoke, the first thing to do is to get an early alert about fires and smoke using one or more apps. Examples include, the <a href="https://www.rfs.nsw.gov.au/news-and-media/stay-up-to-date">Fires Near Me app</a> or the <a href="https://airrater.org">AirRater app</a> for air quality.</p>
<p>You can also use a <a href="https://iser.med.unsw.edu.au/sites/iser/files/_local_upload/Air%20quality%20self-assessment%20guide.pdf">visual method</a> to assess air quality. This involves identifying a landmark on the horizon about 5 kilometres away and noting if it becomes hazy. This would be the trigger for using a respirator or avoiding outdoor air.</p>
<h2>2. Stay inside if it’s safe</h2>
<p>Try to <a href="https://files-em.em.vic.gov.au/public/Smoke/EMK-01.19-Community-SAQH-Protocol.pdf">avoid exposure</a> to smoke, avoiding outside air and staying indoors if it is practical and safe to do so. Vigorous exercise outdoors can be dangerous as it results in greater smoke inhalation and risks to the heart and lungs.</p>
<p>Close all doors and windows, set air-conditioning to recirculate, and seal gaps under or around doors, windows and wall vents with towels, blankets or plastic. </p>
<p>Unfortunately, these instructions are the opposite of what to do if there is COVID at home, when you would want fresh air in the house. If that is the case, wear a mask indoors in common areas and social distance from the person with COVID.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/our-buildings-arent-made-to-keep-out-bushfire-smoke-heres-what-you-can-do-129367">Our buildings aren't made to keep out bushfire smoke. Here's what you can do</a>
</strong>
</em>
</p>
<hr>
<h2>3. Wear a respirator (not just a surgical mask)</h2>
<p>Most people who need to go outside during a bushfire can use some type of disposable respirator to filter the smokey air.</p>
<p>You will have seen people wearing these P2, P3 or N95 <a href="https://theconversation.com/how-to-get-the-most-out-of-your-n95-mask-or-other-respirator-177229">respirators</a> to protect themselves and others from SARS-CoV-2, the virus that causes COVID.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1496730465981640708"}"></div></p>
<p>These and <a href="https://www.addler.com.au/differences-p1-p2-p3-n95-respirators/">other types of disposable respirators</a> filter very fine particles and fit closely around the face. Choose one with a full band around the back of the head (rather than ear loops) as these provide a better fit.</p>
<p>Some disposable respirators have valves, which means they filter inhaled air but allow you to exhale more comfortably. This option may help people with asthma or lung disease to breathe more comfortably. If you have COVID, though, wearing a respirator with a valve does not reduce the risk of you infecting others, because the air you breathe out through the valve is unfiltered and contaminated.</p>
<p>Respirators will filter particles <a href="https://www.aiha.org/news/201022-osha-addresses-claims-that-n95s-do-not-protect-against-sars-cov-2">larger than 0.3 microns</a> (micrometres). However, they may not filter smaller particles contained in smoke, which is why avoiding outside air is still important.</p>
<p>People who live in bushfire-prone areas may want to consider a type of respirator they can clean and re-use when needed, known as <a href="https://healthcareworkersaustralia.com/elastomeric-mask/">an elastomeric respirator</a>. Their filters need to be changed at specified intervals.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Elastomeric face mask" src="https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499478/original/file-20221207-24-nezay8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An elastomeric mask, such as this one, can be re-used.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/reusable-halfface-elastomeric-respirator-air-purification-2196383995">Shutterstock</a></span>
</figcaption>
</figure>
<p>If you have trouble getting one of the mentioned respirators, you can use a disposable <a href="https://breathesafeair.com/mask-ratings/">KN95 respirator</a>. However, these have ear loops and do not fit well around the face, so air can leak through. </p>
<p>Surgical masks are not likely to protect you because they are so loose. But medical-grade ones provide good filtering. For this to be effective, wear one with a <a href="https://www.insider.com/ways-to-make-your-face-mask-more-effective-2021-2">mask brace or clip</a> to provide a better fit and to help prevent air leaking in from the sides.</p>
<h2>In a nutshell</h2>
<p>Be prepared by downloading an app to monitor bushfires and air quality near you, and stocking up on good quality respirators ahead of time if you can. You can re-use these if they are not visibly soiled or damaged.</p>
<p>Staying out of the smoke is also important, particularly if you have asthma, emphysema and other lung disease. Young people may be less aware of the health effects of smoke exposure, and even people without lung disease can experience ill health due to smoke.</p>
<hr>
<p><em>Do you have asthma, emphysema, chronic bronchitis or bronchiectasis? Do you live in an area in Australia affected by bushfires or bushfire smoke (including metropolitan areas)? You may be eligible to be part of <a href="https://kirby.unsw.edu.au/breathe">our study</a> into the best way to protect yourself from bushfire smoke.</em></p><img src="https://counter.theconversation.com/content/154720/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>C Raina MacIntyre has consulted for mask companies including Detmold and Ascend. She receives funding from the NHMRC and the MRFF currently.</span></em></p>Be prepared. Download an air quality app, stock up on respirators and stay inside if you can.C Raina MacIntyre, Professor of Global Biosecurity, NHMRC Principal Research Fellow, Head, Biosecurity Program, Kirby Institute, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1944002022-11-18T16:56:52Z2022-11-18T16:56:52ZWildfires often lead to dust storms – and they’re getting bigger<figure><img src="https://images.theconversation.com/files/495385/original/file-20221115-25-tww3fi.jpg?ixlib=rb-1.1.0&rect=26%2C0%2C5869%2C3924&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Firefighters battling to extinguish a wildfire.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/peloponnese-greece-05-august-2021-firefighters-2020076498">Ververidis Vasilis/Shutterstock</a></span></figcaption></figure><p>Wildfires affect large areas of the Earth’s surface and many of their effects occur at an alarming speed. The fires that consumed half of Australia’s <a href="https://www.nytimes.com/2020/02/04/world/australia/kangaroo-island-fire.html">Kangaroo Island</a> in 2019 left a trail of animal corpses in their wake. In 2021, wildfires burned over <a href="https://www.fire.ca.gov/stats-events/">2.5 million acres</a> of land in California. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/oNlG9Mqksiw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A wildfire tearing through Kangaroo Island in South Australia.</span></figcaption>
</figure>
<p>But wildfires have other harmful effects that are slower to materialise. Wildfires reduce vegetation cover and can damage soil to the extent that it retains <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007JG000474">less moisture</a>. As wind blows over the scarred landscape this can lead to the increased release of dust made from fine mineral grains (often less than 0.01 mm in diameter).</p>
<p>The wind lifts the dust emissions into the air where they can find themselves suspended in a global atmospheric process that transfers them around the world. Dust events can therefore affect areas far from the land close to a wildfire. </p>
<p>Scientists have long established that <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007JG000474">concentrations of atmospheric dust</a> increase following large wildfires. But the global extent of post-fire dust events has been an underresearched aspect of the study into the impact of wildfires. Now <a href="https://www.nature.com/articles/s41561-022-01046-6">researchers</a> from Peking and Princeton universities have identified that the duration and scale of post-fire atmospheric dust storms may be far greater than previously understood. </p>
<h2>Larger dust storms</h2>
<p>Using two decades of satellite observations, the researchers found that over 150,000 large wildfires had occurred worldwide between 2003 and 2020. At least 20 1km by 1km squares within an area of approximately 100km² had to include detectable fires for at least seven consecutive days for a fire event to be defined as a large wildfire. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large cloud of dust moving down a road against a clear blue sky." src="https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495375/original/file-20221115-16-h65e1a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Post-fire dust events are now lasting longer than they did before.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/large-dust-storm-blowing-96327557">Caleb Holder/Shutterstock</a></span>
</figcaption>
</figure>
<p>Over half of the large wildfires identified were followed by dust events. In these events, the concentration of atmospheric dust in the area surrounding the fire-affected region increased more than threefold on average. </p>
<p>Most of the dust storms continued for a few days after a fire. But in 10% of the events occurring in savannah and grassland areas, dust concentrations were still exceptionally high ten days later and occasionally more than three weeks after the fire. </p>
<p>Across the period of study, the researchers found that the duration of post-fire dust events increased significantly. A dust event that occurred in 2020 lasted 24 hours longer on average than it did in 2003.</p>
<h2>Should we be concerned?</h2>
<p>Atmospheric dust storms can have serious impacts on ecology and human health. </p>
<p>Dust emissions are rich in chemical nutrients including <a href="https://www.nature.com/articles/srep24736">phosphorus</a>, <a href="https://link.springer.com/article/10.1007/s10533-007-9142-y">nitrogen</a> and iron. Nutrients such as these are key elements of soil productivity. As the nutrient-rich top layer of soil is removed by wind, soil quality in the area affected by a fire is depleted. </p>
<p>But dust can also be transported vast distances via the global dust cycle. When deposited, nutrient-rich dust emissions can fertilise soils and oceans far from the affected area. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Orange coloured phytoplankton slicks in the ocean viewed from the top of a cliff." src="https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=804&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=804&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=804&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1010&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1010&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495379/original/file-20221115-11-b4nvjd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1010&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dust emissions contain the nutrients needed for phytoplankton to grow.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/view-top-cliff-fluted-cape-bruny-1260006310">Ludmilla Gatelier/Shutterstock</a></span>
</figcaption>
</figure>
<p><a href="https://www.nature.com/articles/s41586-021-03805-8">Research</a> has linked Australia’s wildfires in 2019–2020 to extensive phytoplankton blooms in the Southern Ocean. Dust emissions can provide phytoplankton with the nutrients needed for rapid growth, leading to the formation of blooms. Such blooms can harm local marine ecosystems by reducing the oxygen content of the water. </p>
<p>Smoke is an obvious <a href="https://ehp.niehs.nih.gov/doi/10.1289/ehp.1409277">health concern</a> associated with wildfires. Small, inhalable, coarse particles within smoke can cause respiratory damage. <a href="https://www.sciencedirect.com/science/article/pii/S0160412014002992?via%3Dihub">Research</a> links airborne particulate matter to over two million deaths worldwide each year. </p>
<p>Fine dust particles are even smaller (2.5 micrometres in diameter) and pose a similar threat. The researchers suggest that the risks posed by large wildfires to human health may extend well beyond the immediate plume of smoke and may continue long after the smoke has cleared.</p>
<h2>Does climate change have a role?</h2>
<p>It might be tempting to ascribe the observed increase in the duration of post-fire dust events to our warming climate. Climate change can make hot and dry weather conditions more common and create the conditions for dangerous wildfires.</p>
<p>Yet the researchers are cautious to adopt this explanation. They note only that enhanced dust emissions correlate with the number of previous fires at a given location. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small wildfire burning shrubs in a savannah landscape." src="https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495382/original/file-20221115-17-fau6o2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wildfires are an essential part of savannah ecosystems.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/wildfire-african-savanna-kenya-149319917">Belikova Oksana/Shutterstock</a></span>
</figcaption>
</figure>
<p>Fire is a natural part of many ecosystems and evidence for increasing wildfire frequency is <a href="https://royalsocietypublishing.org/doi/full/10.1098/rstb.2015.0345">complex</a>. Savannah ecosystems, which the study identifies as the landscape most prone to post-fire dust emissions, <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2745.2000.00435.x">owe their existence</a> to the presence of fire. Regular fires remove young trees and return the grassland community to its original state. </p>
<p>Determining whether a wildfire has been caused by direct human actions or climate change is also <a href="https://theconversation.com/climate-change-wildfire-risk-has-grown-nearly-everywhere-but-we-can-still-influence-where-and-how-fires-strike-185465">difficult</a>. Just as for climate change, human actions can influence wildfire activity. The use of fire to burn farming or logging residue, for example, increases the risk of wildfire.</p>
<p>Scientists increasingly understand that wildfires are a feature of the natural world. But their impacts can be dangerous and extend well beyond the margins of the fire itself.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 10,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/194400/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Telfer does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Atmospheric dust storms often follow wildfires and have serious impacts on human health and ecology.Matt Telfer, Associate Professor of Physical Geography, University of PlymouthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1916432022-10-20T19:09:46Z2022-10-20T19:09:46ZWildfire smoke may warm the Earth for longer than we thought<figure><img src="https://images.theconversation.com/files/490388/original/file-20221018-8304-u2jqmk.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C6500%2C4310&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Thick smoke fills the air and nearly blocks out the sun, east of Kamloops, B.C., on Aug. 14, 2021. </span> <span class="attribution"><span class="source">THE CANADIAN PRESS/Darryl Dyck</span></span></figcaption></figure><p>Wildfires are a major source of air pollution. They are also <a href="https://www.nrcan.gc.ca/our-natural-resources/forests/wildland-fires-insects-disturbances/climate-change-fire/13155">predicted to worsen</a> as climate change progresses. </p>
<p>Within the smoke particles produced by these fires is a wide range of organic chemical compounds known as “<a href="https://pubs.acs.org/doi/10.1021/cr5006167">brown carbon</a>.” Brown carbon absorbs sunlight, and in doing so, <a href="https://doi.org/10.5194/acp-13-8607-2013">contributes to global warming</a>.</p>
<p>Over time, the brown carbon is <a href="https://doi.org/10.1002/2015GL063897">bleached by chemical reactions with oxidants</a> in the atmosphere (such as ozone) and becomes white. This means that it stops absorbing light and stops warming Earth. </p>
<p>This bleaching process is heavily dependent on atmospheric conditions, which vary across regions. The longer it takes for brown carbon to become white, the greater an impact it can have on the environment.</p>
<p>As <a href="https://bertram.chem.ubc.ca/">atmospheric chemists</a> living in a region <a href="https://www.cbc.ca/news/canada/british-columbia/bc-wildfires-monday-september-12-2022-1.6580028">frequently polluted by wildfire smoke</a>, we wanted to know more about these effects. We worked together with atmospheric chemists at the <a href="https://www.abbattgroup.ca/">University of Toronto</a> and <a href="https://schnitzlerlab.okstate.edu/">Oklahoma State University</a>, along with atmospheric modellers at the <a href="https://www.healdgroupmit.com/">Massachusetts Institute of Technology</a>, to <a href="https://doi.org/10.1073/pnas.2205610119">find out just how long this bleaching process takes and the atmospheric impacts</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4oJ0j1OZSTU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Guardian News takes a look at why wildfires are getting worse.</span></figcaption>
</figure>
<h2>Aerosols and climate</h2>
<p>Aerosols are microscopic liquid and solid particles suspended in the atmosphere. They’re smaller than the width of a human hair, but are still made up of many molecules. </p>
<p>Aerosol particles are everywhere and have a large effect <a href="https://doi.org/10.1021/acs.est.7b04417">on both health</a> and <a href="https://doi.org/10.1126/science.255.5043.423">the climate</a>. When aerosol particles interact with light, a portion of the light is absorbed but the rest reflects and scatters off of the particles. </p>
<p>For most types of aerosol particles, the amount being absorbed is negligible. That means <a href="https://doi.org/10.1029/2019RG000660">a lot of the light reflects back to space</a>. Through this mechanism, some of the pollution we create <a href="https://climate.nasa.gov/news/2612/can-poor-air-quality-mask-global-warmings-effects/">actually masks the full impact of greenhouse gases</a>. </p>
<p>Some aerosol particles, however, are coloured, which means <a href="https://doi.org/10.1038/s43017-022-00296-7">they are absorbing some light</a>. Any light from the sun that is absorbed instead of getting reflected back into space is converted into heat and warms the planet.</p>
<p>Aerosol particles from smoke contain brown carbon. The various molecules that make up brown carbon are similar to some organic dyes, overall giving it a characteristic brown colour. However, when ozone in the atmosphere reacts with brown carbon, it can transform it into new colourless molecules that do not warm the earth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="overhead shot of a fire's progress through a forest toward a highway" src="https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490390/original/file-20221018-26-lw1136.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wildfires are a major source of air pollution, including brown carbon, which can contribute to global warming.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Significantly slower reaction</h2>
<p>It was previously assumed that reactions between brown carbon and ozone were relatively fast. Within one day of being emitted from a fire, brown carbon would mostly stop absorbing solar radiation. But now, through a combination of laboratory experiments and atmospheric simulations, it is clear that the reaction between brown carbon and ozone can be significantly slower.</p>
<p>Experiments on pine wood smoke showed that <a href="https://doi.org/10.1073/pnas.1219548110">brown carbon quickly lost its colour when exposed to ozone in a warm, humid environment</a>. Conversely, when the temperature and humidity were decreased, the brown carbon remained.</p>
<p>This is because temperature and humidity change the viscosity of aerosol particles. Humid conditions lead to a lot of water getting absorbed into the particles, and as a result they become very fluid. But if that water is removed and the aerosols get cold, they become very viscous, like molasses — <a href="https://doi.org/10.1038/ncomms15002">or even glass in extreme conditions</a>.</p>
<p>For an oxidant like ozone to bleach brown carbon, ozone needs to penetrate and mix within the smoke particles. When smoke particles become viscous, the oxidants take an extremely long time to mix — over a year in some cases. </p>
<p>At altitudes less than 1 km in the atmosphere, conditions are relatively warm and humid so smoke particles are often not very viscous and brown carbon bleaches quickly. But at higher altitudes the air is drier and colder. When smoke particles get up to these heights, they can become highly viscous and the bleaching process can be so slow that it practically does not happen.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="people play golf in a smoky atmosphere" src="https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490389/original/file-20221018-8895-9cipur.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Thick smoke from wildfires blankets the area as people play golf.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Darryl Dyck</span></span>
</figcaption>
</figure>
<h2>Atmospheric modelling</h2>
<p>The result is significantly different when we put this new, longer-lasting brown carbon into an atmospheric model that simulates the transport of aerosols around the planet and how they interact with solar radiation. The new results show
a warming effect on the climate from brown carbon <a href="https://doi.org/10.1029/2021JD034984">that is twice that of the previous estimate</a>. </p>
<p>This represents another important piece of the climate puzzle.</p>
<p>The Stockholm Resilience Centre’s <a href="https://www.stockholmresilience.org/research/planetary-boundaries.html">Planetary Boundaries framework</a> identifies the processes that regulate the stability and resilience of the Earth system. Aerosols are classified as one of the nine key ways that humans change the environment, but the total risk they pose remains unquantified within the Planetary Boundaries framework. </p>
<p>Research on aerosols can bring us closer to understanding their total effect on the environment, which will make us more prepared and better equipped to deal with the future of our planet.</p><img src="https://counter.theconversation.com/content/191643/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Allan Bertram receives funding from the Natural Sciences and Engineering Research Council of Canada. </span></em></p><p class="fine-print"><em><span>Nealan Gerrebos does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Brown carbon refers to a range of pollutants found in smoke from wildfires. They can contribute to global warming before they undergo a process that alters their chemical properties.Nealan Gerrebos, PhD Student, Chemistry, University of British ColumbiaAllan Bertram, Professor, Chemistry, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1874222022-08-29T12:39:49Z2022-08-29T12:39:49ZExtreme heat and air pollution can be deadly, with the health risk together worse than either alone<figure><img src="https://images.theconversation.com/files/481425/original/file-20220828-7442-4j6f2d.jpg?ixlib=rb-1.1.0&rect=37%2C37%2C3551%2C2355&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bad air pollution and extreme heat each raise health risks, but they're worse combined.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/los-angeles-resident-carmen-green-jumps-rope-at-a-closed-news-photo/1228565250">Brian van der Brug/Los Angeles Times via Getty Images</a></span></figcaption></figure><p>Heat waves and air pollution from wildfire smoke and other sources are <a href="https://doi.org/10.1001/jama.2017.17923">each problematic</a> for <a href="https://doi.org/10.1016/S0140-6736(21)01208-3">human health</a>, particularly for vulnerable populations such as older adults. But what happens when they hit at the same time?</p>
<p>We examined over 1.5 million deaths from 2014 to 2020 registered in California – a state prone to summer heat waves and air pollution from wildfires – to find out.</p>
<h2>Deaths spike when both risks are high</h2>
<p>The number of deaths rose both on hot days and on days with high levels of fine particulate air pollution, <a href="https://www.health.ny.gov/environmental/indoors/air/pmq_a.htm">known as PM2.5</a>. But on days when an area was hit with a double whammy of both high heat and high air pollution, the effects were much higher than for each condition alone.</p>
<p>The risk of death on those extra-hot and polluted days was about <a href="https://doi.org/10.1164/rccm.202204-0657OC">three times greater</a> than the effect of either high heat or high air pollution alone.</p>
<p>The more extreme the temperatures and pollution, the <a href="https://doi.org/10.1164/rccm.202204-0657OC">higher the risk</a>. During the top 10% of hottest and most polluted days, the risk of death increased by 4% compared to days without extremes. During the top 1%, it increased by 21%; and among older adults over age 75, the risk of death increased by more than a third on those days.</p>
<p><iframe id="2f0eY" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/2f0eY/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Why risks are higher when both hit at once</h2>
<p>There are several ways the combined exposure to extreme heat and particulate air pollution can harm human health.</p>
<p>Oxidative stress is the most common biological pathway linked with particulate air pollution and heat exposure. <a href="https://doi.org/10.1038/s41573-021-00233-1">Oxidative stress</a> is an imbalance between production of highly reactive molecules known as reactive oxygen species, or ROS, and the body’s ability to remove them. It’s been linked with <a href="https://link.springer.com/chapter/10.1007/978-981-32-9366-3_5">lung diseases</a>, among other illnesses. </p>
<p>Antioxidants help clean up these molecules, but particulate air pollution and heat disrupt this balance through excessive metabolic ROS production and lowered antioxidant activity.</p>
<p>Our research also showed that the effects of particulate air pollution and heat extremes were <a href="https://doi.org/10.1164/rccm.202204-0657OC">larger when high nighttime temperature and pollution occurred together</a>. High nighttime temperatures can <a href="https://doi.org/10.1016/S2542-5196(22)00139-5">interfere with normal sleep</a> and potentially contribute to chronic health conditions such as <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/215006">heart disease</a> and <a href="https://www.pnas.org/doi/full/10.1073/pnas.1216951110">obesity</a>, and disrupt how the body regulates temperature.</p>
<p>Older adults may be more susceptible to effects of extreme heat and air pollution exposure, in part because this stress comes on top of age-related chronic health conditions like heart disease, high blood pressure, diabetes or chronic lung disease. <a href="https://www.ncbi.nlm.nih.gov/books/NBK507838/">Impaired body temperature regulation</a> in response to heat can also occur with aging. And older adults may be less mobile and therefore less able to get to cooling centers or to medical care and be less able to afford air conditioning. </p>
<h2>A future of high temperatures and air pollution</h2>
<p>This isn’t just a California problem. Climate change will increase exposure to high heat and air pollution in many parts of the country. </p>
<p>Yearly average temperatures in the U.S. are already more than 1.8 degrees Fahrenheit (1 degree Celsius) warmer than at the beginning of the 1900s. By the end of this century, global temperatures are on pace to be <a href="https://www.unep.org/resources/emissions-gap-report-2021">nearly 5 F (2.7 C) warmer</a>. Dangerous extreme heat waves, currently rare, will <a href="https://science2017.globalchange.gov/chapter/6/">become more common</a>. </p>
<p>Changing climate is also <a href="http://doi.org/10.1016/j.amepre.2008.08.025">affecting levels</a> of outdoor fine particulate pollution – for example, through weather changes such as air stagnation events, wind and dust storms, and drier and warmer conditions that <a href="https://nca2018.globalchange.gov/chapter/13/">contribute to increasingly frequent and intense wildfires</a>.</p>
<h2>What to do to stay safe</h2>
<p>Further research is needed to better understand these effects, such as the full impact of wildfire smoke exposure. However, enough is known that people should take measures to reduce their risk of harm during periods of extreme heat or air pollution.</p>
<p>That means staying <a href="https://www.cdc.gov/disasters/extremeheat/heattips.html">well hydrated and keeping cool</a>. Shopping malls and other air-conditioned public spaces can provide a refuge from heat. Home air conditioning, especially during nighttime, can reduce mortality. A portable air filter in the bedroom can <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ina.12753">markedly reduce particle pollution levels</a>.</p>
<p>People with <a href="https://www.cdc.gov/disasters/extremeheat/warning.html">symptoms of heat stress</a>, such as headache, nausea, dizziness or confusion, especially the elderly, should seek medical care. </p>
<p>Many county and state health departments already provide alerts about extreme heat and extreme air pollution. Developing a special category of alert during co-occurring extremes may be beneficial to public health.</p>
<p>Governments also need to take steps now to avoid the worst future climate change scenarios. Some best practices for cities include creating cooling shade cover and green space that will also reduce particle pollution.</p><img src="https://counter.theconversation.com/content/187422/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erika Garcia receives support from Southern California Environmental Health Sciences Center, National Institute of Environmental Health Sciences grant P30ES007048, and the University of Southern California Office of Research Strategic Development of Research Award.</span></em></p><p class="fine-print"><em><span>Rob Scot McConnell receives funding from the National Institute of Environmental Health Sciences</span></em></p><p class="fine-print"><em><span>Md Mostafijur Rahman does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The worst effects are during high nighttime temperatures, something happening more often with climate change. Wildfire smoke adds to the risk.Erika Garcia, Assistant Professor of Population and Public Health Sciences, University of Southern CaliforniaMd Mostafijur Rahman, Postdoctoral Scholar and Research Associate in Environmental Health, University of Southern CaliforniaRob Scot McConnell, Professor of Population and Public Health Sciences, University of Southern CaliforniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1864532022-07-06T12:18:51Z2022-07-06T12:18:51ZAlaska on fire: Thousands of lightning strikes and a warming climate put Alaska on pace for another historic fire season<figure><img src="https://images.theconversation.com/files/472711/original/file-20220706-19-hjye2.jpg?ixlib=rb-1.1.0&rect=0%2C108%2C4031%2C2909&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A large tundra fire burned near St. Mary's, Alaska, on June 13, 2022.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/blmalaskafireservice/52157039455/in/album-72177720299701992/">BLM Alaska Fire Service/Incident Management Team/John Kern</a></span></figcaption></figure><p><em>Alaska is on pace for another historic wildfire year, with its fastest start to the fire season on record. By mid-June 2022, <a href="https://alaskabeacon.com/briefs/climate-change-cited-as-factor-in-early-alaska-wildfire-milestone/">over 1 million acres</a> had burned. By early July, that number was well <a href="https://akfireinfo.com/2022/07/03/alaska-surpasses-2-million-acres-burned">over 2 million</a> acres, more than twice the size of a <a href="https://fire.ak.blm.gov/content/aicc/Statistics%20Directory/Alaska%20Fire%20History%20Chart%20with%20Data.xls">typical Alaska fire season</a>.</em></p>
<p><em>We asked Rick Thoman, <a href="https://news.uaf.edu/expertsguide/rick-thoman/">a climate specialist</a> at the International Arctic Research Center in Fairbanks, why Alaska is seeing so many large, intense fires this year and how the region’s fire season is changing.</em></p>
<h2>Why is Alaska seeing so many fires this year?</h2>
<p>There isn’t one simple answer.</p>
<p>Early in the season, southwest Alaska was one of the few areas in the state with <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/ak/snow/">below normal snowpack</a>. Then we had a warm spring, and southwest Alaska dried out. An outbreak of thunderstorms there in late May and early June provided the spark. </p>
<p>Global warming has also increased the amount of fuels – the plants and trees that are available to burn. More fuel means <a href="https://www.doi.gov/wildlandfire/fuels">more intense fires</a>.</p>
<p>So, the weather factors – the warm spring, low snowpack and unusual thunderstorm activity – combined with <a href="https://www.ncei.noaa.gov/cag/statewide/time-series/50/tavg/12/12/1895-2022?base_prd=true&begbaseyear=1901&endbaseyear=2000">multidecade warming</a> that has allowed vegetation to grow in southwest Alaska, together fuel an active fire season. </p>
<figure class="align-center ">
<img alt="Chart shows 2022 starting faster than any of the other large fire years on record and on pace with the 2015 fire season." src="https://images.theconversation.com/files/473047/original/file-20220707-26-cube2k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/473047/original/file-20220707-26-cube2k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/473047/original/file-20220707-26-cube2k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/473047/original/file-20220707-26-cube2k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/473047/original/file-20220707-26-cube2k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/473047/original/file-20220707-26-cube2k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/473047/original/file-20220707-26-cube2k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">2022 is among Alaska’s busiest fire seasons in over 30 years of records.</span>
<span class="attribution"><a class="source" href="https://akfireinfo.com/">AICC</a></span>
</figcaption>
</figure>
<p>In Alaska’s interior, much of the area has been <a href="https://droughtmonitor.unl.edu/data/png/20220628/20220628_ak_trd.png">abnormally dry</a> since late April. So, with the lightning storms, it’s no surprise that we’re now seeing many fires in the region. The interior had <a href="https://twitter.com/AlaskaWx/status/1544000284820590594">about 18,000 strikes</a> over two days in early July. </p>
<h2>Are lightning storms like this becoming more frequent?</h2>
<p>That’s the million-dollar question.</p>
<p>It’s actually a two-part question: Are thunderstorms occurring more often now in places that used to rarely get them? I think the answer is unequivocally “yes.” Is the total number of strikes increasing? We don’t know, because the networks tracking lightning strikes today are far more sensitive than in the past.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/472624/original/file-20220705-5022-ahqp5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472624/original/file-20220705-5022-ahqp5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=525&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472624/original/file-20220705-5022-ahqp5v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=525&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472624/original/file-20220705-5022-ahqp5v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=525&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472624/original/file-20220705-5022-ahqp5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=660&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472624/original/file-20220705-5022-ahqp5v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=660&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472624/original/file-20220705-5022-ahqp5v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=660&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Lightning strikes in Alaska July 2-4, 2022.</span>
<span class="attribution"><a class="source" href="https://twitter.com/AlaskaWx/status/1544000284820590594">AICC</a></span>
</figcaption>
</figure>
<p>Thunderstorms in Alaska are different from in most of the lower 48 in the sense that they tend to not be associated with weather fronts. They’re what meteorologists call <a href="https://doi.org/10.1175/BAMS-D-16-0064.1">air mass or pulse thunderstorms</a>. They’re driven by two factors: the available moisture in the lower atmosphere and the temperature difference between the lower and middle atmospheres.</p>
<p>In a warming world, <a href="https://theconversation.com/the-water-cycle-is-intensifying-as-the-climate-warms-ipcc-report-warns-that-means-more-intense-storms-and-flooding-165590">air can hold more moisture</a>, so you can get intense storms. In interior Alaska, we’re getting thunderstorms more frequently. For example, the number of days with thunderstorms <a href="https://uaf-accap.org/air-temperature/other-climate-weather-graphics/">recorded at the Fairbanks Airport</a> show a clear increase. Indigenous elders also agree that they’re seeing thunderstorms more often.</p>
<h2>You mentioned hotter fires. How are wildfires changing?</h2>
<p>Wildfire is part of the natural ecosystem in the Boreal north, but the fires we’re getting now are not the same as the fires that were burning 150 years ago.</p>
<p>More fuel, more lightning strikes, higher temperatures, lower humidity – they combine to fuel fires that burn hotter and burn deeper into the ground, so rather than just scorching the trees and burning the undergrowth, they’re consuming everything, and you’re left with this moonscape of ash.</p>
<p><a href="https://www.pnas.org/doi/10.1073/pnas.2024872118">Spruce trees</a> that <a href="https://beta.nsf.gov/news/black-spruce-trees-struggle-regenerate-amid-more-frequent-arctic-fires">rely on fire</a> to burst open their cones can’t reproduce when the fire turns those cones to ash. People who have been out in the field fighting fire for decades say they’re amazed at the amount of destruction they see now. </p>
<figure class="align-center ">
<img alt="Firefighters in tall grass silhouetted by flames in the trees beyond." src="https://images.theconversation.com/files/472686/original/file-20220706-17-z1n7gv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472686/original/file-20220706-17-z1n7gv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=779&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472686/original/file-20220706-17-z1n7gv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=779&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472686/original/file-20220706-17-z1n7gv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=779&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472686/original/file-20220706-17-z1n7gv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=979&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472686/original/file-20220706-17-z1n7gv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=979&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472686/original/file-20220706-17-z1n7gv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=979&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fire crews walk through tall vegetation as they conduct defensive burning against a large complex of fires near Lime Village, Alaska. The group of fires totaled more than 780,000 acres on July 5, 2022.</span>
<span class="attribution"><a class="source" href="https://akfireinfo.com/2022/07/05/high-humidity-and-defensive-burning-reducing-lime-complex-fire-spread/">Bryan Quimby/Alaska Incident Management Team</a></span>
</figcaption>
</figure>
<p>So while fire has been natural here for tens of thousands of years, the fire situation has changed. The frequency of million-acre fires in Alaska <a href="https://uaf-iarc.org/alaskas-changing-environment/">has doubled since before 1990</a>.</p>
<h2>What impact are these fires having on the population?</h2>
<p>The most common impact on humans is smoke.</p>
<p>Most wildfires in Alaska aren’t burning through heavily populated areas, though that does happen. When you’re burning 2 million acres, you’re burning a lot of trees, and so you’re putting a lot of smoke into the air, and it travels long distances.</p>
<p>In early July, we saw explosive <a href="https://alaskabeacon.com/briefs/alaska-wildfires-and-their-smoke-force-closures-cancelations-and-exacuations/">wildfire activity north of Lake Iliamna</a> in southwest Alaska. The winds were blowing from the southeast then, and dense smoke was transported hundreds of miles. In Nome, 400 miles away, the air quality index at the hospital <a href="https://twitter.com/AlaskaWx/status/1542899411080007681">exceeded 600 parts per million</a> for PM2.5, fine particulate matter that <a href="https://ww2.arb.ca.gov/resources/inhalable-particulate-matter-and-health">can trigger asthma</a> and harm the lungs. Anything <a href="https://www.airnow.gov/aqi/aqi-basics/">over 150 ppm is unhealthy</a>, and over 400 ppm is considered hazardous.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/472631/original/file-20220705-23-jymkxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472631/original/file-20220705-23-jymkxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472631/original/file-20220705-23-jymkxn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472631/original/file-20220705-23-jymkxn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472631/original/file-20220705-23-jymkxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472631/original/file-20220705-23-jymkxn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472631/original/file-20220705-23-jymkxn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fires burning on June 10, 2022, seen from a satellite.</span>
<span class="attribution"><span class="source">NASA Earth Observatory</span></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/472632/original/file-20220705-13-vslisk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472632/original/file-20220705-13-vslisk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472632/original/file-20220705-13-vslisk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472632/original/file-20220705-13-vslisk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472632/original/file-20220705-13-vslisk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472632/original/file-20220705-13-vslisk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472632/original/file-20220705-13-vslisk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A close-up view shows where people were evacuated near one of the region’s largest tundra fires on record.</span>
<span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/149973/alaska-ablaze">NASA Earth Observatory</a></span>
</figcaption>
</figure>
<p>There are other risks. When fires threaten rural Alaska communities, <a href="https://www.alaskapublic.org/2022/06/10/vulnerable-residents-flown-out-of-st-marys-and-pitkas-point-as-major-tundra-fire-closes-in/">as one did near St. Mary’s</a> in June 2022, evacuating can mean flying people out.</p>
<p>Worsening fire seasons also put pressure on firefighting resources everywhere. Firefighting is expensive, and Alaska counts on fire crews, planes and equipment from the lower 48 states and other countries. In the past, when Alaska had a big fire season, crews would come up from the lower 48 because their fire season was typically much later. Now, wildfire season there is all year, and there are fewer movable resources available.</p><img src="https://counter.theconversation.com/content/186453/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rick Thoman does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Fires today are hotter and more destructive, thanks in part to a warming climate.Rick Thoman, Alaska Climate Specialist, University of Alaska FairbanksLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1842062022-06-03T12:17:15Z2022-06-03T12:17:15ZWhat makes smoky, charred barbecue taste so good? The chemistry of cooking over an open flame<figure><img src="https://images.theconversation.com/files/466829/original/file-20220602-15-5dw0hs.jpg?ixlib=rb-1.1.0&rect=156%2C260%2C1637%2C1085&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cooking food over an open flame produces unique flavors thanks to some interesting chemistry. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/man-preparing-food-on-barbecue-grill-royalty-free-image/717232191?adppopup=true">Lars Szatmari / EyeEm via Getty Images</a></span></figcaption></figure><p>The mere thought of barbecue’s smoky scents and intoxicating flavors is enough to get most mouths watering. Summer is here, and that means it is barbecue season for many people in the U.S.</p>
<p>I am a <a href="https://chemistry.richmond.edu/faculty/knolin/">chemist who studies compounds found in nature</a>, and I am also a lover of food – including barbecue. Cooking on a grill may seem simple, but there is a lot of chemistry that sets barbecue apart from other cooking methods and results in such a delicious experience.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Burning charcoal with a reddish glow at the center." src="https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=423&fit=crop&dpr=1 600w, https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=423&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=423&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=532&fit=crop&dpr=1 754w, https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=532&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/466834/original/file-20220602-20-nek9jj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=532&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cooking over an open flame – whether from gas, wood or charcoal – allows you to use both radiant and conductive heat to cook food.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Charbon_de_bois_rouge.jpg#/media/File:Charbon_de_bois_rouge.jpg">Romary/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Cooking with fire</h2>
<p>First, it is important to define barbecue because the term can mean different things in different cultures or geographic locations. At its most basic, barbecue is the cooking of food over an open flame. What sets barbecue apart from other cooking methods is how heat reaches the food.</p>
<p>On a barbecue, the hot grill grates heat the food via direct contact through a process known as <a href="https://www.physicsclassroom.com/class/thermalP/Lesson-1/Methods-of-Heat-Transfer">conduction</a>. The food also warms and cooks by absorbing <a href="https://www.physicsclassroom.com/class/thermalP/Lesson-1/Methods-of-Heat-Transfer">radiation</a> directly from the flames below. The mix of heating methods allows you to sear the parts of the food touching the grill while simultaneously cooking the parts that aren’t touching the griddle – like the sides and top – through radiating heat. The resulting range of temperatures creates a complex mixture of flavors and aromas. When cooking on a stovetop, there is much less radiation and most of the cooking is done where the food is in direct contact with the pan.</p>
<p>When barbecuing, you can either put the food directly above the flames – what is called <a href="https://barbecuebible.com/recipe/direct-vs-indirect-grilling/">direct heat</a> – or farther away on indirect heat. The direct cooking method subjects the food to very high temperatures, as the grilling surface can be <a href="https://barbecuebible.com/recipe/direct-vs-indirect-grilling/">anywhere from 500 to 700 degrees Fahrenheit</a> (260 to 371 Celsius). The indirect cooking method places the heat source to the side of the food or far below, exposing the food to temperatures around 200 to 300 F (93 to 149 C). </p>
<p>Cooking is the process of using <a href="https://www.scienceofcooking.com/enzymatic-non-enzymatic-browning-of-foods.html">high temperatures to drive chemical reactions</a> that change food at a molecular level. When you cook meat at higher temperatures – like over direct heat on a barbecue – the first thing to happen is that water near the meat’s surface boils off. Once the surface is dry, the heat causes the proteins and sugars on the outside of the meat to undergo a reaction called the <a href="https://cen.acs.org/articles/90/i40/Maillard-Reaction-Turns-100.html">Maillard Reaction</a>. This reaction produces a complex mixture of molecules that make food taste more savory or “meaty” and adds depth to scents and flavors. The reaction and the flavors it produces are influenced by many variables, including temperature and acidity as well as the ingredients within any sauces, rubs or marinades.</p>
<p>A similar process occurs with vegetables. Barbecuing allows the water to evaporate or drip down without getting trapped by a pan. This keeps the vegetables from becoming soggy and promotes <a href="https://doi.org/10.1016/0308-8146(94)90188-0">caramelization reactions</a>. These reactions turn carbohydrates and sugars into smaller compounds like <a href="https://doi.org/10.1021/jf60171a044">maltol</a> – which has a toasty flavor – and furan – which tastes nutty, meaty and caramel-like.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A piece of corn and a large mushroom showing blackened spots." src="https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/466833/original/file-20220602-14-1352n5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">It’s much easier to control the level of charring on food when cooking on a barbecue.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Barbecue_corn_and_mushroom_(7872340508).jpg#/media/File:Barbecue_corn_and_mushroom_(7872340508).jpg">Lablascovegmenu/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Char and crisp</h2>
<p>Another hallmark of barbecued food is the unique char it develops. When foods are exposed to heat for prolonged periods of time, non-carbon atoms in the food break down, leaving behind the crispy, black carbon. This is the process of <a href="https://www.masterclass.com/articles/charred-food-explained#quiz-0">burning or charring</a>. </p>
<p>Almost no one likes a completely burnt piece of meat, but little splashes of crispy char flavor can add such depth to foods. Cooking over the direct heat of a barbecue allows you to add just the amount of char to match your taste.</p>
<p>Unfortunately for those who like a little extra crisp, some of the chemicals in charred meat – molecules called heterocyclic amines and polycyclic aromatic hydrocarbons – are known <a href="https://doi.org/10.1080%2F01635580802710741">carcinogens</a>. Though the dangers are far lower than smoking cigarettes, for example, limiting the amount of charring on meats <a href="https://blog.dana-farber.org/insight/2019/09/does-burnt-food-cause-cancer/">can help reduce the risk of developing cancer</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Sausages over a smoky grill." src="https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=369&fit=crop&dpr=1 600w, https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=369&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=369&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=463&fit=crop&dpr=1 754w, https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=463&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/466832/original/file-20220602-9439-upcqjj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=463&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Smoke gives barbecued foods much of their unique flavor.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Harry_Knight_2017-05-28_(Unsplash).jpg#/media/File:Harry_Knight_2017-05-28_(Unsplash).jpg">Harry Knight/Unsplash Photos</a></span>
</figcaption>
</figure>
<h2>Smoky flavors</h2>
<p>The final quintessential barbecue flavor is smokiness. Cooking over wood or charcoal involves a lot of smoke. Even on a gas grill, melting fats will drip onto the heat source and produce smoke. As smoke swirls around the barbecue, the food will absorb its flavors.</p>
<p>Smoke is made up of gases, water vapor and small solid particles from the fuel. Burning wood breaks down molecules called <a href="https://www.smokedbbqsource.com/science-of-smoke/">lignans</a>, and these turn into <a href="https://doi.org/10.1002%2Ffsn3.9">smaller organic molecules</a> – including syringol and guaiacol – that are mainly responsible for the quintessential smoky flavor.</p>
<p>When smoke comes in contact with food, the components of the smoke can <a href="https://www.smokedbbqsource.com/science-of-smoke/">get absorbed</a>. Food is particularly good at taking on smoky flavors because it contains both fats and water. Each binds to different types of molecules. In chemistry terms, fats are non-polar – meaning they have a weak electric charge – and easily grab other non-polar molecules. Water is polar – meaning it has areas of positive charge and an area of negative charge similar to a magnet – and is good at binding to other polar molecules. Some foods are better at absorbing smoky flavors than others, depending on their composition. One way to use chemistry to make food more smoky is to periodically spray it with water during the barbecuing process.</p>
<p>Smoke can contain hundreds of possible <a href="https://www.epa.gov/burnwise/wood-smoke-and-your-health">carcinogens</a> depending on what you are burning. Only a <a href="https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet">small amount of research</a> has been done on whether grilled foods absorb enough smoke to pose a significant risk to health. But researchers know that <a href="https://www.lung.org/clean-air/at-home/indoor-air-pollutants/residential-wood-burning">inhaling smoke</a> is strongly correlated with cancer.</p>
<p>While the idea of barbecuing your favorite dish may evoke the feeling of simple pleasures, the science behind it is quite complex. The next time you enjoy the smoky goodness of food from a grill, you will hopefully appreciate the diverse nature of the compounds and reactions that helped produce it.</p><img src="https://counter.theconversation.com/content/184206/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kristine Nolin does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Barbecued food has unique and often delicious flavors. A food chemist explains how the process of grilling over an open flame can produce flavors unattainable through other cooking methods.Kristine Nolin, Associate Professor of Chemistry, University of RichmondLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1734082021-12-14T13:29:39Z2021-12-14T13:29:39ZSmoke, heat and stress: A snapshot from Southern California of life in an altered climate<figure><img src="https://images.theconversation.com/files/437008/original/file-20211210-87869-zjhnwe.jpg?ixlib=rb-1.1.0&rect=7%2C0%2C4678%2C3119&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A lone jogger runs during a heat wave in the Kenneth Hahn State Recreation Area in Los Angeles on June 17, 2021. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/person-runs-in-the-heat-in-the-kenneth-hahn-state-news-photo/1233538024">Xinhua via Getty Images</a></span></figcaption></figure><p>From record-breaking heat waves to massive wildfires, floods and long-running drought, the impacts of climate change across the U.S. have been impossible to ignore in 2021. While conditions vary from one region to another, it is clear that no part of the nation will be unaffected.</p>
<p>I work in Southern California, a region long famous for its temperate climate. For the past two years, my colleagues and I at the <a href="https://cesr.usc.edu/">USC Dornsife Center for Economic and Social Research</a> have been surveying a representative internet panel of 1,800 Los Angeles County residents to better understand how social and environmental factors such as climate change affect people’s well-being.</p>
<p>For areas of the U.S. that have yet to feel the full force of rising temperatures, the results of our latest <a href="https://cesr.usc.edu/labarometer/overview">USC Dornsife-Union Bank LABarometer</a> <a href="https://cesr.usc.edu/sites/default/files/LABSustainability_wave2_final.pdf">survey</a> show what kinds of challenges they can expect. In Los Angeles the climate crisis is already reducing the quality of residents’ lives. And our findings clearly show that its impacts are falling disproportionately on residents who are young, poor, Black and Hispanic. </p>
<h2>Growing numbers are staying indoors</h2>
<p>The COVID-19 pandemic wasn’t the only threat to public health in 2021. Wildfires burned more than <a href="https://www.nifc.gov/fire-information/nfn">6.8 million acres</a> across the U.S. after consuming 10.1 million acres in 2020. And our data shows that many L.A. residents stay home when wildfires threaten air quality in their neighborhoods. </p>
<p>According to our survey, 50% of Angelenos avoided going outdoors at some point between July 2020 and July 2021 because of air quality concerns from a nearby wildfire, up from 30% in the previous year. We expect this number will continue to grow as wildfires increase in frequency and size. A recent <a href="https://ceo.lacounty.gov/wp-content/uploads/2021/10/LA-County-Climate-Vulnerability-Assessment-1.pdf">climate vulnerability assessment</a> predicts that by 2050 there could be a 40% increase in area burned by wildfires in Los Angeles.</p>
<p>Large-scale wildfires have become <a href="https://theconversation.com/california-wildfires-signal-the-arrival-of-a-planetary-fire-age-125972">annual events in California</a> in an ever-expanding fire season. Los Angeles residents have received <a href="https://twitter.com/southcoastaqmd/status/1441143300308627458">warnings</a> about the <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">health risks of wildfire smoke</a>, which can cause lung damage and worsen cardiovascular problems like heart disease and stroke with heavy or long-term exposure. These health risks may explain why Angelenos are increasingly curtailing outdoor activities when wildfires are burning.</p>
<p><iframe id="Ta5Ik" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/Ta5Ik/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Exposed to heat at home and work</h2>
<p>Southern California is no stranger to heat, but the frequency, intensity and length of its heat waves have <a href="https://doi.org/10.1029/2020EF001480">increased substantially since the 1950s</a>, especially in urban areas like Los Angeles County. Los Angeles experienced multiple heat waves in the summer and fall of 2021, with <a href="https://laist.com/news/climate-environment/another-weekend-another-heat-wave-for-la">triple-digit temperatures in many zones</a>.</p>
<p>By 2050, Los Angeles expects up to a <a href="https://ceo.lacounty.gov/wp-content/uploads/2021/10/LA-County-Climate-Vulnerability-Assessment-1.pdf">tenfold increase</a> in the frequency of extreme heat waves. This equates to over five heat waves per year compared with the historic average of less than one per year. </p>
<p>This forecast poses troubling implications for health equity in the region. According to our data, vulnerability to heat is unequally distributed across the population. Black residents are significantly more likely than white residents to be exposed to heat at home and at work. </p>
<p><iframe id="pSvRu" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/pSvRu/4/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>At home, rates of access to air conditioning are heavily stratified by race. Asian and white residents are the most likely to report having air conditioning in their homes (90% and 87%, respectively), while Black residents are the least likely to have this amenity (66%).</p>
<p>At work, approximately 27% of Black residents report working outdoors without cover – for example, from a tent or booth – compared with 18% of Hispanic residents, 15% of white residents and 10% of Asian residents. Prolonged heat exposure, especially without the opportunity to cool off overnight, is a <a href="https://theconversation.com/3-tips-for-preventing-heat-stroke-164055">serious health risk</a>.</p>
<p><iframe id="e5JXH" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/e5JXH/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Expensive and stressful</h2>
<p>Our survey also reveals that climate change is affecting Angelenos’ financial and mental health. According to self-reported data, nearly 10% of residents saw an increase in their utility expenses, 4.4% lost income and 3.1% suffered health problems because of a natural disaster such as wildfire, flooding or extreme heat in the past year. </p>
<p>Living in Los Angeles has never been risk-free: Earthquakes are a well-known hazard here and elsewhere in California. But climate change is magnifying other threats, such as wildfires, droughts and heat waves. All of these events can damage property, threaten residents’ health and safety and force some people from their homes.</p>
<p><iframe id="U0VEx" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/U0VEx/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Natural disasters can also trigger various forms of psychological distress. Over 1 in 4 Angelenos reported experiencing some form psychological distress over the past 12 months because of a natural disaster, including anxiety, depression, prolonged fatigue or high stress. </p>
<p>These mental health impacts were most pronounced among young and low-income residents. Angelenos with a household income below $30,000 per year were almost twice as likely as those with higher incomes to report psychological distress due to a natural disaster. Likewise, compared with Angelenos ages 60 and older, more than twice as many Angelenos under age 40 reported experiences of psychological distress due to a natural disaster. </p>
<p><iframe id="3fwrq" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/3fwrq/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>The climate crisis is a social and economic crisis</h2>
<p>As cities and counties around the country brace for more extreme climate conditions, our findings in Los Angeles show that extreme weather can have serious social and economic impacts. In the span of just the past year, climate change has left millions of Americans isolated and financially or psychologically distressed.</p>
<p>Adapting to these risks isn’t just a matter of weatherizing homes and educating the public about climate hazards. Local governments also need to prepare for inevitable strains on social and health care systems as climate conditions make it increasingly difficult for people to meet their most basic needs.</p>
<p>[<em>More than 140,000 readers get one of The Conversation’s informative newsletters.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140K">Join the list today</a>.]</p><img src="https://counter.theconversation.com/content/173408/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kyla Thomas is the director of the USC Dornsife-Union Bank LABarometer, which is designed and administered by the USC Dornsife Center for Economic and Social Research with funding from MUFG Union Bank.</span></em></p>Southern California is on the front line of climate change, and recent survey data shows that residents are feeling its effects in many ways.Kyla Thomas, Sociologist, USC Dornsife College of Letters, Arts and SciencesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1725052021-12-09T13:29:02Z2021-12-09T13:29:02ZCurious Kids: If steam contains water, what does smoke from fire contain?<figure><img src="https://images.theconversation.com/files/433661/original/file-20211124-25-p99tno.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Toa55/Shutterstock</span></span></figcaption></figure><p><em>Curious Kids is <a href="https://theconversation.com/africa/topics/curious-kids-36782">a series</a> for children in which we ask experts to answer questions from kids.</em></p>
<p><strong>If steam contains water, which goes up and evaporates, what does smoke from fire contain? (Amasi-Mario, 8, Nigeria)</strong></p>
<p>You’ve asked an important question, Amasi-Mario: this is something that lots of people around the world have also wondered. As a scientist <a href="http://archibaldlab.weebly.com/team.html">who studies</a> how fires happen in natural spaces like savannas and forests, and what they can do to the environment, I’m one of those people. </p>
<p>Living in Nigeria, you’ve probably seen lots of fires; some in your own home to keep you warm, and some burning through the bush. You will have noticed that not all fires make the same sort of smoke. There are a few reasons for this – let me explain. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a> is a series by <a href="https://theconversation.com/uk">The Conversation</a> that gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskids@theconversation.com">curiouskids@theconversation.com</a>. We won’t be able to answer every question, but we’ll do our very best.</em></p>
<h2>What is in smoke</h2>
<p>When fires burn they are “consuming” plants. After a fire the vegetation that was there before has gone, and plants have to grow again from their roots or seeds. However, that plant material has not just disappeared: a lot of it has gone up into the sky as smoke. Big wildfires like we have in our African savannas can make so much smoke that it seems as if the smoke is making clouds in the sky. That’s probably why you asked the question about steam and smoke.</p>
<p>Quite a lot of the smoke from a fire is actually steam. All the water in the plant gets evaporated by the heat of the flames, and goes up in the smoke as water vapour. Once the water is gone then the leaves and the stems of the plants burn, and turn into a gas called carbon dioxide. </p>
<p>When fires burn plants they are doing exactly the same thing our bodies do when we eat plants: they are releasing the energy stored in the plant. We eat food and breathe in oxygen. The oxygen joins to the carbon from the food, and makes carbon dioxide that we breathe out. This gives us energy. Fires also need oxygen to “eat” plants. Sometimes when they don’t have enough oxygen they breathe out carbon monoxide or methane instead of carbon dioxide, but all of these gases go up into the air in the smoke. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-is-fire-100490">Curious Kids: what is fire?</a>
</strong>
</em>
</p>
<hr>
<p>However, not every bit of the plant is turned into carbon dioxide in a fire. Some very small particles of ash and soot are not burned, but are taken up into the sky with the water vapour and the carbon dioxide. We call these <a href="https://www.sciencenewsforstudents.org/article/explainer-what-are-aerosols">aerosols</a>: tiny particles that are light enough to stay up in the sky even though they are not a gas. These aerosols are what gives smoke its grey or black colour sometimes. </p>
<p>So, just as water moves around the world as a “<a href="https://gpm.nasa.gov/education/water-cycle">water cycle</a>” – changing from solid to liquid to gas with the help of energy from the sun – carbon also moves around the world in a “carbon cycle”. Fire is part of that cycle, turning solid carbon in plants back into carbon dioxide gas. We breathe out carbon dioxide gas when we eat plants, and fire “breathes out” carbon dioxide gas and other small particles when it burns plants.</p>
<h2>Learning more</h2>
<p>As I said earlier, you can see that not all fires make the same sort of smoke. This is because the amount of aerosols, water vapour, and other gases that come from a fire changes depending on the weather and what sorts of plants are being burned. At the moment I and other scientists are studying fires in Africa at different times of year: we want to see how the smoke from these fires changes over the year. </p>
<p>The way we do this is pretty cool. We fly small helicopters called drones into the smoke and catch packets of the smoke so that we can see what it is made of. There isn’t an actual person flying the drones – that would be dangerous, so the drones are controlled with remotes like you’d use for your TV.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/oUuqiKJfNN4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Scientists flying a drone into a fire so they can study the smoke.</span></figcaption>
</figure>
<p>We take these smoke samples back to the lab and work out how much water vapour, carbon dioxide, and aerosols are in the smoke. This helps us to understand the carbon cycle better, and decide when and how to burn our land so that the smoke doesn’t cause damage to people or the environment.</p><img src="https://counter.theconversation.com/content/172505/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sally Archibald does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Scientists are studying fires in Africa at different times of year to see how the smoke from these fires changes over the year.Sally Archibald, Professor of Ecology, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1658662021-11-12T13:36:08Z2021-11-12T13:36:08ZNeurotoxins in the environment are damaging human brain health – and more frequent fires and floods may make the problem worse<figure><img src="https://images.theconversation.com/files/428985/original/file-20211028-23-ey0fbd.jpg?ixlib=rb-1.1.0&rect=242%2C177%2C3352%2C2204&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wildfire smoke contains a mixture of toxic pollutants that can be harmful to both the lungs and the brain. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/california-wildfires-royalty-free-image/1281624333?adppopup=true">Bloomberg Creative/ Bloomberg Creative Photos via Getty Images</a></span></figcaption></figure><p>In the summer of 2021, a toxic, smoky haze stemming from <a href="https://www.nbcnews.com/western-wildfires">Western wildfires</a> wafted across large parts of the United States, while hurricanes wrought extensive flooding in the southern and eastern U.S. Air quality websites such as <a href="https://www.airnow.gov">AirNow</a> warned of <a href="https://www.npr.org/2021/07/21/1018865569/the-western-wildfires-are-affecting-people-3-000-miles-away">hazardous conditions</a> on the U.S. East Coast from Western forest fires 3,000 miles away, with recommendations to stay indoors. </p>
<p>Journalists reported the immediate impact of lives lost and homes and property destroyed, but more insidious dangers escaped notice. Few people realize that these <a href="https://www.npr.org/2021/09/11/1035241392/climate-change-disasters-mental-health-anxiety-eco-grief">climate change-fueled</a> <a href="https://www.washingtonpost.com/world/interactive/2021/cop26-extreme-weather-climate-change-action/">disasters</a> – both fires and <a href="https://doi.org/10.1080/10807030903051309">floods</a> – could <a href="https://doi.org/10.1080/10962247.2017.1401017">adversely affect human health</a> in longer-term ways. </p>
<p>I’m a <a href="https://scholar.google.com/scholar?as_ylo=2017&q=Arnold+Eiser&hl=en&as_sdt=0,39">scientist-author</a> who studies the links between environmental factors and the development of neurological disorders, which is the <a href="https://rowman.com/ISBN/9781538158074/Preserving-Brain-Health-in-a-Toxic-Age-New-Insights-from-Neuroscience-Integrative-Medicine-and-Public-Health">subject of my recent book</a>. My <a href="https://doi.org/10.1016/j.brainres.2017.06.032">research on this topic</a> adds to a growing body of evidence that <a href="https://www.nytimes.com/2019/07/15/climate/flooding-chemicals-health-research.html">more frequent environmental disasters</a> may be raising <a href="https://doi.org/10.1007/s11356-015-4913-9">human exposure to neurotoxins</a>.</p>
<h2>Neurotoxic smoke</h2>
<p>Many scientists have identified links between <a href="https://doi.org/10.1016/j.bj.2018.06.001">air pollution</a> in various forms, including from <a href="https://theconversation.com/breathing-wildfire-smoke-can-affect-the-brain-and-sperm-as-well-as-the-lungs-166548">forest fire smoke</a>, and an increased risk and prevalence of adverse health effects, including brain disorders. </p>
<p>Wildfire smoke is a mixture of <a href="https://health.ny.gov/environmental/outdoors/air/smoke_from_fire">countless noxious chemical compounds</a>. Fires burning <a href="https://www.theguardian.com/world/2021/aug/09/fires-rage-around-the-world-where-are-the-worst-blazes%20and%20Australia">across the warming planet</a> – from California to Greece and Australia – are adding dangerous particulate matter to the atmosphere that includes <a href="https://doi.org/10.5772/intechopen.97204">neurotoxic heavy metals</a> such as mercury, lead, cadmium and manganese nanoparticles. <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">These toxins</a> are an added environmental burden on top of the pollutants emitted by factories, power plants, trucks, automobiles and other sources. </p>
<p>The greatest potential for health problems comes from minuscule particles, smaller than 2.5 microns – or PM 2.5 (for context, the width of a human hair is typically 50 to 70 microns). This is, in part, because <a href="https://doi.org/10.1164/rccm.201903-0635LE">tiny particles are easily inhaled</a>; from the lungs, they enter the bloodstream and circulate widely throughout the body. <a href="https://doi.org/10.3389/fphys.2020.00155">In the brain</a> they may inflame the microglial cells, the brain’s defensive cells, causing harm to neurons instead of protecting them. Studies show that these extremely tiny particles may damage neurons or brain cells by <a href="https://doi.org/10.1016/j.tins.2009.05.009">promoting inflammation</a>. Brain inflammation can lead to conditions <a href="https://doi.org/10.3233/JAD-180631">like dementia</a> and <a href="https://doi.org/10.1097/JOM.0000000000000451">Parkinson’s disease</a>, a movement disorder in adults.</p>
<p>In addition, <a href="https://doi.org/10.1001/jamapediatrics.2018.3101">prenatal</a> and <a href="https://doi.org/10.1097/EDE.0000000000001109">early-life exposure</a> to air pollution has been linked to an increased risk of autism spectrum disorder in children. Research suggests that <a href="https://doi.org/10.1001/jamanetworkopen.2021.7508">air pollution exposure</a> during these critical periods, particularly in the third trimester of pregnancy and the first few months of life, <a href="https://doi.org/10.1515/tnsci-2016-0005">may impair normal neural development</a>. </p>
<h2>Waterborne neurotoxins</h2>
<p>As part of my book research, I investigated potential links between environmental neurotoxins and related health effects in Finland. Seeking unique environmental factors that might underlie the disproportionately high rates of fatal dementia that occurred in Finland in the past decade, I found that <a href="https://doi.org/10.1016/j.brainres.2017.06.032">water pollution</a> – exacerbated by flooding, use of fertilizer and higher water temperatures – may be affecting brain health. </p>
<p>As I reviewed the environmental concerns in Finland, the widespread presence of <a href="https://www.usgs.gov/centers/kswsc/science/cyanobacterial-blue-green-algal-blooms-tastes-odors-and-toxins-0?qt-science_center_objects=0#qt-science_center_objects">blue-green algae in waterways</a> stood out to me. Though it’s commonly called algae, blue-green algae is actually a type of bacteria called cyanobacteria. These toxic microorganisms thrive and proliferate in warm waterways when excessive nutrients, particularly phosphorus from fertilizer runoff, pour into fresh and brackish water. It produces <a href="https://www.epa.gov/cyanohabs/health-effects-cyanotoxins">cyanotoxins</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Blue-green algae bloom on surface of lake with trees in the distance." src="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=468&fit=crop&dpr=1 754w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=468&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=468&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Harmful blooms of blue-green algae on lakes and ponds can be toxic to humans and dogs alike.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sefton-park-lake-in-liverpool-which-has-been-closed-off-news-photo/1228294229?adppopup=true">Peter Byrne/PA Images via Getty Images</a></span>
</figcaption>
</figure>
<p>One of these cyanotoxins, β-methylamino-L-alanine, or BMAA, is linked to <a href="https://doi.org/10.3389/fnagi.2020.00026">neurodegenerative disorders</a> including amyotrophic lateral sclerosis, or ALS, Parkinson’s disease and Alzheimer’s disease.
In particular I was struck by scientists’ finding high levels of BMAA in <a href="https://doi.org/10.1073/pnas.0914417107">mollusks and fish found in the Baltic Sea</a>, which could potentially play a role in Finland’s high incidence of dementia, as fish is heavily consumed there.</p>
<p>Blue-green algae is found in <a href="https://www.cdc.gov/habs/index.html">rivers, lakes and seas</a>. Its presence is a widespread problem for humans, dogs and wildlife in the U.S. and Canada, as well as around the globe. In 2020, <a href="https://www.bbc.com/news/world-africa-54234396">more than 300 elephants in Botswana died</a> after drinking from water sources contaminated by the cyanobacteria that cause these algal blooms. Blue-green algae is so widely present in Finland that scientists there have developed <a href="https://www.utu.fi/en/news/news/novel-testing-device-will-reveal-whether-water-contains-toxic-blue-green-algae">a quick test to determine whether it is present or not.</a></p>
<h2>Mold neurotoxins</h2>
<p>In Finland, warm, humid air creates the perfect conditions for mold to grow, and water-damaged buildings are particularly susceptible. Some species emit mycotoxins, or mold toxins. Long-term exposure to mycotoxins, even at low levels, can present <a href="https://doi.org/10.1080/00039896.2003.11879142">serious health hazards</a> for both people and animals. </p>
<p>Mold spores are tiny, making them easy to inhale or ingest. Inside the body they can trigger an immune response, leading to chronic inflammation. Ultimately, exposure to these spores may cause <a href="https://doi.org/10.1016/j.shaw.2020.01.003">cognitive impairment</a>, including memory loss, irritability, numbness, tremors and other symptoms. Such a situation is likely to develop after a region has experienced the flooding of residences or workplaces in the weeks after they have been damaged.</p>
<p>Mold toxins, particularly <a href="https://doi.org/10.1002/mnfr.200600137">ochratoxin A</a>, can trigger inflammation that may harm neurons and brain function. It has been <a href="https://doi.org/10.1016/j.jns.2006.06.006">specifically implicated</a> in Parkinson’s disease. </p>
<h2>Reducing risk and a way forward</h2>
<p>Education, greater awareness of environmental health concerns and public action are the best ways to minimize risks from environmental neurotoxins.</p>
<p>By learning to recognize blue-green algae, people may avoid swimming or boating near it and avoid letting their pets near it too. Consumers can advocate for greater environmental monitoring of food and water sources. Exercise that involves sweating can <a href="https://doi.org/10.1155/2017/3676089">help eliminate neurotoxic substances</a>. But before you exercise outdoors, it is prudent to check air quality on an app or website like <a href="https://www.airnow.gov/">AirNow</a>, a partnership of federal, state, local and tribal agencies.</p>
<p>If environmental policies aren’t put into place to mitigate the health risks posed by environmental neurotoxins, <a href="https://doi.org/10.4172/2161-0460.1000249">research suggests</a> that we may continue to experience increases in a variety of neurodegenerative disorders as the toxins rise. Many of these conditions are labeled idiopathic, or lacking a known cause. The neurotoxic connection is rarely considered, and environmental health hazards are <a href="https://doi.org/10.1186/s12909-020-02458-x">often overlooked in American health care</a>. This is in large part because environmental health is rarely taught in medical education, which can lead to a lack of awareness about potential diagnoses related to an environmental illness.</p>
<p>The U.S. Environmental Protection Agency is currently <a href="https://www.epa.gov/system/files/documents/2021-10/draft-policy-assessment-for-the-reconsideration-of-the-pm-naaqs_october-2021_0.pdf">reevaluating</a> air quality standards for particulate matter. A new EPA <a href="https://www.epa.gov/system/files/documents/2021-09/_epaoig_20210929-21-e-0264.pdf">inspector general report</a> calls for a strategic plan to control harmful algal blooms. Ohio, a leading state for public policy initiatives aimed at neurotoxic algal blooms, <a href="https://grist.org/politics/toxic-algae-blooms-are-multiplying-the-government-has-no-plan-to-help">now regulates</a> cyanotoxins in drinking water and advises farmers against adding fertilizer when the ground is saturated or when rain is in the forecast. </p>
<p>Since <a href="https://doi.org/10.1038/s41586-019-1468-9">climate change may be a driver for rising neurotoxins</a>, cutting greenhouse gas emissions and ensuring better environmental stewardship are essential to human health. Achieving this will require strong international and domestic efforts and a wide range of interventions by governments around the world. But all of these efforts must begin with a deeper and more widespread understanding of the profound nature of this problem – which should be a universal, nonpartisan concern. </p>
<p>[<em>Over 115,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-newsletter-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p><img src="https://counter.theconversation.com/content/165866/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnold R. Eiser does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Pollution from more frequent floods and wildfires – exacerbated by the warming climate – is threatening human health and poses particular risks to the brain.Arnold R. Eiser, Emeritus Professor of Medicine, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1665482021-08-30T12:33:58Z2021-08-30T12:33:58ZBreathing wildfire smoke can affect the brain and sperm, as well as the lungs<figure><img src="https://images.theconversation.com/files/418289/original/file-20210827-15-2ilngf.jpg?ixlib=rb-1.1.0&rect=0%2C202%2C4782%2C3113&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A runner wears a respirator on a smoky day in Portland, Oregon, in 2020.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/local-resident-wears-a-respirator-as-he-jogs-in-downtown-news-photo/1228516107">Robyn Beck/AFP via Getty Images</a></span></figcaption></figure><p>Wildfires burning in the western U.S. are sending smoke into communities far from the fires themselves, creating hazardous air for days or weeks at a time. A lot of people are wondering: What does breathing all that smoke do to our bodies?</p>
<p>Wildfire smoke is a <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">mix of chemicals</a> and tiny particles that are <a href="https://www.epa.gov/pm-pollution/particulate-matter-pm-basics">small enough</a> to evade the body’s defenses and directly affect the lungs. But the damage may not stop there.</p>
<p>As <a href="https://www.researchgate.net/profile/Luke-Montrose-2">environmental</a> <a href="https://www.researchgate.net/profile/Adam-Schuller">toxicologists</a>, we have been investigating the health effects of wildfire smoke on humans, including on parts of the body that you might not expect: sperm and the brain.</p>
<p>Given the <a href="https://doi.org/10.1029/2018GH000144">large number of people</a> now breathing wildfire smoke each summer – numbers that are likely to increase as <a href="https://nca2018.globalchange.gov/chapter/6/">wildfire conditions worsen</a> in a warming world – it’s important to understand how wildfire smoke can harm your body and how to protect yourself.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of wildfire smoke showing thickest smoke across large parts of California, Nevada, Utah, Oregon and Washington" src="https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418313/original/file-20210828-27-h51zzw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Smoke from large western wildfires was detected as far east as the Dakotas on Aug. 28, 2021.</span>
<span class="attribution"><a class="source" href="https://fire.airnow.gov/#">Interagency Wildland Fire Air Quality Response Program, EPA</a></span>
</figcaption>
</figure>
<h2>Pollution can change sperm’s genetic material</h2>
<p>Urban air pollution, which has a slightly different chemical profile than wildfire smoke, has already been linked with harmful effects to the male reproductive system. Studies have shown how air pollution produced from sources like industrial stacks and automobile exhaust can <a href="https://doi.org/10.1515/reveh-2020-0136">affect sperm shape, their ability to swim and the genetic material they carry</a>. However, <a href="https://doi.org/10.1038/s41467-021-21708-0">few studies</a> have looked at wildfire smoke as an independent source of toxicity.</p>
<p>One recent study found that baby rats born to parents that had been exposed to wood smoke could <a href="https://doi.org/10.3390/toxics9010003">end up with behavioral and cognitive problems</a>. That prompted our team at Boise State University, in collaboration with researchers at Northeastern University, to look closer at what happens to sperm of mice exposed to wildfire smoke.</p>
<p>Our goal was to look for small changes at the cellular level that might show us how negative effects could be passed from parents to the next generation. Mice aren’t humans, of course, but damage to their systems can provide clues about potential harm to ours.</p>
<figure class="align-center ">
<img alt="An older man with a cane crosses n empty road in smoky conditions." src="https://images.theconversation.com/files/418290/original/file-20210827-27217-1e796le.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418290/original/file-20210827-27217-1e796le.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418290/original/file-20210827-27217-1e796le.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418290/original/file-20210827-27217-1e796le.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418290/original/file-20210827-27217-1e796le.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418290/original/file-20210827-27217-1e796le.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418290/original/file-20210827-27217-1e796le.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Exposure to wildfire smoke can also harm the lungs, heart and brain.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/man-walks-along-ventura-ave-as-the-thomas-fire-leaves-smoke-news-photo/888932848">Wally Skalij/Los Angeles Times via Getty Images</a></span>
</figcaption>
</figure>
<p>We simulated a wildland fire in the laboratory by burning Douglas fir needles and chose a smoke exposure amount similar to what a wildland firefighter with 15 years of service would experience. We found that this exposure in a mouse <a href="https://www.mdpi.com/2305-6304/9/9/199">resulted in changes in sperm DNA methylation</a>. DNA methylation is a biological mechanism that can regulate how a gene is expressed, kind of like a dimmer switch on a light bulb. Environmental factors can influence DNA methylation, and this can be <a href="https://doi.org/10.1002/em.22311">harmful</a> if it occurs at the wrong time of life or at the wrong gene.</p>
<p>We were surprised to find that the effects of wood smoke were similar to the effects of <a href="https://doi.org/10.1038/s41598-020-72783-0">cigarette and cannabis smoke exposure</a> on sperm. Much more work is still needed to understand if and how these changes in sperm affect the offspring they create, and what the effect is in humans. Studying populations with extreme levels of smoke exposure, like wildland firefighters, would help to answer these questions. However, very <a href="https://doi.org/10.1016/j.ccm.2020.08.017">little data currently exists</a> for long-term exposure monitoring and health tracking in this group of workers. </p>
<h2>Links to Alzheimer’s and other ways smoke affects the brain</h2>
<p>Wood smoke exposure has also been linked to poor brain health, including conditions like Alzheimer’s disease. There is data that suggests wood smoke exacerbates symptoms of cognitive decline such as <a href="https://doi.org/10.1016/j.bj.2018.06.001">loss of memory or motor skills</a>.</p>
<p>In a recent <a href="https://doi.org/10.1177/2516865720954873">review article</a> in the journal Epigenetics Insights, we outlined the latest research showing how wildfire smoke particles or the inflammatory signals released by the immune system after exposure might reach the brain and contribute to these health problems. </p>
<p>One possibility is for very small particles to be inhaled into the lungs, escape into the blood stream and travel to the brain. A second possibility is the particles stay in the lungs but generate inflammatory signals that travel in the blood to the brain. Lastly, evidence suggests that particles may not need to travel to the lungs at all, but rather could get to the brain <a href="https://doi.org/10.1177/0192623317729222">directly from the nose</a> by following nerve bundles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration showing PM2.5 compared to a human hair's width." src="https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=409&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=409&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418280/original/file-20210827-24-18b0u3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=409&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wildfire smoke particles include PM2.5 particulate matter that is much smaller than a human hair.</span>
<span class="attribution"><a class="source" href="https://ww2.arb.ca.gov/wildfire-smoke-health">California Air Resources Board</a></span>
</figcaption>
</figure>
<p>DNA methylation changes are especially crucial in brain areas like the hippocampus that are involved in learning and memory. If environmental exposures are changing DNA methylation, that may <a href="https://doi.org/10.1186/s13148-020-00893-7">help to explain</a> why Alzheimer’s disease can affect only one identical twin even though their genetic code is exactly the same.</p>
<h2>What can you do to stay safe?</h2>
<p>The potential impact of breathing wildfire smoke on lungs alone should be concerning enough to make people think twice about their level of exposure. Now, we’re seeing the potential for additional risks, including to the sperm and brain. Other research suggests connections between wildfire smoke and <a href="https://doi.org/10.1186/s12989-020-00394-8">heart inflammation</a> and the risk of <a href="https://doi.org/10.1016/j.envres.2021.111872">pre-term births</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">What's in wildfire smoke? A toxicologist explains the health risks and which masks can help</a>
</strong>
</em>
</p>
<hr>
<p>So, what can you do to lower your health risk during wildfire season?</p>
<p>Start by staying alert to wildfire smoke warnings. The <a href="https://www.airnow.gov/">Environmental Protection Agency</a> and companies like <a href="https://www2.purpleair.com/">PurpleAir</a> have robust air monitoring networks with interactive maps that can show you how bad or good the air quality is in your area. You can also find low-cost air quality monitors.</p>
<p>In your home, change the filter on your furnace and air conditioner regularly and make sure it is the proper size. Portable HEPA air purification units in the rooms you spend the most time in can help, too.</p>
<p>Face masks can be a great tool when used properly. A mask labeled N-95 or higher is <a href="https://doi.org/10.1038/s41370-020-00267-4">designed to filter</a> out 95% or more of the harmful particles that get deep into the lungs, but only if they have the proper fitment. While cloth masks can help <a href="https://doi.org/10.1073/pnas.2014564118/">stop the spread of COVID-19</a>, they do not do a good job of filtering out wildfire smoke particles. This is partly because they don’t seal well on the face and because the material is not designed to capture dangerously small smoke particles.</p>
<p>As the planet warms and the West continues to dry, wildfire smoke is likely to become a common feature of summer. It’s important to understand the health risks so you can protect yourself.</p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p><img src="https://counter.theconversation.com/content/166548/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Montrose receives funding from the technology access award provided by the Data Science core of the Idaho INBRE program under NIH/NIGMS Grant #P20GM103408 and Boise State COBRE program in Matrix Biology through NIH/NIGMS Grant #P20GM109095.</span></em></p><p class="fine-print"><em><span>Adam Schuller receives funding from the technology access award provided by the Data Science core of the Idaho INBRE program under NIH/NIGMS Grant #P20GM103408 and Boise State COBRE program in Matrix Biology through NIH/NIGMS Grant #P20GM109095.</span></em></p>To stay healthy, it’s important to understand how wildfire smoke can harm your body and how to protect yourself.Luke Montrose, Assistant Professor of Community and Environmental Health, Boise State UniversityAdam Schuller, Researcher in Biomolecular Sciences, Boise State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1663262021-08-19T18:01:20Z2021-08-19T18:01:20ZSmoke seasons aren’t new but our efforts to control wildfires are — and should change<p>Like many people, I will remember this summer in shades of grey and red. As snapshots of a dull orange sun circulated social media, “<a href="https://www.nationalgeographic.com/environment/article/zombie-fires-in-the-arctic-are-linked-to-climate-change">zombie fires</a>” rose from the Russian permafrost, <a href="https://www.theguardian.com/world/2021/jul/25/lytton-canada-heat-wildfire-record-temperatures">entire towns were wiped off the map</a> and Southern Europe became a <a href="https://www.theguardian.com/world/2021/aug/07/apocalyptic-scenes-hit-greece-as-athens-besieged-by-fire">scene of the apocalypse</a>. </p>
<p>Satellites tracked enormous plumes of wildfire smoke across North America, the Atlantic Ocean and the Arctic Circle until they <a href="https://www.theguardian.com/world/2021/aug/09/smoke-siberia-wildfires-reaches-north-pole-historic-first">reached the North Pole</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1426985074449391621"}"></div></p>
<p>Although the 2021 smoke season is in many ways unprecedented, smoke seasons themselves are not new. Western North America is particularly susceptible to smoke because Pacific winds carry it up and down the continent among active fire ecosystems in California, Oregon, Washington, British Columbia and Alaska.</p>
<p>Newspapers from <a href="https://archive.org/details/dailycolonist0726uvic_35">1926</a>, <a href="https://www.newspapers.com/image/499805730/">1945</a>, <a href="https://www.newspapers.com/image/492331235/">1958</a> and <a href="https://archive.org/details/dailycolonist19670819/1967_08_19">1967</a> included complaints from British Columbians about the veil of smoke from forest fires. These were later corroborated by the <a href="https://doi.org/10.3389/fevo.2019.00090">layers of black carbon</a> found in <a href="https://doi.org/10.1191%2F0959683606hl920rp">ice and sediment cores</a> taken from <a href="https://doi.org/10.5194/cp-10-1905-2014">glaciers</a> and <a href="https://doi.org/10.1890/060161">lake beds</a>.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Historic photograph of men fighting fire with buckets" src="https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=840&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=840&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=840&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1055&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1055&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416937/original/file-20210819-21-162jm15.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1055&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fighting forest fire with buckets in Ontario in 1911.</span>
<span class="attribution"><span class="source">(William Ready Division of Archives and Research Collections)</span></span>
</figcaption>
</figure>
<p>As an environmental historian, I use archival documents — photographs, forest service records, media accounts, oral interviews — to learn about large-scale smoke events in the past. In one of the <a href="https://www.uap.ualberta.ca/titles/194-9781772120035-chinchaga-firestorm">best documented</a> examples, smoke from an enormous fire in the Peace River district in northern British Columbia and Alberta choked the entire northern hemisphere in 1950. As the giant plume drifted east, it left a trail of anxious headlines behind it.</p>
<p>In New York: “<a href="https://www.nytimes.com/1950/09/25/archives/forest-fires-cast-pall-on-northeast-canadian-drift-600-miles-long.html?smid=em-share">Forest Fires Cast Pall On Northeast; Canadian Drift 600 Miles Long Darkens Wide Areas and Arouses ‘Atom’ Fears</a>.” In Edinburgh: “<a href="https://www.britishnewspaperarchive.co.uk/viewer/bl/0001542/19500927/068/0004">Scots See Blue Sun, Fear End of World</a>.” And in Oslo: “Solen og månen ble koboltblå!” (“The sun and the moon became cobalt blue!”). By October 1950, the smoke had circumnavigated the Earth.</p>
<p>If smoke seasons are not new, what makes this summer different?</p>
<h2>Wildfire smoke difficult to regulate</h2>
<p>Climate change makes <a href="https://doi.org/10.1088/1748-9326/aa5835">wildfire seasons longer</a> and <a href="https://cfs.nrcan.gc.ca/pubwarehouse/pdfs/37108.pdf">more intense</a>, but our checkered history of how we address smoke makes controlling it difficult.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-years-of-fighting-every-wildfire-helped-fuel-the-western-megafires-of-today-163165">How years of fighting every wildfire helped fuel the Western megafires of today</a>
</strong>
</em>
</p>
<hr>
<p>Before clean air regulations came into effect in Europe, Canada and the United States, industrial smoke was common in cities. Wildfire smoke was just one more pollutant in already grey skies. This was especially true for working class and racialized people, who often lived near smoke-producing factories.</p>
<p>During summer, wildfire smoke could make industrial smoke worse. In 1937, in an address to the annual conference of the Scottish branch of the National Smoke Abatement Society, John R. Currie, a professor of public health at Glasgow University, argued that <a href="https://www.britishnewspaperarchive.co.uk/viewer/bl/0000540/19370522/297/0020">wildfire smoke from Idaho had worsened industrial pollution</a> for the cities in its path.</p>
<figure class="align-center ">
<img alt="Satellite view of the Earth and wildfire smoke" src="https://images.theconversation.com/files/416802/original/file-20210818-17-1su07o3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416802/original/file-20210818-17-1su07o3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=390&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416802/original/file-20210818-17-1su07o3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=390&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416802/original/file-20210818-17-1su07o3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=390&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416802/original/file-20210818-17-1su07o3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=490&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416802/original/file-20210818-17-1su07o3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=490&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416802/original/file-20210818-17-1su07o3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=490&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wildfire smoke spreads across the globe.</span>
<span class="attribution"><span class="source">(NOAA)</span></span>
</figcaption>
</figure>
<p>At the time, <a href="https://doi.org/10.7202/1059114ar">public health initiatives recognized that smoke was harmful</a>, but there was little regulators could do about the smoke drifting out of the forests. Anti-pollution legislation and the introduction of new cleaner-burning fuels gradually <a href="https://www.fraserinstitute.org/sites/default/files/canadas-air-quality-since-1970-an-environmental-success-story.pdf">reduced visible industrial pollution</a> in most cities, but wildfire smoke remained a periodic problem.</p>
<h2>Forests depend on fire</h2>
<p>Historians have documented the long history of fire suppression in western North America. In British Columbia, the public believed that fire fighting technology would one day completely eliminate wildfire and smoke. For example, one of the first actions of the <a href="https://www.for.gov.bc.ca/hfd/pubs/docs/mr/annual/ar_1911-30/annual_1912.pdf">newly created Forest Service in British Columbia in 1912</a> was to create a permit system for burning.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Editorial cartoon of a knight on a horse, marked Forest Service, fighting a dragon on the edge of a forest." src="https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=433&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=433&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=433&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=544&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=544&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416789/original/file-20210818-27-1q9pdrk.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=544&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The public thought fire fighting technology would eliminate wildfire and smoke entirely.</span>
<span class="attribution"><span class="source">(Victoria Daily Times)</span></span>
</figcaption>
</figure>
<p>“Slash burning” was still used to dispose of logging waste — <a href="https://www2.gov.bc.ca/gov/content/environment/air-land-water/air/air-pollution/smoke-burning/industrial">the leftover tree limbs and other residues are called slash</a> — but became tightly controlled. When slash fires escaped and burned communities, like the <a href="https://www.cbc.ca/news/canada/british-columbia/how-people-lost-homes-in-fires-decades-ago-feel-today-1.5171630">Gleneden fire of 1973</a>, slash burning developed a negative reputation. </p>
<p>Over the years, experts proposed alternatives to burning such as chipping or <a href="https://nature.berkeley.edu/news/2020/09/benefits-cattle-grazing-reducing-fire-fuels-and-fire-hazard">cattle grazing</a> to reduce landscape fuel, methods that had been used successfully elsewhere. However, the size and extent of Western Canada’s forests means slashing remains the primary method for clearing flamable logging waste, <a href="https://thenarwhal.ca/up-in-smoke-b-c-backtracks-on-promise-to-deter-logging-industry-from-burning-wood-waste/">despite ongoing</a> <a href="https://www.cbc.ca/news/canada/british-columbia/province-wide-slash-burning-sparks-controversy-1.3652496">criticism</a>.</p>
<p>We now know that <a href="https://www2.gov.bc.ca/gov/content/safety/wildfire-status/prevention/vegetation-and-fuel-management/prescribed-burning">western ecosystems require</a> frequent, low-intensity fire to remain healthy and balanced. Decades of fire suppression has created more explosive and unpredictable conditions. Despite rapid advances in fire detection and fire fighting technology, fire seasons have gotten worse, not better.</p>
<p>Now experts are calling for <a href="https://www.nationalgeographic.com/environment/article/more-good-fire-could-help-california-control-future-catastrophes">more prescribed burns</a> to restore fire to the land and mitigate modern smoke seasons. There is <a href="https://doi.org/10.1016/j.jenvman.2021.112568">good scientific evidence</a> to <a href="https://doi.org/10.1073/pnas.2105073118">support them</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-indigenous-burning-practices-can-help-curb-the-biodiversity-crisis-165422">How Indigenous burning practices can help curb the biodiversity crisis</a>
</strong>
</em>
</p>
<hr>
<p>According to these experts, the question is not whether or not we should have smoke in the atmosphere, but when and how much of it we want to breathe. Yet most of places where forest fires pose the biggest threat have yet to implement prescribed burns on a wide scale. For example, the <a href="https://drive.google.com/file/d/1dJgDaS8yLYx5UusAxz7BNnacY_B4ptSB/view">Prescribed Fire Council’s 2020 report</a> shows that the American West lags behind the Southeast. Prescribed fire is not widely used in <a href="https://doi.org/10.1890/120298">Southern Europe</a> or <a href="https://www.pc.gc.ca/en/nature/science/conservation/feu-fire/feuveg-fireveg/dirige-prescribed/projet-projects">Canada</a>.</p>
<h2>The future is smoky</h2>
<p>Significant barriers remain to returning fire and smoke to our lives. In the past, people believed forest fire smoke was <a href="https://www.newspapers.com/image/492484602/">less harmful</a> than industrial smoke. We now know that forest smoke poses <a href="https://doi.org/10.1016/j.envres.2014.10.015">significant health risks</a> on par or <a href="https://doi.org/10.1038/s41467-021-21708-0">worse than those of industrial smoke</a>. Wildfire services, staffed largely by foresters and ecologists, are ill-equipped to make these kinds of public health decisions.</p>
<figure class="align-center ">
<img alt="Short animation of satellite imagery of smoke and wildfires generating lightning." src="https://images.theconversation.com/files/416803/original/file-20210818-27-otgdx5.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416803/original/file-20210818-27-otgdx5.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416803/original/file-20210818-27-otgdx5.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416803/original/file-20210818-27-otgdx5.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416803/original/file-20210818-27-otgdx5.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416803/original/file-20210818-27-otgdx5.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416803/original/file-20210818-27-otgdx5.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Raging wildfires spark lightning over British Columbia, in July 2021.</span>
<span class="attribution"><span class="source">(NOAA)</span></span>
</figcaption>
</figure>
<p>Climate change has made the decision to use prescribed fire more difficult. Although cultural or Indigenous burning promise a more holistic and inclusive approach to restoring fire to the land, colonial governments must avoid unloading the litigation and health risks of prescribed fire onto Indigenous communities, which already experience disproportionate impacts from wildfire and smoke.</p>
<p>Smoke seasons are not new, although climate change has exacerbated their scale and intensity. In planning for a smoky future, history shows how our responses to fire and smoke are cultural. Solutions like prescribed burning must take our historic relationship with fire and smoke into account.</p><img src="https://counter.theconversation.com/content/166326/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mica Jorgenson receives funding from the European Commision's Marie Skłodowska-Curie Actions. </span></em></p>Smoke has long cast shadows across the skies in the northern hemisphere. Our aversion to smoke has influenced the way we’re willing to deal with the rising risk of wildfires.Mica Jorgenson, Marie Skłodowska-Curie Postdoctoral Fellow, Faculty of Educational Sciences and Humanities, University of StavangerLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1650522021-08-02T14:03:20Z2021-08-02T14:03:20ZUp in smoke: How wildfires are tainting grapes and threatening the wine industry<figure><img src="https://images.theconversation.com/files/413826/original/file-20210729-19-1l1jb59.jpg?ixlib=rb-1.1.0&rect=135%2C298%2C5903%2C3675&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Smoke from the wildfires taints wine grapes, giving wine an ashy taste. </span> <span class="attribution"><span class="source">(AP Photo/Noah Berger) </span></span></figcaption></figure><iframe style="width: 100%; height: 175px; border: none; position: relative; z-index: 1;" allowtransparency="" src="https://narrations.ad-auris.com/widget/the-conversation-canada/up-in-smoke--how-wildfires-are-tainting-grapes-and-threatening-the-wine-industry" width="100%" height="400"></iframe>
<p>Fires can destroy vines and other <a href="https://www.winespectator.com/articles/the-impact-of-2020-s-wildfires-063021">vineyard infrastructure</a>, such as the vine posts or irrigation systems, but even distant fires pose a risk to wine grapes, due to a phenomenon known as smoke taint. Smoke taint refers to the undesirable ashy, smoky aroma of wines produced from grapes <a href="https://www.wineaustralia.com/getmedia/be15194e-0e9f-466e-bc7e-2171d635ed18/Final-Report-RD-05-02-3">exposed to wildfire smoke while ripening</a>.</p>
<p><a href="http://bcfireinfo.for.gov.bc.ca/hprScripts/WildfireNews/Statistics.asp">British Columbia has already surpassed</a> the <a href="https://www2.gov.bc.ca/gov/content/safety/wildfire-status/about-bcws/wildfire-statistics/wildfire-averages">10-year average</a> for number of forest fires and total hectares burned. Many of these fires are near the Okanagan Valley, an important Canadian wine-producing region. </p>
<p>As wildfires continue to edge closer to towns and agricultural areas, grape producers and wine makers in the Okanagan must once again deal with this increasingly frequent threat.</p>
<p>As an analytical chemist, I have been studying how wildfire smoke leaves a chemical signature in grapes, and researching ways in which we can prevent smoke taint from affecting wine produced in areas subject to these forest fires.</p>
<h2>Smoke taint: A stealthy threat</h2>
<p>Many may have noticed how the aroma of wood smoke, say from a camp fire, permeates clothing or hair, or how smoking a salmon imparts a delightful aroma to the meat. Smoke does not taint wines in the same way. </p>
<p>Wine grapes readily absorb the compounds responsible for smoky aromas, but once inside the grape, they are almost immediately transformed by enzymes into forms that <a href="https://doi.org/10.1021/jf800927e">cannot be perceived by smell or taste</a>. The problem is, the yeasts used for wine fermentation are able to regenerate the original smoky aromas. </p>
<p>Smoke poses a massive threat to B.C.’s wine industry. Most tainted wines smell bad and are unsellable. What’s worse is that these horrid odours usually remain undetected until after wineries have invested money and effort to harvest and ferment tonnes of grapes that may smell perfectly fine. </p>
<figure class="align-center ">
<img alt="Unsold barrels of wine filled with smoke-tainted wine." src="https://images.theconversation.com/files/413803/original/file-20210729-23-7lxloj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/413803/original/file-20210729-23-7lxloj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413803/original/file-20210729-23-7lxloj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413803/original/file-20210729-23-7lxloj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413803/original/file-20210729-23-7lxloj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413803/original/file-20210729-23-7lxloj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413803/original/file-20210729-23-7lxloj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Chardonnay wine barrels lay stocked at Willamette Valley Vineyards in Turner, Ore., after a California winemaker cancelled the contract due to wildfire smoke-tainted wine, in 2019.</span>
<span class="attribution"><span class="source">(AP Photo/Andrew Selsky)</span></span>
</figcaption>
</figure>
<p>The <a href="https://www.winespectator.com/articles/how-did-2020-s-wildfires-impact-california-wine">economic impact of smoke taint is hard to pin down</a> exactly, but it may be severe. For example, the Australian wine industry has recorded losses of up to <a href="https://doi.org/10.3390/beverages7010007">300 million Australian dollars</a> (the equivalent of C$276 million) due to bushfire smoke. In B.C., <a href="https://www.vivino.com/CA/en/fairview-cellars-fume-franc/w/5724681">while some</a> <a href="https://www.marquis-wines.com/the-hatch-2015-the-smokeshow-750ml/">smoke-tainted wines</a> may be sold as novelty items, the vast majority of it is simply undrinkable and must be thrown away. </p>
<h2>The chemistry of smoke taint</h2>
<p>The aroma of smoke is due in large part to a class of compounds known as volatile phenols. Volatile phenols readily evaporate at reasonably low temperatures, meaning they can be easily smelled. Some volatile phenols are so pungent, they can be detected by smell at concentrations in the <a href="https://doi.org/10.1021/jf2040548">low part-per-billion range</a>, which is roughly equivalent to mixing a teaspoon into an Olympic-sized swimming pool. </p>
<p>When volatile phenols enter either ripening grapes or their leaves, they are almost immediately detoxified through a process is generally known as <a href="https://doi.org/10.1021/jf103045t">glycosylation</a>, where volatile phenols are chemically linked to simple carbohydrate molecules like glucose. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Ash-covered grapes on the vine." src="https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413824/original/file-20210729-27-7c85nr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ash-covered grapes hang in a vineyard that was blanketed by smoke from wildfires in California.</span>
<span class="attribution"><span class="source">(AP Photo/Eric Risberg)</span></span>
</figcaption>
</figure>
<p>The volatile phenolic-glycosides produced in this process are not volatile, and lack an aroma. Some evidence shows that they are metabolized by <a href="https://doi.org/10.1021/jf405327s">bacteria in people’s mouths</a>, contributing to the perception of smoke taint up the back of the throat or mouth that steadily begins to intensify after a second or third sip of wine. </p>
<p>But the really big problem occurs when the yeast used to ferment the grapes <a href="https://doi.org/10.1111/j.1755-0238.2011.00128.x">break down the volatile phenolic-glycosides</a>. This regenerates smoky aromas in grapes that smelled perfectly fine. Interestingly, grapevine smoke exposure does not always lead to a tainted wine. Sometimes desirable levels of volatile phenols are leached into wines aged in <a href="https://doi.org/10.1021/jf035380x">oak barrels</a>. My colleagues and I have used sensitive analytical instruments to unravel these chemical mysteries. </p>
<h2>Can smoke taint be detected before grapes are harvested?</h2>
<p>Since 2015, students in my laboratory at the University of British Columbia’s Okanagan campus, in Kelowna, have been spearheading Canadian research on smoke taint. </p>
<p>Prior to this, the bulk of the research on smoke taint had been performed by Australian researchers. While Australia, like B.C., faces frequent wildfires, we reasoned that the differences in fuel sources, which would influence the types of specific volatile phenols present in smoke, and grape growing conditions would mean that chemical evidence of smoke taint in wine grapes would be unique for each region. </p>
<p>We devised a method to carefully <a href="https://doi.org/10.1021/acs.jafc.7b04946">simulate the effects a forest fire on B.C. vineyards</a>, using ponderosa pine needles, bark and local soil organic matter as our fuel source.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A custom-built smoking tent" src="https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413389/original/file-20210727-17-1con7jz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A custom-built smoking tent used to simulate the effects of forest fire smoke on wine grapes.</span>
<span class="attribution"><span class="source">(Matthew Noestheden)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We reasoned that by boiling grape juice in hydrochloric acid and chemically <a href="https://doi.org/10.1021/acs.jafc.7b03225">mimicking the yeast-induced transformations</a> of volatile phenolic-glycosides that occur during wine-making, we would be able to rapidly predict the concentration levels of volatile phenols after fermentation.</p>
<p>Our research showed that smoke-derived volatile phenols enter grapes and are transformed into non-volatile forms in under one hour. We know that these smoke-derived volatile phenols are actually transformed by grapes since they are detectable only after fermentation or boiling in acid. But, interestingly, they are not detectable <a href="https://doi.org/10.1016/j.foodchem.2018.03.097">solely as glycosides</a>. </p>
<p>Identifying how grapes chemically trap volatile phenols will help winemakers devise methods to remove them from grape juice or wine. This identification is also important because yeasts are <a href="https://doi.org/10.3390/molecules26154519">able to release</a> the free, smelly volatile phenols from these still unidentified forms. </p>
<h2>An ounce of prevention</h2>
<p>While efforts to identify how grapes chemically alter volatile phenols are ongoing, we have begun to use our tools and methods to focus on preventing smoke taint directly in the vineyard. </p>
<p>A <a href="https://doi.org/10.1021/acs.jafc.9b05859">preliminary screening</a> of three approved agricultural sprays revealed one product, intended for use on cherries, significantly reduced concentrations of volatile phenols in smoke-exposed grapes at harvest. But, after <a href="https://doi.org/10.3390/molecules26144311">a follow-up study</a> at three Okanagan vineyards failed to replicate these effects, our search continues.</p>
<figure class="align-center ">
<img alt="Testing of protecting sprays on grapes." src="https://images.theconversation.com/files/413379/original/file-20210727-24-9lgkb5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/413379/original/file-20210727-24-9lgkb5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413379/original/file-20210727-24-9lgkb5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413379/original/file-20210727-24-9lgkb5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413379/original/file-20210727-24-9lgkb5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413379/original/file-20210727-24-9lgkb5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413379/original/file-20210727-24-9lgkb5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wesley Zandberg and research student James Favell test potential protective sprays on table grapes outside their lab on UBC’s Okanagan campus.</span>
<span class="attribution"><span class="source">(Alexander Garner)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We have discovered, however, that red table grapes, available year-round in Canadian grocery stores, mimic the transformations of volatile phenols observed in on-the-vine wine grapes. This discovery means that we will be able to perform initial screens of dozens of variables and products in the lab, unconstrained by the Canadian grape-growing season. </p>
<p>In the meantime, Okanagan vineyards and wineries have to carefully evaluate their crops, monitoring for volatile phenols, sugar-coated or otherwise.</p><img src="https://counter.theconversation.com/content/165052/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wesley Zandberg receives funding from the Natural Sciences and Engingeering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI), the BC Wine Grape Council (BCWGC), the Canadian Glycomics Network, (Collaborative Team Grant) and The University of British Columbia (in the form of an Eminence Fund Grant). He has been financially supported by MITACS, in partnership with Supra Research and Development, a Kelowna-based analysis company that now offers smoke-taint tests for local and international wineries. </span></em></p>As wildfires continue to edge closer to towns and agricultural areas, grape producers and wine-makers in the Okanagan must once again deal with this increasingly frequent threat of smoke taint.Wesley Zandberg, Assistant Professor of Chemistry, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.