tag:theconversation.com,2011:/us/topics/mould-2612/articlesMould – The Conversation2024-03-18T13:44:28Ztag:theconversation.com,2011:article/2253962024-03-18T13:44:28Z2024-03-18T13:44:28ZAwaab’s law is a start but England needs whole new approach to ensure healthy homes for all<figure><img src="https://images.theconversation.com/files/580958/original/file-20240311-28-3bfgij.jpg?ixlib=rb-1.1.0&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/cullum-welch-house-part-golden-lane-1018003162">I Wei Huang | Shutterstock</a></span></figcaption></figure><p>In 2020 a coroner’s court in Rochdale found that <a href="https://theconversation.com/the-disturbing-parallels-between-awaab-ishaks-death-in-rochdale-and-the-grenfell-tower-disaster-195077">two-year-old Awaab Ishak</a> had died as a result of living in a mould-infested home. <a href="https://www.gov.uk/government/news/rsh-sets-new-standards-to-drive-improvements-in-social-housing">New housing standards</a>, devised as part of the social housing regulation bill in response to this tragedy, are now set to come into force in England. </p>
<p>From April 1 2024, all social housing providers in England will have to ensure their tenants’ safety by keeping apprised of the conditions of the homes they let and the needs of the people they house. They will have to listen to complaints and respond within strict time frames, particularly, under the section dubbed “<a href="https://bills.parliament.uk/bills/3177">Awaab’s law</a>”, to problems of mould and damp.</p>
<p>This will improve the lives of thousands living in social housing. However, like many reactive policies, it only addresses one part of a much wider problem. Elsewhere in the housing and planning system, the government is <a href="https://www.gov.uk/government/news/new-laws-to-speed-up-planning-build-homes-and-level-up">cutting regulations</a> to speed up house building, a process that the Labour party <a href="https://labour.org.uk/updates/press-releases/how-not-if-labour-will-jump-start-planning-to-build-1-5-million-homes-and-save-the-dream-of-homeownership/">wants to accelerate</a>. </p>
<p>Health is <a href="https://www.tandfonline.com/doi/full/10.1080/07352166.2023.2260029">often forgotten about</a> in housing policies. Amid the clamour for economic growth, house building targets and reducing bureaucracy, housing quality and tenant wellbeing take a back seat. Regulations and standards are often derided as unnecessary red tape, but they can perform a vital role in protecting health. For residents who live in poor-quality housing, the consequences can be severe. </p>
<p><a href="https://doi.org/10.1016/j.healthplace.2023.103023">Our research on health and housing</a> shows that these new regulations do not go far enough. The next UK government needs a comprehensive healthy-homes strategy, a move championed by the <a href="https://www.tcpa.org.uk/collection/campaign-for-healthy-homes/">Town and County Planning Association</a>. This would prevent tragedy, transform the lives of many tenants and have significant economic benefits.</p>
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<h2>Living with damp and mould</h2>
<p>The new social housing standards are part of a suite of reforms aiming to ensure that all tenants have decent, safe and secure homes. Awaab’s law sets requirements on <a href="https://www.gov.uk/government/news/government-to-deliver-awaabs-law">social landlords</a> to quickly investigate and repair hazardous conditions in the home such as damp and mould.</p>
<p>This is important. Around 1 million homes in the UK have a <a href="https://www.gov.uk/government/statistics/chapters-for-english-housing-survey-2022-to-2023-headline-report/chapter-4-dwelling-condition#damp">problem with damp</a>. Research <a href="https://commonslibrary.parliament.uk/research-briefings/cbp-9696/">shows</a> this can cause respiratory conditions – which can be critical – such as asthma and can damage mental health. In England, residents in an estimated <a href="https://files.bregroup.com/research/BRE_Report_the_cost_of_poor_housing_2021.pdf">75,000 homes experience conditions</a> so serious they are judged to pose an immediate risk to health and safety. </p>
<p>The UK government’s commitment to improving the quality of social housing is to be commended. However, it is striking that the government were only moved into action after a court inquest into the <a href="https://news.sky.com/story/awaab-ishak-toddlers-death-from-mould-triggers-review-of-landlord-guidance-12786323">tragic death</a> of a young child. </p>
<p>One obvious problem with this reactive mode is many important injustices and policy failings go unnoticed. It also means that when reforms do come, they only address one part of a much greater problem. </p>
<p>Damp and mould doesn’t just affect people in social housing. It’s actually a bigger problem in the private rented sector, where an estimated <a href="https://www.gov.uk/government/statistics/chapters-for-english-housing-survey-2022-to-2023-headline-report/chapter-4-dwelling-condition#damp">9% of homes</a> are affected by damp, compared to 5% in social housing. </p>
<p>The lack of security for many private sector tenants and the fear of eviction means they are also <a href="https://youtu.be/1FOc9F1IrOo">less likely to report</a> mould or damp. </p>
<h2>Making homes healthy</h2>
<p>Damp and mould are not the only problem. There are many other ways that poor housing quality can have important health consequences. Over 4,500 deaths in England in 2022 <a href="https://www.bbc.co.uk/news/uk-66890135">were linked to homes overheating</a>. Older people, young children and people with underlying health conditions are the most at risk from extreme heat and the <a href="https://www.resolutionfoundation.org/publications/its-getting-hot-in-here/">greatest burden</a> falls on poorer households. </p>
<p>Climate change will only intensify these problems. However, the UK is not well prepared. Research by the Committee on Climate Change has revealed that 55% of the housing stock in England is currently at risk of overheating. However, that number is likely to increase to <a href="https://www.theccc.org.uk/publication/addressing-overheating-risk-in-existing-uk-homes-arup/">90% of homes</a> with a 2°C rise in temperatures, an estimate well within the range of likely scenarios. </p>
<p>Regulations <a href="https://www.gov.uk/government/publications/overheating-approved-document-o">introduced in 2021</a> to prevent overheating only affect new homes. They will not protect the majority who live in older properties. </p>
<p>If these problems are to be solved, a piecemeal approach that reacts to specific high-profile cases is insufficient. Instead, the UK needs a comprehensive <a href="https://www.tcpa.org.uk/collection/campaign-for-healthy-homes/">healthy homes strategy</a> that addresses not just damp and overheating, but also overcrowding, noise pollution and indoor air pollution, all of which have important health consequences. It must regulate not just the social housing sector, but also housebuilders and private landlords. </p>
<p>With the <a href="https://www.gov.uk/government/publications/statement-of-levelling-up-missions/statement-of-levelling-up-missions#mission-7-health">Conservatives’</a> “mission to level up life expectancy” and <a href="https://labour.org.uk/wp-content/uploads/2023/05/Mission-Public-Services.pdf">Labour’s</a> “prevention first revolution”, both parties have ambitious targets on health. But neither plan will succeed without facing up to the shocking health consequences of squalid housing in the UK.</p><img src="https://counter.theconversation.com/content/225396/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research comes from the TRUUD project, a research programme based at the University of Bristol, that aims to reduce non-communicable disease (such as cancers, diabetes, obesity, mental ill-health and respiratory illness) and health inequalities linked to the quality of urban planning and development for use in discussions with government and the developer industry. The TRUUD research project (<a href="https://truud.ac.uk/">https://truud.ac.uk/</a>) is funded by the the UK Prevention Research Partnership (<a href="https://ukprp.org/">https://ukprp.org/</a>).</span></em></p>To truly make UK housing safe and healthful for residents, the government needs a comprehensive strategy.Geoff Bates, Lecturer in Social Policy, Research Fellow, University of BathJack Newman, Research Fellow, School for Policy Studies, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2151462023-12-24T20:54:15Z2023-12-24T20:54:15ZWhat if I discover mould after I move into a rental property? What are my rights?<figure><img src="https://images.theconversation.com/files/553157/original/file-20231011-21-rq753i.jpg?ixlib=rb-1.1.0&rect=0%2C59%2C4994%2C3259&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>A startling number of Australian rental homes come with an unwanted housemate: mould.</p>
<p>If you discover mould in a rented home, who is responsible and what can you do if the landlord seems unwilling to fix it?</p>
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<em>
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Read more:
<a href="https://theconversation.com/climate-related-disasters-leave-behind-trauma-and-worse-mental-health-housing-uncertainty-is-a-major-reason-why-206861">Climate-related disasters leave behind trauma and worse mental health. Housing uncertainty is a major reason why</a>
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<h2>Find the cause</h2>
<p>The landlord is responsible if the mould is caused by the structural condition of the property. This can include things like leaking pipes, gutters, roofs or windows. </p>
<p>Tenants are responsible for mould remediation if the way they occupy a home has promoted mould growth. For example, if they have not been using exhaust fans in bathrooms, have been failing to ventilate their home or have been storing wet clothes in a cupboard.</p>
<p>This means establishing the cause of the mould is crucial to working out who’s responsible for repairs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman looks at mould in a house." src="https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553158/original/file-20231011-29-newuk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Establishing the cause of the mould is crucial.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>Why are so many rentals mouldy?</h2>
<p>Australia has a rental home mould problem chiefly because much of our housing hasn’t been built to suit our climate. Houses tend not to be built with sufficient consideration of:</p>
<ul>
<li><p>efficient energy consumption to regulate indoor temperature</p></li>
<li><p>the orientation of homes</p></li>
<li><p>the use of double glazing and insulation to regulate temperature and humidity.</p></li>
</ul>
<p>It is estimated that nearly 17% of privately rented homes and 22% of social housing dwelling require <a href="https://www.abs.gov.au/statistics/people/housing/housing-mobility-and-conditions/2019-20">major repairs</a>. This includes structural defects, such as large cracks in walls or leaking gutters, that can generate mould growth. </p>
<p>Tenant representatives have said in the past there is also a problem of weak enforcement of laws concerning the <a href="https://www.ahuri.edu.au/sites/default/files/documents/2022-11/AHURI-Final-Report-391-Regulation-of-residential-tenancies-and-impacts-on-investment.pdf">condition of rental homes</a>. </p>
<h2>4 ways to cut mould risk</h2>
<p>To reduce your mould risk, you need to manage indoor moisture and temperature. Try to:</p>
<ul>
<li><p>keep the home well ventilated</p></li>
<li><p>open windows and use exhaust fans in the bathroom and kitchen</p></li>
<li><p>in humid climates, use air conditioning or a dehumidifier</p></li>
<li><p>in cold climate, use a dehumidifier (desiccant dehumidifiers might more appropriate in very cold places)</p></li>
<li><p>reduce moisture in the home by wiping up spills and condensation on surfaces</p></li>
<li><p>dry washing outside</p></li>
<li><p>if buying a dryer, opt for a condensing dryer instead of a conventional dryer (condensing driers put out much less vapour)</p></li>
<li><p>report any structural issues (such as leaking pipes or windows that don’t close properly) to the agent or landlord as soon as you notice them. </p></li>
</ul>
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<a href="https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Washing and clothing dries on a rack indoors." src="https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553160/original/file-20231011-17-d968r3.jpg?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">Don’t dry your washing inside.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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</figure>
<h2>Rental minimum standards differ by state or territory</h2>
<p>In New South Wales, adequate ventilation is one of the <a href="https://www.fairtrading.nsw.gov.au/housing-and-property/renting/new-residential-tenancy-laws">minimum standards</a> properties must meet to be considered fit to live in.</p>
<p>If the rental provider has been notified about mould problems in the house but has failed to act, you might consider getting advice from the <a href="https://www.tenants.org.au/?gclid=CjwKCAiAjfyqBhAsEiwA-UdzJEj1YE27QhWKv2W5hPiiFTXMeX5Yqe61X4WlsHwRcq5kh5qDnU-MEBoC2LgQAvD_BwE">Tenants’ Union of NSW</a>. </p>
<p>Its <a href="https://www.tenants.org.au/factsheet-24-mould">fact sheet on mould</a> also explains what to do if you’d like to contact the <a href="https://www.ncat.nsw.gov.au">NSW Civil and Administrative Tribunal</a> to apply for repairs, rent reduction or compensation. </p>
<p>In Victoria, <a href="https://www.consumer.vic.gov.au/housing/renting/repairs-alterations-safety-and-pets/minimum-standards/minimum-standards-for-rental-properties">rental minimum standards</a> say “all rooms must be free from mould and damp caused by or related to the building structure.”</p>
<p>The <a href="https://tenantsvic.org.au/advice/common-problems/mould-and-damp/">Tenants Victoria</a> website has information on how to ask a landlord to fix a mould problem or structural problems leading to mould and how to apply to the <a href="https://www.vcat.vic.gov.au">Victorian Civil and Administrative Tribunal</a> if the landlord fails to act.</p>
<p>In Queensland, it depends on when you signed the lease. If you signed after September 1 this year (after new <a href="https://www.housing.qld.gov.au/about/initiatives/rental-law-reform">standards</a> were introduced) tenants should notify the landlords of <a href="https://www.rta.qld.gov.au/during-a-tenancy/maintenance-and-repairs/mould">mould as soon as they discover it</a>.</p>
<p>If mould is a result of problems with the property and the landlord doesn’t undertake repairs, tenants can contact the <a href="https://www.qcat.qld.gov.au">Queensland Civil and Administrative Tribunal</a>. </p>
<p>The guidelines in <a href="https://www.legislation.wa.gov.au/legislation/statutes.nsf/main_mrtitle_821_homepage.html">Western Australia</a> say the landlord must ensure the premises is “in a reasonable state of cleanliness and a reasonable state of repair […] and must conduct any repairs within a reasonable period after the need for the repair arises.” And in <a href="https://www.commerce.wa.gov.au/publications/maintenance-your-rental-property-who-responsible-landlord-bulletin-issue-12-september">Western Australia</a>, mould caused by faults in gutters or other fixtures is the responsibility of the rental provider. Further information on <a href="https://www.commerce.wa.gov.au/consumer-protection/resolving-rental-property-issues">what to do</a> if a dispute over the premises can’t be resolved amicably is available on the state government website.</p>
<p>In <a href="https://www.housingsafetyauthority.sa.gov.au/minimum-housing-standards/whole-property">South Australia</a> rental properties must be “reasonably free from mould or other irritants [and] reasonably free from the adverse effects of moisture or damp.” If a landlord refuses to fix something after being asked, the tenant can <a href="https://www.sa.gov.au/topics/housing/renting-and-letting/renting-privately/during-a-tenancy/Repairs-and-maintenance">apply to the South Australian Civil and Administrative Tribunal</a>.</p>
<p>In <a href="https://www.cbos.tas.gov.au/topics/housing/renting/rental-maintenance-repairs-changes/requesting-repairs">Tasmania</a>, rental properties must be clean and in good repair when leased out. <a href="https://www.cbos.tas.gov.au/topics/housing/renting/beginning-tenancy/minimum-standards/types">According to</a> the Tasmanian government website on the issue, </p>
<blockquote>
<p>‘Clean’ includes having no […] serious mould/rising damp issues.</p>
</blockquote>
<p>If the tenant requests repairs and the landlord doesn’t act, the tenant can lodge a repair order with the <a href="https://www.cbos.tas.gov.au/topics/housing/renting/rental-maintenance-repairs-changes/requesting-repairs">Commisioner’s office</a>. </p>
<p>In the Australian Capital Territory, the Tenants’ Union ACT has guidance on what to do if you discover <a href="https://www.tenantsact.org.au/what-can-i-do-about-mould/">mould</a> in a property you rent.</p>
<p>In the Northern Territory, tenants may wish to seek advice from the <a href="https://www.dcls.org.au/tenants-advice/">Tenants’ Advice Service</a> if there is a mould problem in a property they rent.</p>
<h2>What policy change could help?</h2>
<p>If the cause of indoor mould is related to the design and construction of the house, rental providers should act. But tenants may not have the information they need to determine and substantiate this claim and can’t do much to get rental providers to act on mould if it’s not clear what’s causing it. Also, renters often worry asking for repairs could lead to a rent increase or eviction.</p>
<p>Solutions include strengthening tenants rights to compel landlords to investigate the cause of mould in a house (given that knowing the cause is essential to assign responsibility for repairs). There should also be more stringent enforcement of current minimum standards relating to mould in rental properties.</p>
<p>Given the scale of problems like mould in Australian homes, policymakers may wish to consider whether a parliamentary inquiry on home environments and health is needed. </p>
<p>This would give Australians a chance to speak about their experiences – something that could help policy makers improve regulation in the rental sector. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sudden-mould-outbreak-after-all-this-rain-youre-not-alone-but-you-are-at-risk-177820">Sudden mould outbreak after all this rain? You’re not alone – but you are at risk</a>
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<img src="https://counter.theconversation.com/content/215146/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Bentley receives funding from the National Health and Medical Research Council and the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Tim Law is the Technical Lead for Building Sciences at Restoration Industry Consultants (RIC). He has received funding from the National Health and Medical Research Council, the Australian Building Codes Board, the Victorian Building Authority, Consumer Building and Occupation Services (Tasmania) and Commercialisation Australia.</span></em></p>If the cause of the mould is related to the design and construction of the house, rental providers should act.Rebecca Bentley, Professor of Social Epidemiology and Director of the Centre of Research Excellence in Healthy Housing at the Melbourne School of Population and Global Health, The University of MelbourneTim Law, Adjunct lecturer, Victoria UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2184072023-12-05T12:39:03Z2023-12-05T12:39:03ZChristmas tree syndrome: why the festive evergreen can make your nose run – and what you can do about it<figure><img src="https://images.theconversation.com/files/563330/original/file-20231204-29-cia24o.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5760%2C3819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">These health issues are trigged by the allergens that normally reside in live Christmas trees.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/ruined-christmas-holidays-young-handsome-man-2221562955">voronaman/ Shutterstock</a></span></figcaption></figure><p>Decorating the Christmas tree is a beloved tradition for many of us during the festive season. While some people prefer using and reusing an artificial tree as an environmentally friendly way to enjoy the holiday spirit, others hunt instead for the perfect real tree to adorn with ornaments and cluster presents around.</p>
<p>But some people who decide to get a real tree may find that after it has been decorated they begin to experience cold-like symptoms. While many may simply chalk these symptoms up to having caught a cold – or even COVID – the culprit may actually be a little-known condition called <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">Christmas tree syndrome</a>. </p>
<p>Christmas tree syndrome encompasses a spectrum of health issues triggered by exposure to the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">allergens residing on live Christmas trees</a>. For those who are sensitive to allergens, prolonged exposure to live Christmas trees can lead to <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780128045435000075">respiratory</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930903/">skin health issues</a>.</p>
<p>The <a href="https://www.thermofisher.com/allergy/gb/en/living-with-allergies/understanding-allergies/is-christmas-tree-allergy-making-you-sick.html">main symptoms</a> of Christmas tree syndrome include a stuffy or runny nose, sneezing, irritated eyes, coughing, wheezing and itchy throat. Asthma symptoms may also worsen. <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0105-1873.2005.00495.x">Skin-related symptoms</a> may include redness, swelling, and itching.</p>
<p>This phenomenon happens thanks to the ecology of live trees, which carry microscopic entities – including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">pollen and fungi</a>. Pollen, a notorious outdoor allergen, may hitch a ride into our homes, while fungi find a cosy haven in cold, damp Christmas tree farms and garden centres.</p>
<p>Live Christmas trees can also carry mould. Notably, a single Christmas tree can host more than <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext">50 species of mould</a>, creating a habitat for these tiny yet potentially troublesome organisms. Many of the mould varieties found on trees are those <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext">most likely to trigger allergies</a>, including <em>Aspergillus</em>, <em>Penicillium</em>, and <em>Cladosporium</em>.</p>
<p>Researchers have also <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext#back-bib3">closely measured mould counts</a> in rooms containing live Christmas trees. During the first three days the tree is indoors, mould spore counts measure about 800 spores per cubic meter of air. On the fourth day, however, spore counts begin rising – eventually reaching 5,000 spores per cubic meter within two weeks.</p>
<p>Mould grows best in <a href="https://health.uconn.edu/occupational-environmental/wp-content/uploads/sites/25/2015/12/mold_guide.pdf">warm, wet and humid conditions</a>. So when the tree is brought indoors, the warmer climate <a href="https://medcraveonline.com/MOJI/MOJI-02-00045.pdf">significantly increases</a> mould production. </p>
<p>Pine pollen is not a major issue for allergy-sufferers when it comes to Christmas trees. But Christmas trees can come into contact with <a href="https://www.sciencedirect.com/science/article/abs/pii/S0021870730901050">other known allergens</a> while they’re growing, which can then be carried into the house. For example, grass pollen can stick to the sap in a Christmas tree during the spring. Then, when the tree is harvested and brought indoors, the sap dries out, and the trapped pollen particles are released into the air.</p>
<h2>Managing symptoms</h2>
<p>Certain people are at higher risk of experiencing Christmas tree syndrome. People with asthma or chronic obstructive pulmonary syndrome (COPD) may be more sensitive to allergens – and these allergens may also exacerbate symptoms such as coughing and wheezing.</p>
<p>People who suffer from allergies are also at greater risk – with research showing <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">7% of allergy-sufferers</a> experienced a spike in symptoms when they had a Christmas tree in their home. People with skin issues (such as contact dermatitis and itching) may also find that their symptoms worsen around fresh Christmas trees.</p>
<p>Timely recognition of symptoms is crucial to mitigate the impact of Christmas tree syndrome. So if you do suffer from allergies, here’s what you can do:</p>
<ol>
<li><p><strong>Select your tree carefully:</strong> Opt for varieties with lower allergenic potential. Fir trees, such as Douglas and Fraser, are known for producing fewer allergens compared to <a href="https://www.cabdirect.org/cabdirect/abstract/19700607118">spruce or pine</a>. </p></li>
<li><p><strong>Inspect your tree:</strong> Conduct a <a href="https://www.annallergy.org/article/S1081-1206(10)60670-9/fulltext">meticulous inspection for signs of fungi</a> before bringing the tree indoors. Focus on areas where moisture may accumulate, as damp conditions foster mould growth. The most common mould found on Christmas trees is <em>Aspergillus</em>, which will look black on the surface and usually white-ish or yellow underneath.</p></li>
<li><p><strong>Proper maintenence:</strong> <a href="https://www.entandallergyspecialists.com/uncategorized/can-christmas-trees-cause-allergy-symptoms/">Regularly water live trees</a> to prevent dehydration, as this can lead to mould growth. A well-hydrated tree is also less likely to harbour fungus. And since warm, moist environments increase mould growth, try to keep your house ventilated while it’s up. You might even consider using a dehumidifier to decrease moisture levels in your home.</p></li>
<li><p><strong>Minimise direct contact:</strong> Try to avoid too much direct contact when decorating the tree. Wearing gloves might be one may of reducing the risk of skin-related reactions.</p></li>
<li><p><strong>Go artificial:</strong> Consider artificial trees as a <a href="https://jamanetwork.com/journals/jama/article-abstract/662569">practical alternative</a>. These eliminate the risk of allergens and can be reused – reducing their environmental impact. </p></li>
</ol>
<p>Christmas tree syndrome can be a nuisance. But by considering the science and taking precautions, you can ensure an enjoyable and allergen-free festive season.</p><img src="https://counter.theconversation.com/content/218407/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 who usually suffer from allergies are most at risk.Samuel J. White, Senior Lecturer in Genetic Immunology, Nottingham Trent UniversityPhilippe B. Wilson, Professor of One Health, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2145712023-10-12T22:42:46Z2023-10-12T22:42:46ZHow do I know if a rental house is mouldy before I sign the lease? 12 things to check<figure><img src="https://images.theconversation.com/files/552431/original/file-20231006-25-vwdo4s.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5991%2C3988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Although most Australian states require homes be free of mould before they are rented out, seasoned renters know that’s not always the case. In fact, an alarming number of tenants report discovering mould after they’ve moved into a rental property.</p>
<p>But how can you tell? Based on our research and practical experience in the field, these are 12 questions worth considering before you sign a residential tenancy agreement.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/breaking-the-mould-why-rental-properties-are-more-likely-to-be-mouldy-and-whats-needed-to-stop-people-getting-sick-205472">Breaking the mould: why rental properties are more likely to be mouldy and what's needed to stop people getting sick</a>
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<h2>1. Have you asked the agent or landlord directly?</h2>
<p>Enquire upfront if there’s a history of mould in the property. Tell the agent or landlord if a household member has a chronic condition, such as asthma or an allergy, which could be exacerbated by mould exposure. It’s worth a shot.</p>
<h2>2. Can you see any mould?</h2>
<p>This sounds obvious but there’s an art to spotting the clues. Carpets retain a history of mould damage. If you’re allowed and without causing damage, carefully inspect under carpet in a corner in areas that could be prone to water coming in (such as near a bathroom, external wall or window). </p>
<p>Single-glazed windows often experience condensation, so check windows closely. Mould problems tend to show up most significantly on the south-facing side of the house, and can sometimes be spotted on fly screens or the exterior face of blinds and curtains.</p>
<h2>3. Are there damp smells in any room?</h2>
<p>Check if the agent or landlord has attempted to mask odours with air fresheners or incense.</p>
<h2>4. Has the place been recently repainted, re-carpeted or given a new floor?</h2>
<p>If so, ask the agent why and if any mould was found in the process.</p>
<h2>5. Do exhaust fans in the kitchen and bathroom work well?</h2>
<p>Make sure you understand where these fans release the ventilated air and moisture. You don’t want this to be the roof space (above the ceiling but below the roof) unless there are roof vents. </p>
<h2>6. Do the gutters leak?</h2>
<p>Look at the roof and try to find the valley gutters (these are the things between two planes of the roof and help direct rainwater down to the normal gutters). </p>
<p>If a downpipe is not located near a valley, there is a risk the gutter could <a href="https://www.youtube.com/watch?v=VDLlK0OWmqQ">overflow</a>. Look for water damage to roofs and eaves or sagging gutters.</p>
<h2>7. Are there water stains on the walls, floor, windows or ceiling?</h2>
<p>Check the frames and around the windows closely. Look under the kitchen and bathroom sinks for stains, blistering melamine or swelling particle board. </p>
<p>See if there’s swelling or peeling on the walls and skirting board on the shared wall between the shower and the adjoining room. Peeling or swelling could indicate a failed waterproofing membrane.</p>
<p>External walls in contact with the ground have the highest risk of rising damp, and south-facing walls tend to get the least sunlight. </p>
<h2>8. Is the property well ventilated?</h2>
<p>Are there fly screens so you can leave windows open? Is there anything making it hard to get fresh air? For example, do windows face a noisy main road? This means they are likely to remain closed.</p>
<h2>9. Is the home humid?</h2>
<p>Find out as much as you can about glazing, insulation and orientation. Is the home humid? You can find out with a thermo-hygrometer, a device often sold in hardware stores that reads temperature and relative humidity. In older houses with poor insulation, you can usually try to maintain the interior at 65% relative humidity with the help of a dehumidifier.</p>
<p>Are there any evaporative coolers in the home? These machines keep the room cool by evaporating water, but they add moisture to the air. Ask the agent if they can switch on any evaporative coolers to see if your sinuses feel irritated when you are near a vent. </p>
<h2>10. Are tiles cracked, lifted, uneven or loose?</h2>
<p>This can suggest water damage underneath, especially in the shower (or areas near the shower).</p>
<h2>11. Have you checked behind any furniture pushed up against walls?</h2>
<p>Having furniture pushed up like this can prevent walls from drying out. Look behind furniture for evidence of mould.</p>
<h2>12. Is there water pooling under the house?</h2>
<p>Are there garden beds or plants positioned right up against the walls? If the house is on a slope, does rain run off down the hill and pool under the house? See if you can go under the house to look and smell for mould.</p>
<img src="https://counter.theconversation.com/content/214571/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Bentley receives funding from the National Health and Medical Research Council and the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Tim Law is the Technical Lead for Building Sciences at Restoration Industry Consultants (RIC). He receives funding from the National Health and Medical Research Council, the Australian Building Codes Board, the Victorian Building Authority, Consumer Building and Occupation Services (Tasmania) and Commercialisation Australia.</span></em></p>Here are 12 questions worth considering before you sign a residential tenancy agreement.Rebecca Bentley, Professor of Social Epidemiology and Director of the Centre of Research Excellence in Healthy Housing at the Melbourne School of Population and Global Health, The University of MelbourneTim Law, Adjunct lecturer, Victoria UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2077372023-06-26T20:05:49Z2023-06-26T20:05:49ZWhat do the different colours of mould mean in my house?<figure><img src="https://images.theconversation.com/files/533888/original/file-20230626-29-3zt1z7.jpg?ixlib=rb-1.1.0&rect=23%2C62%2C4656%2C3205&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/jDRd_WHGFAI">Sandy Millar/Unsplash</a></span></figcaption></figure><p>You may be interested (or possibly horrified) to discover you ingest and inhale thousands of tiny life forms on a daily basis.</p>
<p>The air and surfaces around you are home to multitudes of <a href="https://www.sciencedirect.com/science/article/abs/pii/B978012394805200004X">bacteria, fungi, viruses</a>, mites, algae and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0043135400004206">protozoa</a>. Your skin isn’t much better, with a complex ecosystem of organisms called commensals which aren’t necessarily good or bad, but will shift in their composition depending on <a href="https://www.nature.com/articles/nature11053">where you live</a>, <a href="https://www.mdpi.com/2079-9284/6/1/2">the products you use</a> and <a href="https://elifesciences.org/articles/458">the pets you have</a>. </p>
<p>Most of these creatures are generally undetectable due to their microscopic size and low concentrations. But when they find a niche they can exploit, you might notice them by their smell, or the appearance of unwanted staining and colour changes. A lot of this fungal growth is what we call mould.</p>
<p>We’ve all been disappointed in ourselves at one time or another, lifting a neglected orange out of the fruit bowl to discover the bottom half is covered in a velvety blue-green growth.</p>
<p>But what do the myriad colours that appear on our stuff tell us about the world we try not to think about?</p>
<h2>Black</h2>
<p>Often black staining is quite a disturbing occurrence. The concept of toxic black mould is one many people have become aware of due to <a href="https://theconversation.com/fungi-after-the-floods-how-to-get-rid-of-mould-to-protect-your-health-111341">flood impacts</a>.</p>
<p>A quick online search will likely terrify you, but not all black discolouration is due to the same organisms, and almost none of it will outright cause you harm.</p>
<p><em>Stachybotrys</em> is the one known as toxic black mould. It often turns up on <a href="https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.99107s3505">building materials that have been wet for a long time</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A severely mouldy wall covered in grey and black blotches" src="https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=483&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=483&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=483&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Toxic black mould can develop in the home due to a flood or chronic damp conditions.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/water-damage-causing-mold-growth-on-547425403">Shutterstock</a></span>
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<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-does-household-mould-affect-your-health-48341">Health Check: how does household mould affect your health?</a>
</strong>
</em>
</p>
<hr>
<p>When the grout in your shower turns black though, that’s a different fungus called <em><a href="https://www.ajol.info/index.php/ajb/article/view/130453">Aureobasidium</a></em>. It’s slimy, sticky and somewhere between a filamentous mould, which grows threadlike roots through whatever it’s eating, and a yeast, which prefer a free-floating, single-celled style of life. </p>
<p>Bleaching will often kill <em>Aureobasidium</em>, but the dark pigmentation will likely hang around – harmlessly, but stubbornly.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up of white grout between grey tiles with black spots on it" src="https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&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 mould colonising the grout in your shower is unlikely to be toxic. In fact, you can kill it with bleach, but the harmless pigment may linger behind.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/black-green-mold-growing-on-shower-1999288574">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Blue</h2>
<p>That blue orange I mentioned before, you can thank <em>Penicillium</em> for that. The organism that <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168160512000852">gives us blue cheese</a> and the antibiotic penicillin is also responsible for producing a dense growth of mould that almost looks like smoke when disturbed, spreading millions of spores onto the rest of your fruit bowl.</p>
<p><em>Penicillium</em> is a big group with <a href="https://www.sciencedirect.com/science/article/pii/S0166061620300129">hundreds of species</a>, ranging from recognised pathogens to species yet to be named. However, the ones that turn up in our homes are generally the same “weed” species that simply cause food spoilage or grow in soil. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a bright orange with a fuzzy blue mould spot on it" src="https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.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">Mould growing in your fruit bowl is related to the one that gave us penicillin. The dusty appearance are spores waiting to be disturbed and spread all over your other fruit.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/moldy-orange-fruit-close-rotten-concept-2131666769">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Yellow and orange</h2>
<p>We often think of fungi as organisms that thrive in the dark, but that’s not always true. In fact, some need exposure to light – and ultraviolet (UV) light in particular – to complete their life cycle.</p>
<p>Many plant pathogens use UV light exposure as a trigger to produce their spores, and then protect their DNA by <a href="https://link.springer.com/article/10.1134/S0003683814020094">hiding it behind melanin-containing shells</a>.</p>
<p><em>Stemphylium</em> and <em>Epicoccum</em> turn up in our homes from time to time, often hitching a ride on natural fibres such as jute, hemp and hessian. They produce a spectrum of staining that can often turn damp items yellow, brown or orange. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A piece of wood laminate with yellow patches on it" src="https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?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">Yellow moulds can leave a stain behind even once the spores are gone.</span>
<span class="attribution"><span class="source">Michael Taylor</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Green</h2>
<p>We’re all fairly familiar with the green spots that turn up on mouldy bread, cake and other food items. Often we try to convince ourselves if we just cut off the bad bit, we can still salvage lunch.</p>
<p>Sadly that’s not the case, as the roots of the fungi – collectively called mycelium – spread through the food, digesting and collecting sufficient nutrients to pop out a series of tiny fruiting bodies which produce the coloured spores you see.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-is-it-safe-to-cut-mould-off-food-21382">Health Check: is it safe to cut mould off food?</a>
</strong>
</em>
</p>
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<p>The green tuft is often from a group of fungi called <em>Aspergillus</em>. Under the microscope they look rather like the puffy top of a dandelion gone to seed.</p>
<p>Like <em>Penicillium</em>, <em>Aspergillus</em> is another big fungal group with lots of species that turn up virtually in every environment. Some are <a href="https://academic.oup.com/mmy/article/43/Supplement_1/S87/1748298">heat tolerant</a>, some <a href="https://www.tandfonline.com/doi/full/10.1080/21553769.2015.1033653">love acid</a> and some will happily produce spores that <a href="https://www.sciencedirect.com/science/article/abs/pii/S1749461311000406">stay airborne for days to months at a time</a>.</p>
<p>In the green gang is also a fungus called <em>Trichoderma</em>, which is Latin for “hairy skin”. <em>Trichoderma</em> produces masses of forest-green, spherical spores which tend to grow on wet cardboard or dirty carpet. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A pile of green grains on a small round tray" src="https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.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">Trichoderma is present in all soils, and will grow fast if the conditions are right.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/trichoderma-biocontrol-agent-plant-disease-control-670125520">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Pink, purple and red</h2>
<p>There are plenty to speak of in this category. And there is also a common bacterium that makes the list.</p>
<p><em>Neurospora</em>, also known as the red bread mould, is one of the most studied fungi in scientific literature. It’s another common, non-hazardous one that has been used as <a href="https://bsapubs.onlinelibrary.wiley.com/doi/full/10.3732/ajb.1400377">a model organism</a> to observe fungal genetics, evolution and growth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A block of orange mouldy substance sitting on a banana leaf" src="https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.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">Red oncom, a traditional staple food in West Java, Indonesia, is made with <em>Neurospora</em>.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fresh-raw-red-oncom-vegetarian-food-396059380">Shutterstock</a></span>
</figcaption>
</figure>
<p><em>Fusarium</em> is less common indoors, being <a href="https://www.sciencedirect.com/science/article/pii/S0261219416302794">an important crop pathogen</a>, but will sometimes turn spoiled rice purple. It also occasionally turns up on wet cement sheet, causing splotchy violet patches. <em>Fusarium</em> makes large, sticky, moon-shaped spores that have evolved to spread by rain splashes and hang onto plants. However, it is fairly bad at getting airborne and so doesn’t tend to spread very far from where it’s growing. </p>
<p>Finally in this category, that pink scum that turns up around bathroom taps or in the shower? It’s actually a bacterium called <em>Serratia</em>. It will happily chew up the soap scum residue left over in bathrooms, and has been shown to <a href="https://journals.asm.org/doi/full/10.1128/AEM.02632-10">survive in liquid soaps and handwash</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of white tile grout covered in a pink translucent film" src="https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?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"></a>
<figcaption>
<span class="caption">Some of the pink stuff in your bathroom isn’t even mould – it’s bacteria.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/red-bacteria-serratia-marcescens-growing-on-1694681443">Shutterstock</a></span>
</figcaption>
</figure>
<h2>White</h2>
<p>When fungi were first being classified and were eventually given their own phylogenetic kingdom, there were lots of wonderful and not strictly categorical ways we tried to split them up. One of these was hyaline and non-hyaline, essentially referring to transparent and coloured, respectively.</p>
<p>One of the interesting non-pigmented moulds you may well catch sight of is a thing called <em>Isaria farinosa</em> (“farinosa” being Latin for “floury”). This fungus is a parasite of some moths and cicadas and is visible as brilliant white, <a href="https://www.tandfonline.com/doi/abs/10.1080/09583150802471812">tree-shaped growths on their unfortunate hosts</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dead bug on a green forest floor with white and yellow growths sticking out of it" src="https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?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 example of <em>Isaria farinosa</em> growing out of its host.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Isaria_farinosa_%28Holmsk.%29_Fr_448940.jpg">Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>So when you notice the world around you changing colour, you can marvel with your newfound knowledge at the microscopic wonders that live complex lives alongside yours. Then maybe clean it up, and give the fruit bowl a wash. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hidden-housemates-meet-the-moulds-growing-in-your-home-54743">Hidden housemates: meet the moulds growing in your home</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/207737/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Taylor consults for WSP Australia in the area of occupational hygiene, indoor environmental quality and hazardous materials. He has previously received grant funding from SafeWork SA to study fungi in indoor environments. </span></em></p>Usually, mould spores are invisible – but give them a niche to exploit and you’ll get all kinds of colours on the things in your home.Michael Taylor, Adjunct academic, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2054722023-05-15T20:06:27Z2023-05-15T20:06:27ZBreaking the mould: why rental properties are more likely to be mouldy and what’s needed to stop people getting sick<figure><img src="https://images.theconversation.com/files/525822/original/file-20230512-27-xb83ft.jpg?ixlib=rb-1.1.0&rect=168%2C19%2C2451%2C1445&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Daniel Mason</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Rental properties are more <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8835129/">likely be mouldy</a> than other homes. This is a concern as excessive mould growth is known to <a href="https://www.who.int/publications/i/item/9789289041683">harm human health</a>. </p>
<p>Once buildings are infested with mould, the difficult and costly issue of remediation arises. Landlords and tenants are caught in the middle of a tussle over who is responsible for fixing the problem. As one Melbourne renter and research participant told our colleague Maria Gatto, during a study validating mould reporting: </p>
<blockquote>
<p>The landlord came around [and] walked [into] every room where there’s black mould on the ceiling – like it’s freaking [something out of the TV series] Stranger Things – and she’s like, ‘Oh, a little bit of mould in winter, it’s very normal, it’s fine […] this happens every winter, it’s not a big deal’. </p>
</blockquote>
<p>Heading into winter, after <a href="https://theconversation.com/la-nina-3-years-in-a-row-a-climate-scientist-on-what-flood-weary-australians-can-expect-this-summer-190542">three consecutive La Niñas</a>, <a href="https://theconversation.com/sudden-mould-outbreak-after-all-this-rain-youre-not-alone-but-you-are-at-risk-177820">conditions are ripe</a> for a mega-mould season. Combining our expertise in health, law, building and construction, we examine the problem of mould in homes and offer guidance for both renters and landlords.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sudden-mould-outbreak-after-all-this-rain-youre-not-alone-but-you-are-at-risk-177820">Sudden mould outbreak after all this rain? You’re not alone – but you are at risk</a>
</strong>
</em>
</p>
<hr>
<h2>Ideal conditions for growth</h2>
<p>Mould is a <a href="https://www.cdc.gov/niosh/topics/indoorenv/whatismold.html">fungal growth</a> that reproduces via tiny airborne particles called spores. When these spores settle on moist, plant-based construction materials such as wood, wallpaper or plasterboard, they can form a new colony. </p>
<p>Growth is more likely when homes are cold, humid, lack air flow, or suffer from water damage. Outbreaks have been reported in flooded parts of southeastern Australia. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sD2Ij_QlzwA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Black mould an invisible threat growing behind walls of flood-affected homes (ABC News)</span></figcaption>
</figure>
<p>So why is the problem of household mould worse in rentals? <a href="https://www.ahuri.edu.au/research/final-reports/338">Weak regulation of tenancy legislation</a> is just one of many factors. Rental properties tend to be poorly maintained, with <a href="https://www.ahuri.edu.au/research/final-reports/338">structural problems</a> such as leaks. Given this, they can be expensive to heat. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart showing the percentage of homes with structural defects in each category" src="https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=422&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=422&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=422&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=531&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=531&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526246/original/file-20230515-19465-odirz2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=531&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Rental homes have more structural defects than owner-occupied homes.</span>
<span class="attribution"><a class="source" href="https://www.ahuri.edu.au/research/final-reports/338">Nicola Willand, using data from Moore et. al., (2020), Warm, cool and energy-affordable housing policy solutions for low-income renters, AHURI Final Report, vol. no. 338. Appendix 2</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>How mould makes people sick</h2>
<p>The <a href="https://www.who.int/publications/i/item/9789289041683">World Health Organization</a> recognises mould can be harmful. </p>
<p>A 2022 Asthma Australia <a href="https://asthma.org.au/what-we-do/advocacy/housing/">report</a> revealed people living in mouldy homes were more likely to have asthma and allergies. A systematic review of peer-reviewed research found <a href="https://erj.ersjournals.com/content/38/4/812">children living in mouldy homes</a> were more likely to experience asthma, wheeze and allergic irritation of the eyes, nose, throat and mouth (allergic rhinitis). </p>
<p>Living with mould is a source of stress. People worry about the consequences for their health and there is a growing body of evidence describing the <a href="https://jech.bmj.com/content/50/1/56">negative mental health effects</a> of mouldy, damp homes.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/thinking-of-buying-a-dehumidifier-advice-from-an-expert-on-mould-and-damp-178633">Thinking of buying a dehumidifier? Advice from an expert on mould and damp</a>
</strong>
</em>
</p>
<hr>
<h2>Problems with managing mould in the rental sector</h2>
<p>There is a gap between building and residential tenancies legislation. A building deemed to meet the minimum standards of the construction code with respect to mould may not meet the minimum standards for rental. That’s because there’s ambiguity in the <a href="https://ncc.abcb.gov.au/">National Construction Code</a> around “minimum standards of health”. </p>
<p>For example the Victorian <a href="https://www.legislation.vic.gov.au/in-force/acts/building-act-1993/136">Building Act 1993</a> contains some provisions for the relevant surveyor to serve a notice on the basis of a health circumstance affecting a user. However, there is no guidance on how to assess the health of the indoor environment, or to deliver a building direction that will address the root cause for mould. This varies by state and territory. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1559375910842667008"}"></div></p>
<p>Mould remediation can be costly. A <a href="https://www.vba.vic.gov.au/about/research/examining-indoor-mould-and-moisture-damage-in-victorian-residential-buildings">study</a> by Victoria University found half the defects causing mould were water-related. These were more expensive to fix than other problems, by an average of A$7,000. </p>
<p>Each winter, <a href="https://tenantsvic.org.au/advice/common-problems/mould-and-damp/">Tenants Victoria</a> deals with a spike in renters seeking legal help to resolve their mould problems. This led to the service launching an annual winter Mould Clinic in 2021. </p>
<p>Despite increased legal protections, renters are still struggling to get mould fixed. For these reasons, many renters find the legal process doesn’t offer a solution to their problem, and instead move to a new property, with all its attendant costs and stresses. Others can’t afford to leave, or live in social housing with limited transfer options. </p>
<h2>Charting mould in homes across Australia</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bar chart comparing the prevalence of mould in homes across Australian states and territories" src="https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525848/original/file-20230512-21-xb83ft.jpg?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"></a>
<figcaption>
<span class="caption">Mould is more prevalent in rentals compared to owner-occupied dwellings. Mould is most commonly reported in New South Wales. The difference between owners and renters is greatest in the ACT.</span>
<span class="attribution"><span class="source">Australian Housing Conditions Dataset 2022 doi:10.26193/SLCU9J</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Where does the responsibility lie?</h2>
<p>Tenancy legislation varies by state and territory. Renters should familiarise themselves with the regulations in their jurisdiction. </p>
<p>In Victoria, <a href="https://www.legislation.vic.gov.au/in-force/acts/residential-tenancies-act-1997/101">residential tenancies legislation</a> has set the criteria that “each room in the rented premises must be free from mould and damp caused by or related to the building structure”. Landlords now must disclose if they have treated mould in the past three years. </p>
<p>Similarly, <a href="https://www.rta.qld.gov.au/rental-law-changes">new legislation in Queensland</a> (coming into effect in September) states rental properties should be free from vermin, damp and mould where this is caused by issues with the structural soundness of the property.</p>
<p>In New South Wales, the landlord needs to <a href="https://www.fairtrading.nsw.gov.au/housing-and-property/renting/during-a-tenancy/health,-safety-and-security">disclose signs of mould</a> and dampness in the condition report (but not necessarily have fixed it). Mould is not mentioned in the <a href="https://www.legislation.act.gov.au/a/1997-84/">ACT residential tenancies legislation</a>. </p>
<p>For the most part, the responsibility for mould in rental properties lies with landlords if the cause is structural –- for example, if a broken or faulty window frame has let rainwater inside. </p>
<p>Requests for urgent repairs can be accompanied by an assessment report by an occupational hygienist, environmental health professional or expert from the local council. People with an existing health condition such as asthma can include a doctor’s report. </p>
<h2>What next?</h2>
<p>To achieve change across all relevant domains of regulation, construction, natural disaster response and government policy, we need a sustainable, broad healthy <a href="https://www.healthyhousing-cre.org">housing agenda in Australia</a>. We also need to consider options for immediate action. </p>
<p>As one Victorian renter noted: </p>
<blockquote>
<p>When we buy a car for the purpose of driving on the roads, we’re required to get a roadworthy certificate to make sure it’s safe, because of the risk to other people […] Ideally it would be great if there was [some] kind of ‘rentworthy’ certificate […] to demonstrate that the property has been inspected, to identify any structural issues that might affect the tenant’s health and wellbeing. And that that be available to tenants […] before they enter into a lease or before (the property is) even able to be advertised. </p>
</blockquote>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mould-and-damp-health-costs-are-about-3-times-those-of-sugary-drinks-we-need-a-healthy-housing-agenda-147743">Mould and damp health costs are about 3 times those of sugary drinks. We need a healthy housing agenda</a>
</strong>
</em>
</p>
<hr>
<p><em>For those in Melbourne, a <a href="https://www.eventbrite.com.au/e/617547921457">free Tenants Victoria event</a> on this topic will be held at RMIT University Storey Hall on Wednesday, May 17 at 1pm. It will be followed by a free pop-up legal clinic.</em></p>
<p><em>Quotes in this article were collected by Maria Gatto as part of her Masters of Public Health, conducted at the Melbourne School of Population and Global Health in 2022.</em></p><img src="https://counter.theconversation.com/content/205472/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Bentley receives funding from the National Health and Medical Research Council and the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Nicola Willand receives or has received funding for research from various organisations, including the Australian Research Council, the Victorian State Government, the Lord Mayor’s Charitable Foundation, the Australian Housing and Urban Research Institute, the Future Fuels Collaborative Research Centre and the Australian National Health and Medical Research Centre. She is affiliated with the Australian Institute of Architects. </span></em></p><p class="fine-print"><em><span>Tim Law receives or has received funding from the Victorian Building Authority, the National Health Medical and Research Council, the Australian Building Codes Board, Tasmania Consumer Building and Occupational Services, and Commercialisation Australia.</span></em></p>Mould is a health hazard and renters are most at risk. Here experts in health, law, building and construction examine the problem of mould in homes and offer guidance for both renters and landlords.Rebecca Bentley, Professor of Social Epidemiology and Director of the Centre of Research Excellence in Healthy Housing at the Melbourne School of Population and Global Health, The University of MelbourneNicola Willand, Senior Lecturer, School of Property, Construction and Project Management, RMIT UniversityTim Law, Adjunct lecturer, Victoria UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2002712023-02-26T23:55:22Z2023-02-26T23:55:22ZThis freaky slime mould from HBO’s The Last of Us isn’t a fungus at all – but it is a brainless predator<figure><img src="https://images.theconversation.com/files/512123/original/file-20230224-16-zaem1b.jpg?ixlib=rb-1.1.0&rect=0%2C38%2C2823%2C2074&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Slime mould navigating a food grid.</span> <span class="attribution"><span class="source">Chris R. Reid/Macquarie University</span>, <span class="license">Author provided</span></span></figcaption></figure><p>In HBO’s post-apocalyptic drama The Last of Us, human civilisation has fallen in the face of a fungal takeover triggered by climate change.</p>
<p>The show’s opening credits and creature designs are inspired by the slime mould <em>Physarum polycephalum</em>. But while the show’s “infected” (i.e. zombies) are meant to be victims of a fungal pandemic, slime moulds are not actually fungi at all.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/8SWhBsbxmpk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Opening credits for The Last of Us. HBO Max/YouTube.</span></figcaption>
</figure>
<p>They are in fact much more ancient, and less closely related to fungi than even we are. Since scientists first tried to classify slime moulds, they have been wrongly grouped with plants, animals, and in particular, fungi. </p>
<p>This is because they typically occur in the same ecosystems as fungi, and because they produce structures to help spread their spores, much like their fungal cousins do. </p>
<p>Molecular methods for grouping lifeforms by comparing their DNA have helped us better understand slime moulds’ distinct heritage. Yet their exact place on the tree of life is still unclear. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/before-the-last-of-us-i-was-part-of-an-international-team-to-chart-the-threat-of-killer-fungi-this-is-what-we-found-199593">Before The Last of Us, I was part of an international team to chart the threat of killer fungi. This is what we found</a>
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</em>
</p>
<hr>
<h2>A fierce predator</h2>
<p>Despite bearing a superficial similarity to fungi, there are many aspects of the slime mould’s biology that are strikingly unique. This yellow blob of goo may not look like much, but it is in fact a fierce predator of bacteria, yeasts and other microorganisms, including fungi. </p>
<p>Though they can grow quite large – up to several square metres across – each slime mould is a single cell, containing millions of nuclei and all the other complex machinery that lies inside cells like ours.</p>
<p>The slime mould’s “body” is a network of veins and tubes that can move at the rapid pace of up to five centimetres per hour to locate and capture their prey.</p>
<p>Inside the slime mould, a rich soup of cell components and food particles flows back and forth within the network. This flow transmits nutrients, chemical signals and information between different regions of the slime mould.</p>
<p>These rippling, sprawling movements are likely what makes slime mould so appealingly creepy to horror artists and filmmakers.</p>
<figure class="align-center ">
<img alt="A prosthetic humanoid corpse against a brick wall, with orange bracket fungi growing from the skin and network-like yellow material spreading out from the body onto the wall." src="https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=482&fit=crop&dpr=1 600w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=482&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=482&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=605&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In this behind the scenes shot, one of ‘the infected’ from HBO’s The Last of Us is plastered to the wall by what looks like giant slime moulds.</span>
<span class="attribution"><a class="source" href="https://www.instagram.com/p/CnfLqb9KGYL/">@barriegower/Instagram</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-last-of-us-fungal-infections-really-can-kill-and-theyre-getting-more-dangerous-198184">The Last of Us: fungal infections really can kill – and they’re getting more dangerous</a>
</strong>
</em>
</p>
<hr>
<h2>Zombie intelligence</h2>
<p>Slime mould physiology and anatomy is as alien as it is fascinating. But it’s their behaviour that separates them from their peers, and perhaps mirrors our own a little too closely for comfort. </p>
<p>Far from being simple cells moving blindly through the leaf litter, slime moulds can gather a huge amount of information from their environment, and use it to make smart decisions about where to move and look for food, much like the infected in The Last of Us, which operate as one large organism in search of prey. </p>
<p>So far, the slime mould has been shown to sense and move toward or away from <a href="https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-108-1-17">carbohydrates</a>, proteins, <a href="https://www.sciencedirect.com/science/article/pii/0014482778904615">amino acids</a>, <a href="https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-102-1-145">free nucleotides</a>, <a href="https://www.tandfonline.com/doi/full/10.4161/cib.28543">volatile organic chemicals</a>, <a href="https://www.sciencedirect.com/science/article/pii/0301462280870232">salts</a>, pH, light, humidity and <a href="https://europepmc.org/article/med/943401">temperature</a>, even sensing the direction of <a href="https://www.sciencedirect.com/science/article/pii/0309165187900142">gravity</a> and <a href="https://ieeexplore.ieee.org/abstract/document/6505318">magnetic fields</a>.</p>
<p>When a slime mould finds several food sources at the same time, it tries to cover each food with as much of itself as it can (to absorb it), without splitting into disconnected individuals. The most efficient way to do this is to have a single tube connecting the two foods along the shortest path between them. </p>
<p>Slime moulds have evolved over millions of years to become master network engineers. They are expert <a href="https://www.nature.com/articles/35035159">maze-solvers</a>, and researchers have begun to build computer algorithms for the design of <a href="https://www.science.org/doi/full/10.1126/science.1177894">human train and telecommunication networks based on slime mould approaches</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/HkM7FjmJ5dM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The yellow blob of goo is a single network (and single cell) of Physarum polycephalum exploring the surface of an agar plate in search of food. The footage is sped up significantly (around 20x). Chris R. Reid/New Jersey Institute of Technology.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-brainless-slime-mould-that-remembers-where-its-been-10015">The brainless slime mould that remembers where it's been</a>
</strong>
</em>
</p>
<hr>
<h2>No brain? No problem</h2>
<p>Slime moulds’ problem-solving abilities are all the more fascinating because the creature doesn’t have a brain or even a single neuron. Nevertheless, they show signs of memorisation and even learning – two things which traditionally were thought possible only in animals with brains.</p>
<p>As they move, slime moulds leave behind a trail of slime similar to mucous. This slime trail serves as an <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1215037109">externalised memory</a> of areas it has explored in the past, which is very useful for solving mazes.</p>
<p>They can distinguish between their own trails, their neighbours’, and those of <a href="https://academic.oup.com/beheco/article/24/4/812/220539">other slime mould species</a>. They also use food signals left behind in the trails to <a href="https://royalsocietypublishing.org/doi/full/10.1098/rstb.2019.0470">judge their own chances of finding food in an area</a>.</p>
<p><a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2016.0446">Researchers have also found</a> slime moulds can learn to ignore a substance they normally find repellent (such as quinine or caffeine) after prolonged exposure. Researchers call this basic form of learning “habituation”.</p>
<p>Amazingly, when a habituated slime mould fuses together with an untrained slime mould (oh yeah, they can do that), <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2016.2382">the learned behaviour is observed in the new combined individual</a>.</p>
<p>All this raises the (somewhat creepy) question: what other kinds of knowledge do slimy creatures pass between each other as they crawl beneath the forest floor?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/natures-traffic-engineers-have-come-up-with-many-simple-but-effective-solutions-94818">Nature's traffic engineers have come up with many simple but effective solutions</a>
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</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/200271/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris R. Reid receives funding from the Australian Research Council.</span></em></p>Slime moulds feature throughout HBO’s The Last of Us. While they aren’t a true fungus, they do have a lot in common with zombies.Chris R. Reid, ARC Future Fellow, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1888272022-08-18T05:01:04Z2022-08-18T05:01:04Z‘I’ve never actually met them’: what will motivate landlords to fix cold and costly homes for renters?<figure><img src="https://images.theconversation.com/files/479771/original/file-20220818-639-g1y3mc.jpg?ixlib=rb-1.1.0&rect=0%2C155%2C5184%2C3515&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Kindel Media/Pexels</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Cold weather and rising energy costs, combined with poor-quality housing, have left many renters struggling to keep warm this winter. The <a href="https://assets.nationbuilder.com/betterrenting/pages/345/attachments/original/1660523224/Cold_and_costly_-_Winter_Renter_Researchers.pdf?1660523224">Cold and Costly</a> report released this week by Better Renting shows how cold, mouldy homes and high energy bills take a toll on the physical and mental health of renters who live in homes that have often been likened to “glorified tents”. </p>
<p>Landlords are responsible for maintaining and improving rental properties. We interviewed landlords in Victoria about how they make decisions that affect the energy efficiency of their rental properties. Some might be surprised by what <a href="https://www.sciencedirect.com/science/article/abs/pii/S2214629622000408">our research</a> revealed: landlords who retrofit homes generally do it to improve renters’ comfort, rather than being motivated by increased rents.</p>
<p>However, a major issue is that many landlords who use property managers are unaware of tenants’ discomfort.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1557215422650273792"}"></div></p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/people-are-shivering-in-cold-and-mouldy-homes-in-a-country-that-pioneered-housing-comfort-research-how-did-that-happen-188809">People are shivering in cold and mouldy homes in a country that pioneered housing comfort research – how did that happen?</a>
</strong>
</em>
</p>
<hr>
<h2>Many rented homes are dangerously cold</h2>
<p>Renters are more likely than home owners to live in cold houses. The cold is typically due to substandard insulation and a lack of energy-saving features and solar panels to keep energy costs down. </p>
<p>The <a href="https://www.who.int/publications/i/item/WHO-CED-PHE-18.10">World Health Organisation recommends</a> that homes be kept at or above 18°C. By that standard, about <a href="https://www.nature.com/articles/s41597-022-01136-5">one in five renters</a> live in homes that are dangerously cold. <a href="https://theconversation.com/chilly-house-mouldy-rooms-heres-how-to-improve-low-income-renters-access-to-decent-housing-116749">Low-income renters</a> are especially likely to live in homes they can’t keep warm. </p>
<p>Cold homes contribute to respiratory illnesses and even deaths. In fact, cold plays a role in almost <a href="https://theconversation.com/forget-heatwaves-our-cold-houses-are-much-more-likely-to-kill-us-83030">7% of deaths</a> in Australia. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1535146920217575424"}"></div></p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/forget-heatwaves-our-cold-houses-are-much-more-likely-to-kill-us-83030">Forget heatwaves, our cold houses are much more likely to kill us</a>
</strong>
</em>
</p>
<hr>
<h2>Improving rented homes is landlords’ responsibility</h2>
<p>While there are some things renters can do to <a href="https://theconversation.com/if-youre-renting-chances-are-your-home-is-cold-with-power-prices-soaring-heres-what-you-can-do-to-keep-warm-184472">keep warm in a cold home</a>, they don’t have much power to make property improvements. Tenancy rules vary across Australia, but generally tenants are not allowed to make permanent changes to the house. </p>
<p>However, landlords do not benefit directly from improving the comfort or energy efficiency of their rental properties. So why do some landlords retrofit?</p>
<p>Our interviewees included landlords who had retrofitted improvements and those who had not, as well as landlords who owned high-cost and low-cost rental properties.</p>
<p><a href="https://www.sciencedirect.com/science/article/abs/pii/S2214629622000408">Our research</a> shows that, in general, landlords are not motivated to retrofit for increased rent. Nor are they motivated by environmental benefits. However, they are motivated to retrofit to improve renters’ comfort, particularly thermal comfort. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1536941143833067521"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-youre-renting-chances-are-your-home-is-cold-with-power-prices-soaring-heres-what-you-can-do-to-keep-warm-184472">If you're renting, chances are your home is cold. With power prices soaring, here's what you can do to keep warm</a>
</strong>
</em>
</p>
<hr>
<h2>What did landlords tell us?</h2>
<p>Improving renters’ comfort can benefit the landlord financially if renters stay longer in the property because this avoids vacancies and advertising costs. One landlord explained:</p>
<blockquote>
<p>“I get loyalty out of them. It’s difficult always to find new tenants. It’s time. It’s money involved. I prefer that I have tenants who stay for the long run.”</p>
</blockquote>
<p>Landlords also said they felt a responsibility to meet renters’ needs. For example, one landlord told us:</p>
<blockquote>
<p>“I think you have to be attentive to your tenants’ needs. It’s pretty much as simple as that.”</p>
</blockquote>
<p>However, landlords can only make changes to improve renters’ comfort if they are aware of renters’ discomfort. We found landlords who used a professional property manager – as about <a href="https://www.ahuri.edu.au/research/final-reports/303">three-quarters of landlords</a> do – generally knew very little about the conditions in their property and the people living in it. As one landlord said:</p>
<blockquote>
<p>“I know their name and that’s about it. I’ve never actually met them.” </p>
</blockquote>
<p>Landlords who use property managers are generally unaware of problems until renters submit a formal complaint or ask for improvements. Renters are often <a href="https://www.ahuri.edu.au/research/final-reports/338">reluctant to request improvements</a> because they worry about eviction or rental increases, or because their previous requests have not been met. </p>
<p>We also found some landlords are not concerned about renters’ comfort. These landlords are unlikely to make improvements unless governments require rental properties to meet a prescribed standard. </p>
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<iframe width="100%" height="315" src="https://www.youtube.com/embed/Xh5gfUcn4Q0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/chilly-house-mouldy-rooms-heres-how-to-improve-low-income-renters-access-to-decent-housing-116749">Chilly house? Mouldy rooms? Here's how to improve low-income renters’ access to decent housing</a>
</strong>
</em>
</p>
<hr>
<h2>What can governments do?</h2>
<p>Governments across Australia are looking at ways to <a href="https://www.energy.gov.au/government-priorities/buildings/trajectory-low-energy-buildings">improve the energy efficiency of rental properties</a>. Specifically, governments are considering requiring that energy performance be disclosed to prospective tenants and for rental properties to meet minimum energy efficiency standards. </p>
<p>While energy performance disclosure may allow landlords to charge higher rents for efficient properties, our research suggests this will not motivate them to retrofit. This is consistent with <a href="https://www.tandfonline.com/doi/abs/10.1080/09613218.2014.908265">findings from Europe</a> that energy disclosure requirements are not a strong driver of retrofitting. </p>
<p>To improve the poorest-performing rental properties, energy efficiency disclosure must be combined with enforceable minimum standards. Some standards have been introduced in recent years. For example, rental homes in Victoria are <a href="https://www.energy.vic.gov.au/energy-efficiency/minimum-rental-standards">required to have a fixed heater</a> and those heaters will be required to meet energy efficiency standards by 2023.</p>
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<p>Governments can also encourage landlords to do more than the bare minimum. Comprehensive retrofitting is needed to create healthy, low-energy homes. Government programs should aim to:</p>
<ul>
<li><p>educate landlords about conditions in their properties</p></li>
<li><p>support property managers to organise retrofits</p></li>
<li><p>protect renters from eviction or rent increases if they speak out about uncomfortable, inefficient rental properties.</p></li>
</ul>
<p>When introducing new energy-efficiency policies and incentives, governments should emphasise comfort and other benefits for tenants. Change is urgently needed to ensure Australians from all walks of life can live in comfortable, healthy and climate-resilient homes.</p><img src="https://counter.theconversation.com/content/188827/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michaela Lang undertook this research as part of a PhD that was supported by the Australian Government Research Training Program and the Victorian Government Department of Environment, Land, Water and Planning.
</span></em></p><p class="fine-print"><em><span>Ruth Lane receives funding from the Australian Research Council and the National Environmental Science Program</span></em></p><p class="fine-print"><em><span>Rob Raven 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>Tenants are rarely allowed to make permanent changes to a house. And many landlords know little about the conditions tenants endure, but most who do retrofit homes do it to improve renters’ comfort.Michaela Lang, Postdoctoral Researcher, Monash Sustainable Development Institute, Monash UniversityRob Raven, Professor and Deputy Director (Research), Monash Sustainable Development Institute, Monash UniversityRuth Lane, Associate Professor in Human Geography, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1888092022-08-17T20:04:46Z2022-08-17T20:04:46ZPeople are shivering in cold and mouldy homes in a country that pioneered housing comfort research – how did that happen?<figure><img src="https://images.theconversation.com/files/479517/original/file-20220817-10961-ju1ocy.jpg?ixlib=rb-1.1.0&rect=0%2C2000%2C4000%2C2634&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Lisa Fotios/Pexels</span></span></figcaption></figure><p>The poor state of Australia’s <a href="https://www.abc.net.au/news/2022-07-18/apartment-owners-sound-alarm-over-alleged-building-defects/101247114">residential</a>, and particularly <a href="https://www.abc.net.au/news/2022-07-16/australian-first-study-mould-biotoxin-illness/101223548">rental</a>, housing stock is attracting increasing attention. This week it has been reported many renters are living in <a href="https://www.abc.net.au/news/2022-08-16/renters-shiver-below-minimum-healthy-temperature-report-finds/101333256">unhealthily cold</a> and <a href="https://www.theguardian.com/australia-news/2022/aug/16/australian-rental-homes-colder-and-more-damp-than-who-safety-standards">damp housing</a>. The head of UNSW’s School of the Built Environment, Philip Oldfield, recently <a href="https://www.theguardian.com/commentisfree/2022/jun/13/freezing-indoors-thats-because-australian-homes-are-closer-to-tents-than-insulated-eco-buildings">described</a> the average Australian home as “closer to a tent than an insulated eco-building”. </p>
<p>A <a href="https://www.propertycouncil.com.au/Web/Content/Media_Release/National/2022/Over%20100%20organisations%20join%20forces%20in%20push%20for%20improved%20energy%20efficiency%20in%20Australian%20homes.aspx">joint statement</a> by more than 100 property, community, health and environmental organisations has called on next week’s meeting of the nation’s building ministers to increase the energy efficiency of new homes. The alliance wants to lift National Construction Code standards, such as raising the minimum thermal performance to seven stars, alongside a “whole-of-home” energy budget. The statement said Australia <a href="https://www.energymagazine.com.au/room-for-improvement-australia-and-germany-swap-notes-on-energy-efficiency-reform/">lags far behind</a> international energy-efficiency and building standards. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/if-youre-renting-chances-are-your-home-is-cold-with-power-prices-soaring-heres-what-you-can-do-to-keep-warm-184472">If you're renting, chances are your home is cold. With power prices soaring, here's what you can do to keep warm</a>
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</p>
<hr>
<p>These concerns coincide with a growing housing shortage, rising building costs and a changing climate. But these circumstances are no reason to defer housing reforms. In the past, in a remarkably similar set of circumstances, Australia became a global innovator through a dedicated government agency focused on thermal comfort and performance. </p>
<h2>We once led the way in building for the climate</h2>
<p>We must go back to the second world war, though, to see Australia at the vanguard of housing built for the climate. The Ministry of Post-war Reconstruction’s substantial and alarm-raising <a href="https://nla.gov.au/nla.obj-851519579/view?partId=nla.obj-851583656">Commonwealth Housing Report</a> of 1944 had forecast a shortfall of 300,000 dwellings by war’s end. On top of a materials shortage and a rapidly growing population, Chifley’s Labor government was keen to tackle the housing crisis head-on and to demonstrate Australia’s scientific prowess across a range of technical industries. </p>
<p>As the magnitude of the looming housing shortage became clear, a group of architects established a Small House Bureau to reinvigorate the housing landscape. In Victoria, the director was celebrated architect Robin Boyd. He advocated for smaller homes, notably if the main building material could be earth. </p>
<p>Boyd <a href="https://trove.nla.gov.au/newspaper/article/206872165?searchTerm=The%20materials%20are%20already%20on%20%E2%80%98your%20vacant%20building%20site">told a growing readership</a> desperate for cost-effective and accessible alternatives that earth walls were “cheap, strong, weatherproof, and highly insulating”. The materials are already on “your vacant building site”, he cried. Thus, it seemed reasonable to “make it of mud!”.</p>
<p>At the same time, the Commonwealth Experimental Building Station was set up on 16 hectares of bushland in Ryde, north of Sydney. Its mandate was to carry out experimental construction in different climatic and geographic locations. It was also to advise regulators, housing authorities and government departments. </p>
<p>Engineers, builders, architects and the public welcomed the innovative scientific approach to housing design across the nation’s varied and extreme weather and seasonal conditions. Post-war architects and scientists were keen to place a climatically defined framework on both the layout and construction of Australian homes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of Australian climate zones from a study of the thermal performance of housing" src="https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=696&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=696&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=696&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=874&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=874&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479326/original/file-20220816-2656-5u5jp5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=874&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 of Australian climate zones from a 1950 study of the thermal performance of housing.</span>
<span class="attribution"><span class="source">J.W. Drysdale, The Thermal Behaviour of Dwellings Technical Study/Commonwealth Experimental Buildings Station</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>One of the station’s main directives was to address “heating, lighting, ventilation, sound and thermal transmission, and performance generally”. The station developed an advanced thermal modelling program to enhance indoor comfort. The modelling took into account solar radiation, the value of shading, strategic ventilation and insulation. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/house-hunters-are-rarely-told-the-home-energy-rating-little-wonder-the-average-is-as-low-as-1-8-stars-144873">House hunters are rarely told the home energy rating – little wonder the average is as low as 1.8 stars</a>
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<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The cover of Build Your House of Earth by George F. Middleton" src="https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=902&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=902&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=902&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1134&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1134&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479566/original/file-20220817-14-8is33a.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1134&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Build Your House of Earth by George F. Middleton.</span>
</figcaption>
</figure>
<p>Amidst a slew of controlled experiments, the station’s chief technical officer, English architect and engineer George Middleton, championed the practical application of earth walls. Following a scoping tour of England, America, Russia and across Australia, Middleton examined the structural integrity, durability and effective function of “Pisé” or rammed earth. </p>
<p>A devotee of the aesthetic qualities and durability of earth, he produced several technical papers that placed earth walls “high among the accepted building methods”.</p>
<p>Continuing to advocate for earth over prefabricated materials, Middleton released Build Your House of Earth in 1953. It remains the authoritative text on rammed-earth building in Australia. </p>
<p>In just a few short years, the station researched, experimented and built dozens of prototypes. Its thermal response analysis tool (replicated 20 years later by UK building authorities) was ground-breaking. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1449025015450509315"}"></div></p>
<h2>Australia needs to make up lost ground</h2>
<p>Despite the station’s record of achievement, its funding for such investigations was cut in 1955. Some thermal investigations were all but abandoned. Without ongoing testing and field application, the capacity to influence material and performance standards waned. </p>
<p>The station did continue to provide regulations and standards for building systems and materials, and it was restructured in the mid-1980s into the National Building Technology Centre. It was later absorbed into CSIRO’s Division of Building, Construction and Engineering, which still oversees the Building Code of Australia. </p>
<p>At the centre of building research in Australia, the station was innovative and experimental. It was created decades before the energy conservation movement began to investigate building efficiency <a href="https://neep.org/blog/reflecting-history-energy-efficiency-while-looking-future">in North America and England</a>. </p>
<p>But our innovation and desire for experimentation have faded. Decades of industry lobbying, <a href="https://theconversation.com/buck-passing-on-apartment-building-safety-leaves-residents-at-risk-119000">toothless enforcement</a>, a lack of investment in and subsidies for refurbishing existing dwellings, and an outdated rating scheme (<a href="https://www.nathers.gov.au/">NatHERS</a>) have left many Australians out <a href="https://www.abc.net.au/news/2022-08-16/renters-shiver-below-minimum-healthy-temperature-report-finds/101333256">in the cold</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/keen-to-retrofit-your-home-to-lower-its-carbon-footprint-and-save-energy-consider-these-3-things-175921">Keen to retrofit your home to lower its carbon footprint and save energy? Consider these 3 things</a>
</strong>
</em>
</p>
<hr>
<p>In a continent notorious for its extremes, it is time to invest again in thermal research and testing. Australia needs to build resilience into new and existing houses. In a rapidly changing climate, we must consider the capacity and efficiency of earth and other natural materials as a viable and proven alternative to prefabricated materials.</p><img src="https://counter.theconversation.com/content/188809/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rachel Goldlust is affiliated with the Renters and Housing Union. </span></em></p>Housing standards in Australia have slipped behind the rest of the world. But momentum is growing to revive past ambitions to build the best homes we can.Rachel Goldlust, Adjunct Research Fellow, School of Archaeology and History, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1786332022-03-09T02:02:37Z2022-03-09T02:02:37ZThinking of buying a dehumidifier? Advice from an expert on mould and damp<figure><img src="https://images.theconversation.com/files/450832/original/file-20220309-21-1iyjjqz.jpg?ixlib=rb-1.1.0&rect=16%2C64%2C5385%2C3663&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Google searches for “dehumidifier” have <a href="https://trends.google.com/trends/explore?date=today%201-m&geo=AU&q=dehumidifier">soared</a> in the past month, especially in New South Wales, and there are a lot of options to choose from. </p>
<p>But how much moisture can these things really remove? And what happens if you just ignore the problem?</p>
<p>I’ve researched mould and indoor air quality, and work with clients helping address mould problems in homes. Here’s what you need to know on where a dehumidifier can help, and when it’s more likely just a band-aid for a deeper problem.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sudden-mould-outbreak-after-all-this-rain-youre-not-alone-but-you-are-at-risk-177820">Sudden mould outbreak after all this rain? You’re not alone – but you are at risk</a>
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</em>
</p>
<hr>
<h2>Reduce moisture through big and small fixes</h2>
<p>Too much moisture can cause your house and belongings to go mouldy. A bad smell soon follows.</p>
<p>Balancing that moisture to ensure we live in healthy, comfortable spaces while controlling mould and microbial growth is a challenge. Sometimes we can be notoriously bad at ventilating domestic spaces appropriately.</p>
<p>I see a dismayingly frequent number of bathrooms without an extraction fan. Or laundries with clothes driers, pumping hot wet air into the room with no system to get that moisture outside. </p>
<p>In fact, the way we live in often well-sealed houses can trap lots of the moisture we sweat and steam off though everyday activities.</p>
<p>Showers, cooking, sweating and drying clothes produce anywhere from <a href="https://www.umweltbundesamt.de/en/publikationen/guideline-mould">six to 12 litres of indoor moisture</a> per person every day.</p>
<p>A dehumidifier might reduce moisture in a house but it won’t fix the underlying problem if your house has insufficient systems to re-route moisture outside.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A fan in a bathroom" src="https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450834/original/file-20220309-17181-m5z7aj.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">Wherever possible, moisture should be re-routed outside.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>So would a dehumidifier help?</h2>
<p>But if you’re renting or short on cash, and circumstances prevent you adding an extraction fan, a dehumidifier will at least help keep things under control. </p>
<p>You’ll need to do a little research to make sure you’re buying a dehumidifier that’s powerful enough to get the job done.</p>
<p>Most “mid-range” units state they’re capable of pulling somewhere around three to 15 litres of water out of the air per day. </p>
<p>That’s probably enough to help in some areas. But moisture will spread itself through the whole house. </p>
<p>This figure also doesn’t take into account how much moisture is in the air naturally, with higher natural relative humidity in Queensland and Darwin particularly making this more of an uphill battle. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1501076586325766144"}"></div></p>
<p>So how much help would a dehumidifier actually be? That depends on how much water is in the air.</p>
<p>One cubic metre of air has 1,000 litres of volume, and at 20°C can hold about 17 grams of water. </p>
<p>Reduce that temperature to 10°C and it can only hold around 10g. But up the temperature to 30°C and it can hold around 30g of water. </p>
<p>So, given a normal 3x4-metre lounge room in the middle of spring in a relatively dry place like Adelaide, you’ve probably got 200-300 millilitres of water in the air. With air flowing in and around the house and different rooms, you’re starting to approach a few litres of natural moisture just hanging around.</p>
<p>If you’re in Darwin, or a state contending with weeks of seemingly endless rain, you can probably double your calculations. You might have <em>tens of litres</em> of water to remove from the air throughout the house over the course of the day.</p>
<p>Without some seriously big dehumidifiers, you simply won’t be able to overcome that problem without being targeted in your approach.</p>
<p>In these cases, you’ll be most successful where you can control the amount of outside air coming in, and by placing the dehumidifier in the affected area with good air circulation around it. So keep windows closed when it’s rainy and put the dehumidifer in the most moisture-laden part of the house.</p>
<p>Should you also keep the door closed to help the dehumidifier work best on a particular room, or is it better so open doors so as to reduce humidity throughout the house? Well, if you know you’ve got it located at source, a closed space can help. But it’s a balancing act.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450836/original/file-20220309-13-wmyg4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Too much moisture can cause your house and belongings to go mouldy. A bad smell soon follows.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Getting the balance right</h2>
<p>If your home has been flooded, a dehumidifier of any size is at best only a small part of the solution. Significant volumes of building materials and soft furnishings will need to be disposed of and assessed for warping or structural damage. </p>
<p>In these instances, professional drying is required and there are some seriously powerful dehumidifiers on the market. </p>
<p>But these are often used inside contained spaces where damaged rooms are sheeted in plastic to limit the flow of outside air (bringing in more moisture). </p>
<p>While there are rules about toxic chemicals and airborne hazards in workplaces, Australia is sorely lacking when it comes to regulations on comfortable indoor humidity and mould spores.</p>
<p>The guidance <a href="https://www.ashrae.org/">documents</a> most frequently referred to tend to indicate a comfortable indoor humidity sits between 30-60% relative humidity, and that bringing indoor relative humidity to below 65% tends to notably reduce microbial growth. </p>
<p>However, pushing the relative humidity too low can be uncomfortable. It can dry out your eyes, skin and mucous membranes, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4097773/">increase</a> some infection risks and may cause long term damage to materials (such as wood – particularly decorative wood – and some paper objects, art and some styles of heritage flooring).</p>
<h2>So would a dehumidifer be a waste of money once the rain stops?</h2>
<p>When the rain stops, have you just wasted your money on an expensive piece of kit? Would one of those cheap little DampRid pots full of moisture-absorbent crystals or powder have been enough? </p>
<p>Not likely. Desiccants such as DampRid pots can help in closed boxes or where you’ve only got a small air space. But at best, they generally only pull about three times their weight in moisture out of the air; a 300g pot might capture nearly a litre of water, but that’s it. </p>
<p>So dehumidifiers can help if you’re clever with that you’re trying to achieve, but you should always look to solve the underlying cause. That means, where possible, looking to improve your exhaust and ventilation.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fungi-after-the-floods-how-to-get-rid-of-mould-to-protect-your-health-111341">Fungi after the floods: how to get rid of mould to protect your health</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/178633/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Taylor provides consulting services in the area of indoor air quality and mould assessment for Greencap. He has previously received funding from SafeWork SA.</span></em></p>Dehumidifiers can help if you’re clever with that you’re trying to achieve, but you should always look to solve the underlying cause. That means, where possible, improving exhaust and ventilation.Michael Taylor, Adjunct academic, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1778202022-03-01T23:06:38Z2022-03-01T23:06:38ZSudden mould outbreak after all this rain? You’re not alone – but you are at risk<figure><img src="https://images.theconversation.com/files/449086/original/file-20220301-4202-15f1d2z.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5991%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Recent torrential rain along the east coast of Australia has sparked renewed fears of <a href="https://www.abc.net.au/news/2022-01-20/black-mould-warning-after-wet-weather-soaks-nation/100768710">mould in people’s homes</a>, which can cause dangerous health problems. Many flood-affected residents in northern New South Wales and Queensland will also be contending with mould as part of the post-flood cleanup.</p>
<p>Moulds are fungi – microbes like <a href="https://theconversation.com/microbes-our-tiny-crucial-allies-69536#:%7E:text=A%2520%25E2%2580%259Cmicrobe%25E2%2580%259D%2520is%2520a%2520bacterium,see%2520with%2520the%2520naked%2520eye">viruses or bacteria</a>. There are <a href="https://theconversation.com/the-new-architectural-frontier-buildings-and-their-microbiomes-139777">some microbes in every building</a> and they’re usually harmless. </p>
<p>In a damp or water-damaged environment, however, toxic mould species grow and release spores that can cause health problems if inhaled.</p>
<p>Here’s what you need to know.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/floods-herald-creeping-problem-of-mould-and-growing-health-risks-5928">Floods herald creeping problem of mould and growing health risks</a>
</strong>
</em>
</p>
<hr>
<h2>More than just lungs: mould can affect health in other ways</h2>
<p>Many of us know someone whose asthma is triggered by exposure to mould. But even non-asthma sufferers are at risk. </p>
<p>Research shows dampness, mould and related airborne particles are associated with a <a href="https://theconversation.com/health-check-how-does-household-mould-affect-your-health-48341">range of adverse health outcomes</a>, including increased risks of asthma, allergies, and respiratory infections and symptoms.</p>
<p>A parliamentary <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/House/Health_Aged_Care_and_Sport/BiotoxinIllnesses/Report">Inquiry into Biotoxin-related Illnesses in Australia</a> noted the need for further research into mould prevalence, mould measurement and the potential health effects of exposure to damp and mould.</p>
<p>Some research suggests people exposed to mould in their homes report <a href="https://www.ajpmonline.org/article/S0749-3797(19)30170-9/fulltext">more severe depression and anxiety symptoms</a>. Of course, this association isn’t just about mould, and worsening mental health is likely to do with <a href="https://www.sciencedirect.com/science/article/pii/S0033350614003035">a range of factors</a> associated with living with damp and mould, <a href="https://www.theguardian.com/housing-network/2016/feb/04/poor-housing-bad-mental-health">including poor housing condition, poverty, and general ill health</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449088/original/file-20220301-17-sqj4qv.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">Heavy rain and floods lead to excess indoor moisture, and a damp environment is perfect for mould growth.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Mould hot spots in Australia</h2>
<p>The World Health Organisation advises <a href="https://www.who.int/publications/i/item/9789241550376">no level of exposure to mould can be considered safe</a> for health. It says dampness and mould-related problems should be prevented and remediated early to avoid potentially harmful exposure.</p>
<p>Despite this strong advice, mould is a common problem in Australia. Until recently, not much has been known about mould prevalence, with the official WHO guidelines on indoor air quality estimating <a href="https://www.euro.who.int/__data/assets/pdf_file/0017/43325/E92645.pdf">10-50% of Australian homes are affected by dampness and mould</a>. </p>
<p>We can also make an estimate using the large-scale <a href="https://pubmed.ncbi.nlm.nih.gov/35110558/">Australian Rental Housing Conditions Dataset</a>, which collates robust data collected from over 14,000 rental households in 2020. </p>
<p>Our analysis of this data set shows 27% of renters say their current home has problems with mould and 21% report problems with dampness.</p>
<p>Mould is often found in the south eastern states of Australia due to a combination of lower temperatures and damp weather. It is also a problem in New South Wales and Queensland, where 39% and 26% of regions respectively have a high prevalence of mould in rental homes. Sydney has more mould than Melbourne.</p>
<p>We have mapped the data for Melbourne, Sydney and Brisbane here:</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=317&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=317&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=317&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=398&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=398&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449348/original/file-20220301-19-15h4je2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=398&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Data source: the Australian Rental Housing Conditions Dataset.</span>
<span class="attribution"><span class="source">Centre for Research Excellence in Healthy Housing</span></span>
</figcaption>
</figure>
<p>You’re also more likely to find mould in poorly maintained, low-income housing. These poor housing conditions are more common among people who <a href="https://www.ahuri.edu.au/sites/default/files/migration/documents/Rental-Insights-A-COVID-19-Collection.pdf">already experience health issues</a>. </p>
<p>Children are another group at higher risk of living in housing with mould – 33% of people living with two or more children reported mould in the Australian Rental Housing Conditions Dataset (compared to 27% of childfree households). </p>
<p>Other risk factors for mould included roof and plumbing defects, and the need for urgent repairs.</p>
<h2>Building codes and rental policy can help</h2>
<p>Mandated building standards are important to ensure design, building and maintenance sufficiently address mould growth.</p>
<p>Our current building codes do not focus on preventing damp conditions. In fact Australia’s National Construction Code previously inadvertently promoted moist indoor environments by solely focusing on <a href="https://www.tandfonline.com/doi/full/10.1080/00038628.2019.1703636">well-sealed, energy-efficient buildings</a>. </p>
<p>The National Construction Code is to be <a href="https://www.abcb.gov.au/news/2022/ncc-2022-preview-and-adoption-dates">updated in late 2022</a>. Hopefully, the new code will directly address the mould-promoting condensation problem caused by measures to increase energy efficiency in buildings.</p>
<p>New builds, of course, don’t house the whole population. Almost a third of Australian households <a href="https://www.abs.gov.au/statistics/people/housing/housing-occupancy-and-costs/latest-release">rent</a>, and this includes older homes with a range of structural issues. Policies targeting renters and landlords could have a significant impact on population health.</p>
<p>While tenancy regulations vary across Australia, some states and territories have begun to address the issue of mould in rental housing.</p>
<p>For example, the recent Victorian rental reform <a href="https://www.consumer.vic.gov.au/housing/renting/repairs-alterations-safety-and-pets/minimum-standards/minimum-standards-for-rental-properties">mandates</a> premises:</p>
<blockquote>
<p>must be free from mould and damp caused by or related to the building structure.</p>
</blockquote>
<p>It allows tenants to log an urgent repair request where issues, such as leaking roofs or plumbing, lead to mould.</p>
<p>Since there are <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ina.12550">no accepted standards for mould measurement or remediation</a>, legislation referring to “mould and damp” may not end up improving housing conditions.</p>
<p>An agreed definition of what level of mould is harmful, and how it can be measured, would allow governments to set cut-offs above which homeowners are compelled to intervene.</p>
<h2>What can you do about mould in your home?</h2>
<p>Prevention is more efficient than removal. The key is keeping the house dry and free of dust. Make sure you:</p>
<ul>
<li><p>fix leaks, including roofs and walls as well as plumbed appliances such as dishwashers</p></li>
<li><p>increase ventilation and air circulation with windows and fans</p></li>
<li><p>use extractor fans when cooking, bathing or drying laundry</p></li>
<li><p>use a dehumidifier</p></li>
<li><p>clean condensation from inner windows.</p></li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449090/original/file-20220301-19-186shfx.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">Use extractor fans when cooking, bathing or drying laundry.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>If mould has already set in, the best option is to <a href="https://www.facs.nsw.gov.au/housing/living/health-safety-savings/mould/chapters/how-to-remove-mould#:%7E:text=Use%20a%20mild%20detergent%20like,after%20wiping%20mould%20off%20surfaces">remove it physically with a microfibre cloth</a>.</p>
<p>Mould remediation is complex and often best undertaken with professional advice. Australian state and territory governments provide advice on dealing with dampness and mould in the home.</p>
<p>For example, see advice sheets from the <a href="https://www.health.vic.gov.au/publications/removing-mould-at-home">Victorian Department of Health</a>, <a href="https://www.health.nsw.gov.au/environment/factsheets/Pages/mould.aspx">NSW Health</a> and the <a href="https://www.qld.gov.au/community/disasters-emergencies/disasters/phys-health-wellbeing/mould">Queensland government</a>. </p>
<p>This <a href="https://www.healthyhousing-cre.org/mould">explainer</a> by the <a href="https://www.healthyhousing-cre.org/">Healthy Housing Centre of Research Excellence</a> on mould and damp also provides information on where you can seek help.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/queenslanders-at-risk-from-mould-as-flood-clean-up-continues-11935">Queenslanders at risk from mould as flood clean-up continues</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/177820/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Bentley receives funding from the National Health and Medical Research Council and the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Ang Li receives funding from the University of Melbourne Early Career Researcher Grant Scheme and funding support from the National Health and Medical Research Council.</span></em></p>In a damp or water-damaged environment, toxic mould species grow and release spores that can cause health problems if inhaled.Rebecca Bentley, Professor of Social Epidemiology, Principal Research Fellow in Social Epidemiology and Director of the Centre for Research Excellence in Healthy Housing in Melbourne School of Population and Global Health, The University of MelbourneAng Li, Research Fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1113412019-02-11T19:12:30Z2019-02-11T19:12:30ZFungi after the floods: how to get rid of mould to protect your health<figure><img src="https://images.theconversation.com/files/258169/original/file-20190211-174851-1908pcu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mould isn't just unsightly – it can be dangerous for our health.</span> <span class="attribution"><span class="source">From shutterstock.com</span></span></figcaption></figure><p>As Townsville residents continue the clean-up following January’s flooding, microscopic fungi, commonly called mould, will be a concern for many.</p>
<p>Homes and buildings affected by the floods will likely remain inaccessible for a period of time, and with relatively high ambient temperatures and lots of water with nowhere to go, mould will in many cases begin to take hold.</p>
<p>If your home has been affected by water, there are measures you can take to prevent mould from developing. And if the fungi has already started to grow, it’s important to thoroughly remove it – as the presence of mould can affect our health.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/after-the-floods-come-the-mosquitoes-but-the-disease-risk-is-more-difficult-to-predict-111173">After the floods come the mosquitoes – but the disease risk is more difficult to predict</a>
</strong>
</em>
</p>
<hr>
<h2>How does mould develop?</h2>
<p>Mould growth begins with water damage. You can generally resolve the problem by fixing the leak, drying the water and installing a fan. These steps should be taken as quickly as possible.</p>
<p>Left unchecked, spores from common fungi such as <em>Penicillium</em> and <em>Aspergillus</em> can germinate <a href="https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2672.2003.01909.x">within 16 hours</a>, and can grow millimetres a day. Within <a href="https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2672.2003.01909.x">a few weeks,</a> wet materials can be heavily colonised.</p>
<p>Fungi are more attracted to materials which, at least in their original form, would have been found in the environment. So mould will readily consume many materials in our homes which used to be plants, such as timber and cardboard. But many fungi aren’t fussy and will happily degrade paints and glue, and grow <a href="https://www.sciencedirect.com/science/article/pii/S0964830501001032">in dust and dirt</a> found in carpets and insulation.</p>
<p>Often a musty smell is noticeable before we see the signs of brown, green and black discolouration. Most of the time by this point simply wiping the surfaces clean is unlikely to solve the problem.</p>
<p>In terms of mould growth, flood water can be more problematic than clean water, as it will have picked up dirt, sewage and other nutrient-rich materials along the way. This will not only increase the amount of spores splashed onto surfaces, but also provide a food source for fungi as they begin to multiply. This can make clean-up efforts significantly more difficult.</p>
<h2>Getting rid of it</h2>
<p>Non-porous materials like ceramics, glass, metal and plastics can be relatively easily cleaned using household detergents, because the mould can’t penetrate and multiply within.</p>
<p>Clothes, curtains and fabric items can usually be laundered or dry cleaned, but items like couches and pillows are <a href="https://www.tandfonline.com/doi/abs/10.1080/15459620490462823">frequently impossible</a> to adequately clean once fungi have colonised.</p>
<p>Unfortunately papers and books, plasterboard, insulation, and some wooden items will just need to be replaced.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/258172/original/file-20190211-174857-119ozz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/258172/original/file-20190211-174857-119ozz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/258172/original/file-20190211-174857-119ozz0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/258172/original/file-20190211-174857-119ozz0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/258172/original/file-20190211-174857-119ozz0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/258172/original/file-20190211-174857-119ozz0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/258172/original/file-20190211-174857-119ozz0.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">You might be able to clean up some mould yourself. In other cases it may be better to seek professional help.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
</figcaption>
</figure>
<p>Wiping mould growth off a ceiling or wall using household cleaning products <a href="https://oeh.tandfonline.com/doi/abs/10.1080/15459620600798663#.XGDhjy1L1Bw">may be effective</a> on small areas not impacted by flood waters. However for areas larger than a square metre with <a href="https://www.ncbi.nlm.nih.gov/pubmed/22286589">heavy growth</a> or impacted by dirty water, regular cleaning will simply remove the spores from the surface, leaving the material colonised by mould underneath.</p>
<p>There’s no easy fix in these cases, particularly if buildings have been left closed up and wet for several weeks. It’s frequently more time and cost efficient to replace the damaged areas than attempt to scrub, bleach, vacuum and repaint an entire home.</p>
<h2>Health concerns</h2>
<p>Aside from the cosmetic aspect of mould, there are health concerns which may arise from fungi-contaminated buildings.</p>
<p>Fungal spores and cells often act as allergens. <a href="https://www.tandfonline.com/doi/abs/10.1080/10473220301451">When inhaled,</a> they can cause shortness of breath and cold and flu-like symptoms as well as itchy eyes and skin.</p>
<p>Fortunately, inhaled spores rarely cause genuine infection, with most healthy individuals being at <a href="https://www.jacionline.org/article/S0091-6749(05)02591-1/fulltext">very low risk</a> of developing further illness.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-your-home-harming-you-asthma-allergies-and-indoor-mould-23257">Is your home harming you? Asthma, allergies and indoor mould</a>
</strong>
</em>
</p>
<hr>
<p>Another area we’re beginning to understand more is mycotoxins – the toxic compounds produced by some fungi as they grow. Imported food products are tested for mycotoxins frequently, but it’s more difficult to test their risk in <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ina.12182">indoor air.</a></p>
<p>Not all fungi produce these toxic metabolites, and there’s no simple test or mould colour that can tell you if you’ve got one of the bad ones growing in your home. It generally requires experts to sample the spores and determine what species of fungi is present. </p>
<p>We also don’t know much about the behaviour of mycotoxins in buildings – how many accumulate in different materials – or have any simple ways to <a href="https://www.ncbi.nlm.nih.gov/pubmed/22286589">remove them</a> once they turn up. </p>
<p>For most people with low level mould problems, mycotoxins will not be an issue. But after large scale water damage events like flooding, explosive mould growth may produce concentrations of toxins high enough to pose a risk of severe respiratory distress, bleeding from the lungs, <a href="https://www.ncbi.nlm.nih.gov/pubmed/11669391">inflammation</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/15477176">cognitive impairment</a>, or <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2557730/">cancer</a>.</p>
<h2>Protecting yourself</h2>
<p>Although this may sound frightening, if you’re able to fix the moisture first, mould shouldn’t be an issue. But it’s important to be thorough. Wall cavities, roof spaces and insulation will hold onto water.</p>
<p>If mould does develop, small amounts can be conquered – particularly on hard surfaces or items that can be thrown away. Wear gloves, a dust mask or respirator, and long sleeved clothes when tackling a clean-up.</p>
<p>Seek expert advice early to deal with large scale growth (more than one square metre), or to determine how best to proceed when drying your home to make sure it stays fungi free.</p><img src="https://counter.theconversation.com/content/111341/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Taylor provides consulting services in the area of indoor air quality and mould assessment. He has previously received funding from SafeWork SA .</span></em></p>The aftermath of flooding provides the perfect breeding ground for mould in our homes. It’s important to properly remove it so it doesn’t affect our health.Michael Taylor, Adjunct academic, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/924292018-02-28T05:13:25Z2018-02-28T05:13:25ZMould levels seen at Nauru detention centre are enough to cause serious health problems<p>A series of recent <a href="https://www.theguardian.com/world/2018/feb/23/nauru-refugees-asylum-seekers-and-staff-exposed-to-highly-toxic-mould">reports by The Guardian</a> have revealed refugees, asylum seekers and staff at the Nauru processing centre have been exposed to a mould problem of “<a href="https://www.theguardian.com/world/2018/feb/23/nauru-mould-problem-was-of-epic-proportions-microbiologist-says">epic proportions</a>”. </p>
<p>The fungal growth in housing and working areas has reportedly led to some staff describing ongoing health effects including cognitive impairment and chronic lung infections. According to The Guardian:</p>
<blockquote>
<p>At least a dozen former staff who have worked in the regional processing centre are understood to have developed conditions from exposure to mould and breathing the contaminated air in the buildings.</p>
</blockquote>
<p>More than 300 refugees and asylum seekers, including 36 children, still live in mould-prone tents on Nauru, despite the government having been repeatedly warned of the health risks.</p>
<p>Assuming the photos and videos obtained by The Guardian accurately represent the extent of the problem – which looks quite extreme – it’s fair to assume there would be some negative health consequences, particularly in those who have allergies or a lower immunity. However, the association between cognitive impairment and mould exposure is a <a href="https://www.ncbi.nlm.nih.gov/pubmed/16131339">contested area</a> of research. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-does-household-mould-affect-your-health-48341">Health Check: how does household mould affect your health?</a>
</strong>
</em>
</p>
<hr>
<h2>Levels of mould</h2>
<p>Mould accumulates in damp and poorly ventilated buildings. And enclosed rooms on a tropical island are particularly good environments for this sort of growth.</p>
<p>The Guardian reports tests carried out at Nauru, by microbiologist Dr Cameron Jones, indicated levels of mould around <a href="https://www.theguardian.com/world/2018/feb/23/nauru-refugees-asylum-seekers-and-staff-exposed-to-highly-toxic-mould">60-70 times higher</a> than normal range.</p>
<p>When conducting an investigation for mould growth and indoor air quality, the general rule is if there’s visible mould growth on surfaces, there’s a good chance there’s a problem. Large areas of visible mould tend to mean a bigger problem. </p>
<p><a href="https://inspectapedia.com/sickhouse/Australian_Mold_Guideline-2005.pdf">Areas of mould growth</a> greater than one square metre of mould indicate a mid-level problem, and areas greater than 10 square metres a serious problem.</p>
<p>A common thing to look for is the number of airborne spores that the mould is producing. Microbiologists usually take samples from a non-problem area and outside, and then compare the number of spores to the mouldy room. </p>
<p>Such a test in a major city would probably find around 500 spores (known as colony forming units) <a href="http://journals.sagepub.com/doi/abs/10.1177/1420326X13499172">per cubic metre of air</a> outside, and less than half that inside buildings. This number is quite normal and likely to be up to double in summer and autumn, and sometimes half that in spring and winter. </p>
<p>So if your measurement is 10 or 100 times greater than those numbers, you probably have a serious problem. </p>
<p>The photos from Nauru suggest many areas greater than one square metre of fungal growth, and some areas greater than 10 square metres. This would likely mean the number of airborne spores is in the 10-100 times the normal range, maybe even 1,000 times higher.</p>
<h2>Health impacts</h2>
<p>Several factors play a part when determining what kind of risk such levels of mould exposure can pose to human health.</p>
<p>Spores in this concentration may cause <a href="http://www.who.int/indoorair/publications/7989289041683/en/">allergy-type symptoms</a> such as a runny nose, itchy eyes and skin, wheezing, sensitisation to other allergens, and general discomfort in <a href="https://www.ncbi.nlm.nih.gov/pubmed/11036728">exposed individuals</a>. </p>
<p>Infection from these airborne spores (mycosis) is typically uncommon. It occurs mainly in those with <a href="https://www.ncbi.nlm.nih.gov/pubmed/12069910">compromised immune systems</a>, such as people receiving chemotherapy, those who have received organ transplants, and those with autoimmune diseases. </p>
<p>However, the volatile and airborne compounds (mycotoxins) produced by certain species of mould, particularly from the genus <em>Stachybotrys</em>, and certain species of <em>Aspergillus</em> and <em>Penicillium</em> can be <a href="https://www.ncbi.nlm.nih.gov/pubmed/11036728">seriously harmful to human health</a>. These can cause pulmonary (lung) haemorrhage (bleeding), increase the risk of cancer, suppress the immune system and airways and cause lung inflammation. </p>
<p>If these toxic species are present, even smaller areas of contamination are treated as a problem.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hidden-housemates-meet-the-moulds-growing-in-your-home-54743">Hidden housemates: meet the moulds growing in your home</a>
</strong>
</em>
</p>
<hr>
<p>The Guardian has reported former staff indicating ongoing respiratory illness, fatigue and, in one case, cognitive disability. There is <a href="https://www.ncbi.nlm.nih.gov/pubmed/19854819">little research</a> done when it comes to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3179161/">such conditions</a> resulting from a fungal origin. The results are <a href="https://www.ncbi.nlm.nih.gov/pubmed/16131339">contentious</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/17362145">debated</a> and unfortunately very hard to attribute to mycotoxin exposure. </p>
<p>It seems plausible that continued exposure, causing inflammation and pain in the face, neck and upper airway, combined with the likely effect of reduced sleep quality, could result in ongoing fatigue in workers and residents. This is a theoretical position though, and not based on any first-hand evidence.</p>
<p>It seems clear there’s a lot of mould growing at the Nauru processing facility. It also seems very likely staff and residents were in a position to be exposed to fungal spores and possibly any compounds produced by the mould present. </p>
<p>But working out who was exposed, for how long, in what concentration, to what spores, combined with each individual’s health status at the time, unique sensitivities and immune systems results, is a large ball of wool to untangle. </p>
<p>Attributing the cause of these health effects so long after exposure can make detection of mycotoxins, their breakdown products, or biomarkers, in exposed individuals very difficult.</p><img src="https://counter.theconversation.com/content/92429/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Taylor has previously received funding from SafeWork SA. </span></em></p>Several factors play a part when determining what kind of risk high levels of mould exposure can pose to human health.Michael Taylor, Adjunct academic, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/752122017-08-22T01:55:27Z2017-08-22T01:55:27ZExplainer: why do we get fungal nail infections and how can we treat them?<figure><img src="https://images.theconversation.com/files/165997/original/file-20170420-2401-bharar.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">People suffering fungal nail infections are often very distressed by the disfigurement they cause. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><a href="https://www.ncbi.nlm.nih.gov/pubmed/20831675">About 10% of us</a> (including 20% of people over 60 and 50% of people over 70) suffer from fungal nail infections. So why do we get them, and does it matter? </p>
<p>Technically called “onychomycosis”, fungal infection of the nail plate (the hard outer nail) or nail bed (that lies under the hard nail) will most often appear as yellowish, white, black or green discolouration of the nail. The infected nail may also appear thickened or brittle. In severe cases, from long-term infection (where all the tissues of the nail have been infected), the infected nail may break up and fall off. </p>
<p>Fungal nail infections can be difficult to cure, and they typically don’t go away without antifungal treatment. The fungus can spread to other areas of the hands or feet, and can be mild with purely cosmetic implications, or more severe with pain, low self-esteem and embarrassment due to disfigurement.</p>
<p>Toenails are more often affected than fingernails, possibly because they’re larger, slower to grow, suffer pressure from footwear, often have poorer hygiene, and are often in a closed environment (shoes) where fungi can grow. </p>
<p>Although fungal nail infections are not life-threatening, they’re an important health problem because of their high prevalence and poor response to therapy.</p>
<p>Fungal nail infections are thought to have become more prevalent during the 20th century thanks to people migration, longer life expectancy, increasing numbers of people with compromised immune systems (such as HIV sufferers), use of stifling foot wear and locker rooms in the gym.</p>
<h2>Causes and symptoms</h2>
<p>Fungal nail infections are caused by different types of fungi, yeasts (such as Candida) and moulds. Fingernail fungal infections are typically caused by yeast fungi, especially Candida.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166000/original/file-20170420-2395-ce7gst.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">Fungal infection of the fingernails is less common than toenails.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>Fungal nail infections are <a href="https://www.ncbi.nlm.nih.gov/pubmed/23957642">more common among people</a> who are of lower socioeconomic background, older, male, diabetic, obese, immune deficient (such as HIV or cancer), lacking personal hygiene, and environmental factors such as fungal contamination of swimming pools, public toilets and communal bathing facilities.</p>
<p>One of the problems with treating fungal nail infections is the fungus that causes it is difficult – if not impossible – to eliminate from the environment. These fungi thrive in warm, moist environments that you typically find in gyms, swimming pools, bathrooms, socks of unnatural fibres and enclosed shoes. </p>
<p>Because fungal spores can remain viable for months in these environments, frequent exposure can increase the risk of infection (and re-infection). Fungal spores can be picked up in many ways – such as wearing shoes that harbour the organism, by walking barefoot in areas where the fungus is prevalent (especially public showers and locker rooms), by wearing wet shoes or socks for long periods, through previous injury to the toe or toenail that opens a path for easy entry of the fungus, or by wearing improperly-fitting shoes. </p>
<p>Fungal infection occurs when the organism invades through an opening in the nail, meaning fungi will usually attack nails that are already damaged. After infection occurs, the growth of the fungi leads to mild inflammation, which causes the nail to thicken and the nail plate to detach from the nail bed. The space underneath the nail can then serve as a reservoir for bacteria and moulds, which can cause the nail to become discoloured.</p>
<h2>Diagnosis and treatment</h2>
<p>Fungal nail infections and the resultant nail destruction can promote other sources of infection like cellulitis (a bacterial skin infection) and other forms of tinea, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5120551/">aggravate foot problems</a> resulting from other illnesses such as diabetes. Diagnosis is usually confirmed by looking at nail clippings through a microscope or other tests before starting treatment.</p>
<p>Treatment may not be required if the infection is minor. The severity is judged by looking at the degree of discolouration, nail thickening and pain. </p>
<p>Topical agents such as amorolfine (Loceryl 5% nail lacquer; applied once or twice a week) and ciclopirox (Penlac 8% nail lacquer; applied daily) are usually prescribed for mild forms of the disease, but the treatment periods are long and their <a href="https://www.ncbi.nlm.nih.gov/pubmed/20831675">efficacy is somewhat limited</a> due to poor nail plate penetration. These medications kill fungi by <a href="https://www.ncbi.nlm.nih.gov/pubmed/10515900">interfering with their cell membranes</a>, which leads to their death.</p>
<p>For more severe cases, oral antifungal medications might be required. These include fluconazole (an antifungal agent also commonly used to treat thrush), terbinafine (a broad-spectrum antifungal) and griseofulvin (usually used for skin infections). The latter is a very old drug and carries the risk of causing damage to the liver. Terbinafine is most effective and therefore is the preferred oral treatment. A 12-week course <a href="http://www.amh.hcn.net.au/view.php">cures 70-80% of cases</a> by causing the fungi’s cells to leak and die. It can, however, <a href="http://www.amh.hcn.net.au/view.php">cause gastrointestinal side effects and depression</a>.</p>
<p>Most nails with extensive fungal infection may still look disfigured even after 12 weeks of treatment, as the nail plate grows slowly and it takes about nine months to grow out fully. Even once the fungus is successfully eradicated, there may be long-term effects on the appearance of the nail.</p>
<p>When you go to your doctor, marking a line on the nail with a scalpel blade at the base of where the fungus starts is helpful for treatment follow-up. The patient can follow the marking as the nail grows out. If the newly grown-out nail is growing out discoloured, further treatment is required.</p>
<p>Onychomycosis patients may need to learn new, healthier habits to stop the fungus growing back. These could include protecting toes from sources of infection, wearing correctly fitting footwear, laundering socks in hot water with disinfectant, wearing protective footwear at the pool and gym, keeping nails short, using open-toed footwear and wearing shoes made of breathable material.</p>
<hr>
<p><em>Kavya E.Baby, Medical Registrar (basic physician trainee) at Canberra hospital, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/75212/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jackson Thomas received funding from government e.g. RIRDC, ACT gov, NSW Pharmacy Council, Goodwin aged care facilities, and consultant fee and/or grants from biotech companies</span></em></p><p class="fine-print"><em><span>Gregory Peterson receives funding from the Commonwealth Department of Health, National Heart Foundation, National Health & Medical Research Council, and Royal Hobart Hospital Research Foundation.</span></em></p><p class="fine-print"><em><span>Sam Kosari received funding from Capital Health Network, NSW Pharmacy Council, University of Canberra, Goodwin aged care services, ASCEPT and several consultancy projects. </span></em></p><p class="fine-print"><em><span>Julia K. Christenson 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>Although fungal nail infections are not life-threatening, they’re an important health problem because of their high prevalence and poor response to therapy.Jackson Thomas, Assistant Professor/Senior Lecturer in Pharmacy, University of CanberraGregory Peterson, Deputy Dean (Research) Faculty of Health, University of TasmaniaJulia K. Christenson, Research Assistant in Pharmacy, University of Canberra, University of CanberraSam Kosari, Assistant Professor of Pharmacy, University of CanberraLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/570082016-04-12T14:55:49Z2016-04-12T14:55:49ZGourmet meals are filled with bacteria – and they taste delicious<figure><img src="https://images.theconversation.com/files/118314/original/image-20160412-15864-1rcfgsn.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">Shutterstock</span></span></figcaption></figure><p>When diners sat down at a recent <a href="http://www.manchestersciencefestival.com/whatson/menumadebymicrobes">gourmet experience</a> held at the Harvey Nichols department store in Manchester, their food was filled with bacteria, fungus and mould. Far from being a public health hazard, this special five-course meal was designed to show how microorganisms are a fundamental part of the food we eat.</p>
<p>In general, microbes don’t have a good reputation. Yet while some cause disease and decay, the vast majority of the planet’s microorganisms are not harmful to us. In fact, they can be incredibly useful, producing alcohol, acids and other molecules that add flavour, texture and nutritional value to food, as well as helping to preserve it.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/118315/original/image-20160412-15885-1fvtqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/118315/original/image-20160412-15885-1fvtqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118315/original/image-20160412-15885-1fvtqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118315/original/image-20160412-15885-1fvtqc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118315/original/image-20160412-15885-1fvtqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118315/original/image-20160412-15885-1fvtqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118315/original/image-20160412-15885-1fvtqc.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">Baker’s yeast: keeping humanity fed for thousands of years.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Microorganisms are used to make many of the staples of our diets. Bread, cheese and wine all immediately spring to mind. But the roles of these tiny living cells is far more diverse than you might think. The term “<a href="http://www.nature.com/articles/nmicrobiol201639">artisanal food microbiology</a>” has even been coined recently to describe an emerging interest among cooks to explore the potential for microbes to create new flavours and dishes.</p>
<p>At the gourmet meal we introduced in Manchester – the first of four we are running to raise awareness of the importance of microbes in food – almost every aspect of the food had been touched in some way by microorganisms.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/118326/original/image-20160412-15871-2r746m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/118326/original/image-20160412-15871-2r746m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118326/original/image-20160412-15871-2r746m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118326/original/image-20160412-15871-2r746m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118326/original/image-20160412-15871-2r746m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118326/original/image-20160412-15871-2r746m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118326/original/image-20160412-15871-2r746m.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">Crostini canapés.</span>
<span class="attribution"><span class="source">Devin Louttit</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Sourdough crostini were the base for our delicious Welsh Rarebit canapes. Bread is produced through the <a href="https://www.exploratorium.edu/cooking/bread/bread_science.html">action of the yeast</a> <em>Saccharomyces cerevisiae</em> (baker’s yeast). This type of fungus is dormant until activated by the warm water in the dough, at which point it starts feeding on the sugars in the flour, releasing carbon dioxide that makes bread rise. Yeast adds many of the distinctive flavours and aromas we associate with bread and also produces the alcohol in beer and wine.</p>
<p><a href="http://discovermagazine.com/2003/sep/featscienceof">Sourdough bread</a> dough ferments and rises more slowly because it uses lactic acid bacteria and wild yeasts found naturally on cereal grains, rather than baker’s yeast. This produces lactic acid that gives it a tart flavour and breaks down the gluten that some people <a href="http://www.theguardian.com/lifeandstyle/2014/aug/12/rise-sourdough-bread-slow-fermented-health-benefits">struggle to digest</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/118327/original/image-20160412-15861-1hh3pm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/118327/original/image-20160412-15861-1hh3pm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118327/original/image-20160412-15861-1hh3pm8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118327/original/image-20160412-15861-1hh3pm8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118327/original/image-20160412-15861-1hh3pm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118327/original/image-20160412-15861-1hh3pm8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118327/original/image-20160412-15861-1hh3pm8.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">Sauerkraut surprise.</span>
<span class="attribution"><span class="source">Devin Louttit</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Our first course was a prosciutto platter, with apple and sultana sauerkraut (sour cabbage). The sourness comes from lactic acid, which is produced by lactic acid bacteria naturally present on the cabbage that feed on sugars released when the vegetable is sliced. These bacteria also produce vitamins including vitamin C, which is why sailors used to take sauerkraut on long voyages to <a href="http://modernfarmer.com/2014/04/magical-sour-cabbage-sauerkraut-helped-save-age-sail/">help prevent scurvy</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/118328/original/image-20160412-15883-123naeu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/118328/original/image-20160412-15883-123naeu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118328/original/image-20160412-15883-123naeu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118328/original/image-20160412-15883-123naeu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118328/original/image-20160412-15883-123naeu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118328/original/image-20160412-15883-123naeu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118328/original/image-20160412-15883-123naeu.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">Deep-fried mould.</span>
<span class="attribution"><span class="source">Devin Louttit</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>A warm salad of deep-fried Roquefort with smoked tofu followed. Cheese is made using bacteria such as <em>Lactobacillus</em> and <em>Streptococcus</em> that ferment the sugar in milk (lactose) into lactic acid. This causes a decrease in pH, preventing the growth and survival of other microbes and clotting the milk protein, turning it into solid cheese. The <a href="http://www.scientificamerican.com/article/roquefort-cheese/">blue colour</a> and distinct flavour of Roquefort comes from the mould <em>Penicillium roqueforti</em>, which – as you can guess – is related to the fungus that makes the antibiotic penicillin. Moulds are filamentous (thread-like) fungi that produce coloured spores, giving their colonies a distinctive and powdery appearance.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/118330/original/image-20160412-15861-vw6cbl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/118330/original/image-20160412-15861-vw6cbl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118330/original/image-20160412-15861-vw6cbl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118330/original/image-20160412-15861-vw6cbl.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118330/original/image-20160412-15861-vw6cbl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118330/original/image-20160412-15861-vw6cbl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118330/original/image-20160412-15861-vw6cbl.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">Merely a truffle.</span>
<span class="attribution"><span class="source">Devin Louttit</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The main course was truffled mushroom risotto and beer flatbread with rosemary. Like mushrooms, truffles are the fruiting body (spore-forming part) of fungi – organisms that are neither plants nor animals. Truffles form a symbiotic relationship (mycorrhiza) with the tree roots they grow on. This means they help the plant to gather water and minerals from the soil in exchange for sugars. Their <a href="http://www.bbc.com/future/story/20151125-why-do-truffles-taste-so-weird">pungent, musky smell</a> is thought to come <a href="http://aem.asm.org/content/81/20/6946.full">from a combination</a> of molecules given off by the truffles themselves and more microbes – the bacteria that live on them. </p>
<h2>And for dessert …</h2>
<p>The dessert consisted of pears poached in sauternes, a sweet wine that is unusual because it is made from mouldy grapes. This concentrates the grape sugar so that a significant amount remains in the wine after the traditional fermentation converts most of it to alcohol. Because of the delicious flavour this develops, the mould is known as the “<a href="http://winefolly.com/tutorial/they-call-it-noble-rot-botrytis/">Noble Rot</a>”. The scientific name for this grey mould is <em>Botrytis cinerea</em> and it is closely related to species of <em>Penicillium</em>. It produces a chemical aroma compound, phenylacetaldehyde, which is also commonly found in buckwheat and milk chocolate.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/118331/original/image-20160412-15864-iutbt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/118331/original/image-20160412-15864-iutbt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/118331/original/image-20160412-15864-iutbt9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/118331/original/image-20160412-15864-iutbt9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/118331/original/image-20160412-15864-iutbt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/118331/original/image-20160412-15864-iutbt9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/118331/original/image-20160412-15864-iutbt9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">From slime to sublime.</span>
<span class="attribution"><span class="source">Devin Louttit</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We finished our gourmet microbe meal with chocolate tart with framboise beer sauce, followed by coffee and chocolate petit fours. Both chocolate and coffee beans, which are actually seeds, go through a fermentation process that is used to break down the slimy “mucilage” coating that holds the seeds in the pod and to develop delicious and important chemical compounds. <a href="http://accounts.smccd.edu/case/chocolate.html">A series of bacteria</a>, yeasts and moulds are used to develop these flavour compounds, natural chemicals that we enjoy for their aroma and flavour.</p>
<p>Although many of these food fermentations are thousands of years old, chefs at experimental restaurants such as <a href="http://www.theverge.com/2016/3/29/11320596/chefs-fermentation-microbe-flavor-cooking-nature-microbiology">noma in Copenhagen</a> are still playing with microbes to produce new flavours. There is even a <a href="http://fermentationfest.com">growing fermentation community</a> of professional and amateur microbiologists who can cook up new kinds of acid to help make your new dish taste just right. So when you’re looking for a special new ingredient, perhaps you should turn to some of the oldest lifeforms on the planet.</p><img src="https://counter.theconversation.com/content/57008/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>How microbes are the key ingredients when it comes to concocting a gourmet menu.Joanna Verran, Professor of microbiology, Manchester Metropolitan UniversityMike Dempsey, Head of Faculty Research Degrees, Manchester Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/547432016-02-16T18:24:02Z2016-02-16T18:24:02ZHidden housemates: meet the moulds growing in your home<figure><img src="https://images.theconversation.com/files/111575/original/image-20160215-8211-15wm44y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Your home is full of fungi. </span> <span class="attribution"><span class="source">Mould image from www.shutterstock.com</span></span></figcaption></figure><p><em>Home alone? Hardly. Our homes are positively swarming with creatures of all kinds. In our new series, we’ll be profiling the “hidden housemates” that live with us.</em> </p>
<p>Our offices and homes are full of airborne spores from fungi, and for the most part we never even notice them.</p>
<p>Whether you like to think about it or not, you’re covered in microorganisms. Absolutely teeming with them from head to toe. Your body is covered and filled with bacteria called commensals, which inhabit the microscopic valleys of your skin and recesses of your gut. These organisms for the most part never cause you any harm, and in fact protect you from being colonised by disease-causing organisms. </p>
<p>In the same way that you’re a walking zoo of microbes, the world around you is peppered with invisible microorganisms. </p>
<h2>Ancient relationship</h2>
<p>This isn’t a new relationship though. Humans have been cohabiting with fungi for a very long time. </p>
<p>Ancient Egyptian bakers and brewers were harnessing natural yeasts more than <a href="http://search.proquest.com/docview/213552171?pq-origsite=gscholar">4,000 years ago</a>, but it was only in the 1850s that we realised it was microbes that were responsible for <a href="http://onlinelibrary.wiley.com/doi/10.1002/1097-0061(20000615)16:8%3C755::AID-YEA587%3E3.0.CO;2-4/full">leavening bread and making alcohol</a>.</p>
<p>We’ve also known for a very long time that unpreserved foods spoil, growing conspicuously fuzzy tufts of blue and green mould. The kinds of moulds that make our bread and make forgotten oranges go fluffy are really the weeds of the fungal world.</p>
<p><em>Penicillium</em> (this is the same fungus involved in the discovery of the first antibiotics, but that’s another story) and <em>Aspergillus</em> are the microscopic equivalent of soursobs and dandelions, and look fairly similar in a lot of ways. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/111592/original/image-20160216-6548-1fbxe2z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111592/original/image-20160216-6548-1fbxe2z.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111592/original/image-20160216-6548-1fbxe2z.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111592/original/image-20160216-6548-1fbxe2z.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111592/original/image-20160216-6548-1fbxe2z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111592/original/image-20160216-6548-1fbxe2z.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111592/original/image-20160216-6548-1fbxe2z.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Aspergillus niger, the fungal dandelion.</span>
<span class="attribution"><span class="source">Michael Taylor</span></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/111613/original/image-20160216-8211-e8jows.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111613/original/image-20160216-8211-e8jows.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111613/original/image-20160216-8211-e8jows.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111613/original/image-20160216-8211-e8jows.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111613/original/image-20160216-8211-e8jows.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111613/original/image-20160216-8211-e8jows.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111613/original/image-20160216-8211-e8jows.png?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">Penicillium, the source of the antibiotic penicillin.</span>
<span class="attribution"><span class="source">Michael Taylor</span></span>
</figcaption>
</figure>
<p>Walk through any park, or into any building the world over and you’ll probably be picking up spores from <em>Penicillium</em> and <em>Aspergillus</em>; up to a <a href="http://ibe.sagepub.com/content/23/7/1002.short">several hundred per cubic metre of air is normal</a>. In fact when you’re looking at indoor fungi, if you don’t find these two floating around you often question if you’ve taken your samples correctly.</p>
<h2>Is your house ‘killing you’?</h2>
<p>Indoor airborne fungi have become implicated in “<a href="https://en.wikipedia.org/wiki/Sick_building_syndrome">sick building syndrome</a>” and claims that our homes are “<a href="https://www.youtube.com/watch?v=2q6OqA7_Etc">killing us</a>”. </p>
<p>There is some sense mixed in with the scare here. These kinds of organisms can colonise our houses and <a href="https://theconversation.com/health-check-how-does-household-mould-affect-your-health-48341">cause serious illness</a> but it’s unlikely that you’re in imminent danger. </p>
<p>Mould becomes a problem when there is moisture, or the inability for it to escape. After large rainfall or flood events, porous materials in buildings like wood, insulation, carpet and furnishings absorb a lot of water. </p>
<p>This water can then support the growth of fungi and fill cavities and hidden areas with very humid and stagnant air – perfect conditions for problem moulds such as <em>Stachybotrys</em>, the <a href="http://toxsci.oxfordjournals.org/content/104/1/4.long">toxic black mould</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/111612/original/image-20160216-8211-1j2jqed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111612/original/image-20160216-8211-1j2jqed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111612/original/image-20160216-8211-1j2jqed.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111612/original/image-20160216-8211-1j2jqed.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111612/original/image-20160216-8211-1j2jqed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111612/original/image-20160216-8211-1j2jqed.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111612/original/image-20160216-8211-1j2jqed.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">Stachybotrys, or Black mould.</span>
<span class="attribution"><span class="source">Unknown</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111617/original/image-20160216-22545-1t6zr4u.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">If your bathroom is looking like this, you may have a problem…</span>
<span class="attribution"><span class="source">Black mould image from www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>Most of the time though the fungi that turn up after water damage shouldn’t poison you or cause infection, but will probably smell musty and cause allergy-like symptoms until the problem is fixed. </p>
<p>In many cases fixing the root cause may be relatively simple, with the first step always being to ensure that whatever caused the water to accumulate is fixed and any excess moisture is dried out. Non-porous surfaces are often simply able to be wiped clean of all visible mould with a detergent or cleaning spray. </p>
<p>Soft furnishings, clothes and carpets should be thoroughly vacuumed and washed if possible, or thrown out if extensively contaminated. Porous surfaces are increasingly more difficult as wiping the surface clean may not actually remove the mould and will likely need to be replaced to fully solve the problem. Extensively damaged homes after a flood may be beyond remediation, and any clean-up operations on this scale should always involve a professional.</p>
<p>But it’s not just leaky roofs that encourage fungi to come indoors though, our push towards ultra-efficient green buildings can <a href="http://link.springer.com/article/10.1023/A:1015592224368">cause similar problems</a>. </p>
<p>To reduce energy costs, we often design our air-conditioning systems to recycle as much of the indoor air as possible, which over the course of the day can slowly push up carbon dioxide and moisture in the air. </p>
<p>If this isn’t removed, it can leave you feeling sleepy and the air feeling heavy whilst providing an opportunity for fungi to take over.</p>
<h2>The fungal garden in your home</h2>
<p>We’re often told to aim for a lifestyle with “balance”. The same is true for our microscopic housemates. </p>
<p>If you end up with one single species dominating <a href="http://www.who.int/indoorair/publications/7989289041683/en/">you may have a problem</a>. On the other hand a mixture of species shows that everything is relatively in order and is an indicator of a healthy environment.</p>
<p>The mixture of airborne fungi does change from place to place, but not as dramatically as you’d expect. The same specimens tend to turn up the world over: <em>Penicillium</em>, <em>Aspergillus</em> and <em>Cladosporium</em>, alongside a handful of other common fungi. </p>
<p>If you live near agricultural pastures, you may find a greater abundance of plant pathogens like <em>Alternaria</em>, <em>Stemphylium</em> and <em>Fusarium</em>. The species may change if you’re in different regions of the world, but overall your lungs probably contain similar spores to your relatives in Spain or Japan. </p>
<p>If you live in California’s San Joaquin Valley, however, you are in the unlucky position of being tens of thousands of times more likely to be exposed to infectious spores from the fungi <a href="http://jcm.asm.org/content/45/1/26.short"><em>Coccidioides immitis</em></a>, which cause the otherwise relatively rare condition of fungal pneumonia. </p>
<p>But if it makes you uncomfortable to think about the invisible world pulsing with life around you, relax. Generally a healthy mixture of fungi can indicate a healthy home, and I promise you that life is better with fungi in it than without. </p>
<p><em>Are you a researcher with an idea for a “hidden housemates” story? <a href="mailto:james.whitmore@theconversation.edu.au">Get in touch</a></em>.</p><img src="https://counter.theconversation.com/content/54743/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Taylor 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>Moulds and fungi have been living with us for thousands of years - you just might not think about them until they become a problem.Michael Taylor, Lecturer, School of the Environment, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/483412015-11-02T03:23:11Z2015-11-02T03:23:11ZHealth Check: how does household mould affect your health?<figure><img src="https://images.theconversation.com/files/99758/original/image-20151027-18454-1mtjh7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A considerable proportion of childhood asthma is attributable to exposure to indoor dampness and mould. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/70237334@N04/6379728773/">carlpenergy/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Exposure to harmful agents inside the home can have profound effects on our health. After all, we spend an average of <a href="http://www.ncbi.nlm.nih.gov/pubmed/16078638">16 hours a day</a> at home – and even more when aged under seven and over 64. </p>
<p>Mould accumulates in damp and poorly ventilated buildings. Inhaling mould fragments or spores can inflame the airways, causing nasal congestion, wheezing, chest tightness, coughing and throat irritation. </p>
<p>Prolonged exposure to high levels of indoor dampness <a href="http://ehp.niehs.nih.gov/1002410/">can reduce lung function</a> and cause chronic health problems such as asthma. Those who already suffer from asthma and allergies are more likely to have <a href="http://ehp.niehs.nih.gov/1002410/">more severe symptoms</a> when exposed.</p>
<p>According to the World Health Organization (<a href="http://www.who.int/en/">WHO</a>), a <a href="http://www.euro.who.int/__data/assets/pdf_file/0003/142077/e95004.pdf">considerable proportion</a> of the world’s <a href="http://journal.publications.chestnet.org/article.aspx?articleid=1210781">300 million cases</a> of childhood asthma is attributable to exposure to indoor dampness and mould. </p>
<p>People who live in damp and mouldy homes are also at increased risk of <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1994167/">depression</a> which, in turn, may <a href="http://www.ncbi.nlm.nih.gov/pubmed/21532014">increase the risk</a> of respiratory symptoms and <a href="http://ehp.niehs.nih.gov/1002410/">asthma</a>. </p>
<p>The most infamous type of mould is “black mould” (<em>Stachybotrys chartarum</em>), which can grow on water-damaged building materials and produce toxic spores. In 1994, it was linked to a <a href="http://jama.jamanetwork.com/article.aspx?articleid=192616">serious respiratory illness</a> after ten children experienced idiopathic pulmonary haemosiderosis (bleeding from the lung) and one subsequently died.</p>
<p>But despite significant media interest and public concern, a causal link was <a href="http://www.cdc.gov/mold/stachy.htm#Q8">never established</a>. </p>
<h2>Who is at risk?</h2>
<p>It’s commonly assumed that mould causes the health problems described above, though the evidence for this is generally weaker than for dampness itself. This may be related to the fact that scientists are still struggling to accurately measure indoor mould exposures.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/99760/original/image-20151027-18454-mo0872.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/99760/original/image-20151027-18454-mo0872.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/99760/original/image-20151027-18454-mo0872.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/99760/original/image-20151027-18454-mo0872.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/99760/original/image-20151027-18454-mo0872.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/99760/original/image-20151027-18454-mo0872.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/99760/original/image-20151027-18454-mo0872.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Indoor dampness and mould may not only aggravate pre-existing respiratory conditions, there is also (limited) evidence it may cause new symptoms.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/30912734@N04/3631079012/">KristyFaith/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>The WHO <a href="http://www.euro.who.int/__data/assets/pdf_file/0003/142077/e95004.pdf">estimates</a> that in cold climates, 15% of dwellings have signs of dampness and 5% have signs of mould problems. In warm climates, the estimates are 20% for dampness and 25% for mould. </p>
<p>Since dampness is more likely to occur in houses that are overcrowded and lack appropriate heating, ventilation and insulation, the prevalence of damp indoor problems in low-income communities and rental accommodation can be substantially higher.</p>
<p>Climate change and its effects on the weather (storms, heavy rainfall and floods) are likely to <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4499913/">further increase</a> the proportion of buildings with damp problems. </p>
<h2>What can you do?</h2>
<p>In addition to visible mould, other signs of damp problems may include: mould odour, water stains, frequent condensation, peeling or cracked paint or wall paper, damp basement, and standing water under or around the house.</p>
<p>No safe levels of indoor dampness and or mould have been defined. So health-based standards or guidelines do not exist. </p>
<p>Nonetheless, there are several practicable measures you can take to prevent or minimise indoor mould. These include adequately heating and, in colder climates, insulating your home to reduce air humidity levels and condensation. </p>
<p>Install and use appropriate ventilation, particularly in wet areas or areas where water vapour may be emitted, such as bathrooms, laundries and kitchen areas.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/99759/original/image-20151027-18424-64ts54.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/99759/original/image-20151027-18424-64ts54.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/99759/original/image-20151027-18424-64ts54.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/99759/original/image-20151027-18424-64ts54.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/99759/original/image-20151027-18424-64ts54.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/99759/original/image-20151027-18424-64ts54.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/99759/original/image-20151027-18424-64ts54.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">Don’t just clean the mould; address the source of the dampness.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/sermoa/3167243815/">aimee rivers/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>It’s also critical to avoid water leaks by controlling and maintaining rain and surface water drainage. Where holes are created in the roof or walls to allow skylights, windows, doors, pipes or other structures to be fitted, make sure these are watertight. </p>
<p>If you find visible mould in your home, remove the mould and identify and address the cause of the excess moisture. Clean hard surfaces using soap and water or, if mould growth is persistent, a bleach solution could be used. You may need to throw away absorbent materials such as carpets, depending on the level of contamination. </p>
<p>In case of extensive mould damage, you may need to call on commercial mould remediation services. </p>
<p>Although those with pre-existing allergies or asthma are at greater risks, mould can also cause health effects in otherwise healthy people. So measures to prevent or reduce mould exposure are important to everyone.</p>
<p>Some regions may require stricter regulations and building codes to prevent dampness and mould. </p>
<p>Damp problems are particularly prevalent in rental houses, often due to poor maintenance. So regulators should also consider a periodic inspection system (or “warrant of fitness”) to ensure minimal housing standards are met.</p><img src="https://counter.theconversation.com/content/48341/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jeroen Douwes receives funding from the New Zealand Health Research Council. </span></em></p>Exposure to harmful agents inside the home can have profound effects on our health. After all, we spend an average of 16 hours a day at home – and even more when aged under seven and over 64.Jeroen Douwes, Professor of Public Health; Director, Centre for Public Health Research, Massey UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/232572014-02-19T03:39:19Z2014-02-19T03:39:19ZIs your home harming you? Asthma, allergies and indoor mould<figure><img src="https://images.theconversation.com/files/41741/original/sqtks4f4-1392684611.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Indoor mould can increase the risk of active asthma.</span> <span class="attribution"><span class="source">Meg's my name/Flickr</span></span></figcaption></figure><p>It is hard to escape indoor mould. It is most commonly found in the wet areas of the home, especially the bathroom and the kitchen, but it can grow anywhere. We all agree that it’s unsightly, but the bigger problem is it can harm your lungs.</p>
<p>According to the findings from our study published recently in the journal <a href="http://onlinelibrary.wiley.com/doi/10.1111/resp.12245/abstract">Respirology</a>, indoor mould can increase the risk of active asthma, even in those who don’t have an allergy to mould. </p>
<p>The good news is that getting rid of the culprit may reduce the incidence of asthma.</p>
<h2>Asthma in middle age</h2>
<p>Our research involved the participants in the <a href="http://www.tahs.com.au/">Tasmanian Longitudinal Health Study</a>, the world’s largest and longest-running population-based study of lung health. This study started in 1968 when 8,583 seven-year-old Tasmanian school-children were enrolled by their parents. </p>
<p>Now in middle age, these original seven-year-olds have been followed at intervals, most recently in 2004-06. At that follow-up, we traced 5,729 participants to determine whether they had asthma or asthma-linked symptoms and the presence of visible mould and other airborne pollutants in their homes. We then allergy tested a subset of 1,383 participants. </p>
<p>When we analysed the data, we found the overall risk of active asthma was increased by 26% in those who had visible mould in the home in the last 12 months. </p>
<p>We also found that the more rooms in the house affected by mould, the greater the risk of active asthma. In other words, there was evidence that the “dose” of mould influenced the risk of active asthma. </p>
<p>These are novel findings, adding to the existing body of knowledge on what might cause asthma.</p>
<h2>Identifying the cause</h2>
<p>All asthma is not necessarily the same. A lot of asthma is “allergic”, developing in those who test positive to a skin test for a variety of possible allergens. This applies particularly to children and teenagers. </p>
<p>But asthma can also be “non-allergic”, developing in those with negative allergy skin tests. This type of asthma tends to occur more in adults, and interestingly, more often in women than men.</p>
<p>A considerable amount of asthma research has been done with children and adolescents, and in this age group, the risk for allergic asthma associated with mould sensitivity is well known. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/41742/original/znzfnmch-1392684928.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/41742/original/znzfnmch-1392684928.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/41742/original/znzfnmch-1392684928.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/41742/original/znzfnmch-1392684928.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/41742/original/znzfnmch-1392684928.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/41742/original/znzfnmch-1392684928.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/41742/original/znzfnmch-1392684928.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Allergic asthma generally develops in childhood.</span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/30912734@N04/3631079012/sizes/l/">KristyFaith</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>But not so well known is that mould exposure can be associated with non-allergic asthma, as our study showed. Our finding that this association was stronger in men than women was a little unexpected, and of considerable interest. </p>
<p>Much of the problem with mould lies with its ability to induce an allergic response in persons genetically predisposed – and mould allergy is common. In our study, 35% of participants reported mould in the home in the last 12 months and 13% of those skin tested had mould allergy. <a href="http://www.karger.com/Journal/Issue/233726">Other studies</a> have found mould allergy in up to 24% of the general population and up to 80% among asthmatics. </p>
<p>One of the problems in trying to decide if mould has a causal role in asthma is that mould allergy often occurs in common with allergies to other asthma-related agents, particularly <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/House_dust_mite">house dust mites</a>. This co-existence makes it difficult to tease out the role of any single agent. </p>
<p>In addition, mould and dampness go hand in hand, and excessive indoor dampness in its own right is a known risk factor for asthma. Given the potential for climate change to lead to more extreme weather and increase the risk of flooding, indoor dampness may well become more of a problem in the future. </p>
<p>Allergic sensitisation is not the only mechanism by which mould can affect lung health. Mould produces various <a href="http://www.who.int/indoorair/publications/7989289041683/en/">toxic and chemical substances</a> including <a href="https://theconversation.com/health-check-is-it-safe-to-cut-mould-off-food-21382">mycotoxins</a>, <a href="http://www.webmd.com/vitamins-supplements/ingredientmono-1041-BETA%20GLUCANS.aspx?activeIngredientId=1041&activeIngredientName=BETA%20GLUCANS">beta-glucans</a>, <a href="http://www.britannica.com/EBchecked/topic/191309/ergosterol">ergosterol</a> and volatile organic compounds that can have a direct inflammatory effect on the lining of the airways. Such substances don’t depend on inducing an allergic response for their effect on the lungs. </p>
<p>To complicate matters further, how the lungs respond to such agents depends on the “dose” to which an individual is exposed and on the variability in the way different people respond to the same lung stressor.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/41743/original/xwnn3mb8-1392685014.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/41743/original/xwnn3mb8-1392685014.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/41743/original/xwnn3mb8-1392685014.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/41743/original/xwnn3mb8-1392685014.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/41743/original/xwnn3mb8-1392685014.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/41743/original/xwnn3mb8-1392685014.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/41743/original/xwnn3mb8-1392685014.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">Mould and dampness go hand in hand.</span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/22912005@N06/5632578140/sizes/l/">Abby flat-coat/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Reducing the risk</h2>
<p><a href="http://www.cdc.gov/mold/faqs.htm">Health authorities</a> suggest that removing mould from the home can make a difference to people susceptible to asthma.</p>
<p>There are <a href="http://www.public.health.wa.gov.au/cproot/2887/2/Mould%20Fact%20Sheet.pdf">several treatments</a> for mould, such as Tea Tree Oil and fermented vinegar solutions. It’s best avoid dry brushes (which can spread mould further) and bleach, which doesn’t kill mould (it merely bleaches the colour so it looks like it has disappeared). </p>
<p>It’s also important to <a href="http://www.public.health.wa.gov.au/cproot/2887/2/Mould%20Fact%20Sheet.pdf">address the causes of mould</a>. This comes down to lessening indoor humidity and dampness by improving home ventilation and heating. This will be more difficult in older houses, which may have ongoing problems with dampness because or broken roof tiles, poor cavity wall ventilation and rising damp. </p>
<p>Finally, all asthma sufferers should routinely use their preventer and reliever medications as prescribed for asthma control and symptom relief.</p><img src="https://counter.theconversation.com/content/23257/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Burgess receives funding from NHMRC Australia through the Centre for Research Excellence in Chronic Resplratory Disease.</span></em></p>It is hard to escape indoor mould. It is most commonly found in the wet areas of the home, especially the bathroom and the kitchen, but it can grow anywhere. We all agree that it’s unsightly, but the bigger…John Burgess, Research Fellow, CRE for Chronic Respiratory Disease, Centre for Epidemiology and Biostatistics , The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/119352013-02-06T00:00:13Z2013-02-06T00:00:13ZQueenslanders at risk from mould as flood clean-up continues<figure><img src="https://images.theconversation.com/files/19961/original/5dfffdyn-1360038990.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Damp conditions are linked to respiratory problems, but mould may not be the cause.</span> <span class="attribution"><span class="source">AAP/Kym Agius</span></span></figcaption></figure><p>The floods have come and gone in Queensland and in their wake are heartbreak, devastation and months, if not years, of clean-up and rebuilding. Those affected now face a hidden risk to their health from water-damaged, damp and mouldy buildings. </p>
<p>There is a large body of scientific evidence that supports an association between various health problems and damp, mouldy environments. This evidence was examined and summarised in a <a href="http://www.iom.edu/Reports/2004/Damp-Indoor-Spaces-and-Health.aspx">2004 Institute of Medicine report</a> and a <a href="http://www.euro.who.int/en/what-we-do/health-topics/environment-and-health/air-quality/publications/2009/who-guidelines-for-indoor-air-quality-dampness-and-mould.-executive-summary/who-guidelines-for-indoor-air-quality-dampness-and-mould">2009 World Health Organisation report</a>. The message is clear: damp home environments are associated with respiratory problems including asthma, coughs, respiratory infections and upper airway problems.</p>
<p>But the cause-and-effect proof for this association is lacking. In other words, while damp living environments is associated with increased risk of a number of respiratory symptoms, the reason the risk increases is unknown. It’s tempting to conclude that mould is the cause, as mould grows in damp conditions and, in many cases, visible mould is reported in damp housing.</p>
<h2>Mould exposure and health risks</h2>
<p>Moulds are complex organisms that are difficult to quantify reliably. Mould is associated with two broad categories of human illness: infectious diseases and non-infectious illness, usually allergy-related conditions.</p>
<p>Invasive (infection-causing) illness caused by mould is uncommon and usually occurs in people whose immune systems are compromised. There was no measurable increase in invasive mould infection reported in New Orleans after Hurricane Katrina, perhaps the best studied model for post-flood health effects.</p>
<p>Allergic sensitivity to various moulds, detected by skin and blood tests, is associated with exacerbation of asthma. There’s <a href="http://www.iom.edu/Reports/2004/Damp-Indoor-Spaces-and-Health.aspx">evidence linking</a> asthma exacerbation in sensitised individuals to damp indoor environments, but not enough evidence to suggest that such environments <em>cause</em> asthma.</p>
<p><a href="http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001168/">Hypersensitivity pneumonitis</a>, or inflammation of the lung, is another immune-mediated condition <a href="http://www.ncbi.nlm.nih.gov/pubmed/17605960">caused by mould exposure</a>.</p>
<p>There are non-immune effects of mould exposure and these are mostly irritant in nature. Exposure to <a href="http://www.ncbi.nlm.nih.gov/pubmed/10510522">high levels of (1-3)B-D-glucan</a>, a chemical found in mould cell walls, has been linked to chronic cough, throat irritation and irritation of upper respiratory tract.</p>
<h2>Damage from damp</h2>
<p>Along with mould, numerous bacteria and amoeba species may flourish in damp housing, and there may be synergistic effects between them and other toxins, an area open to further research.</p>
<p>Damp buildings often have raised levels of <a href="http://www.cdc.gov/niosh/nas/rdrp/appendices/chapter4/a4-39.pdf">endotoxins</a> (toxins within bacteria). Endotoxin <a href="http://www.sciencedirect.com/science/article/pii/S0091674902085688">has been associated</a> with animal exposure and farm environments, and may protect against the development of allergic conditions. But in association with other dampness-related factors, it may have negative effects.</p>
<p>There are also other potentially harmful factors to consider. Flooding and dampness may damage building materials and furnishings, causing them to release toxic chemicals such as formaldehyde from composite wood products and plasticizers (2-ethyl-1-hexanol) from vinyl flooring.</p>
<p>As you can see, there are many factors to consider when attempting to establish causal relationships between dampness and respiratory illness. This explains why proof of cause and effect has been difficult to obtain.</p>
<h2>Lessons from Hurricane Katrina</h2>
<p>The devastation of New Orleans caused by Hurricanes Katrina and Rita left communities homeless and entire suburbs destroyed. The clean-up was massive, taking many people months and years and exposing them to damp, mouldy environments. Many of those involved in restoration developed a chronic cough, which was dubbed the “<a href="http://new.dhh.louisiana.gov/assets/oph/Center-PHCH/Center-CH/stepi/specialstudies/KatrinaCoughReport.pdf">Katrina cough</a>” and became widespread after the hurricanes. It was attributed to irritant phenomena.</p>
<p>A number of scientific studies monitored and measured the health effects of long-term exposure to damp, mouldy environments. Monitoring demonstrated high mould and spore levels in the wake of Katrina, but the clinical studies performed at the time did not show the anticipated impact on health.</p>
<p>A <a href="http://new.dhh.louisiana.gov/assets/oph/Center-PHCH/Center-CH/stepi/specialstudies/KatrinaCoughReport.pdf">2006 study</a> looking at 50,000 visits to emergency departments and medical clinics measured presentations for cough, wheeze, sinus drip, sore throat and chest congestion and found no increase in respiratory presentations compared to other parts of the country. But those with a history of asthma were more likely to experience symptoms because of mould and dust exposure.</p>
<p>Problems with sampling, bias in reporting and use of qualitative assessment have been cited as possible reasons for a lack of association in these studies.</p>
<h2>Challenges ahead</h2>
<p>Chronic allergic and non-allergic respiratory diseases are global problems that extract enormous human, economic and social costs. It’s estimated that <a href="http://www.iom.edu/Reports/2004/Damp-Indoor-Spaces-and-Health.aspx">20% to 50% of all building stock</a> in the United States and Europe have problems with damp. If the two are linked, then removing pollutants from housing and better planning and building codes must become a priority. The challenge to the scientific community is to clarify the components of dampness that are key, how to measure them and how to effect change.</p>
<p>As Queensland cleans up from the floods, it’s important that asthmatics wear good-quality face masks while handling mouldy things. If someone is immunosuppressed (for example, receiving chemotherapy for cancer), it’s best for them to stay out of the environment or wear proper respiratory protection.</p>
<p>Where possible, infants and young children shouldn’t be continuously exposed to mouldy environments. Most important for those in flood-affected areas is cleaning up and restoring a dry living environment as quickly as possible.</p><img src="https://counter.theconversation.com/content/11935/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Connie Katelaris 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 floods have come and gone in Queensland and in their wake are heartbreak, devastation and months, if not years, of clean-up and rebuilding. Those affected now face a hidden risk to their health from…Connie Katelaris, Professor of Immunology and Allergy, UWAS & Head of Unit, South Western Sydney Local Health DistrictLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/100152012-10-08T19:21:10Z2012-10-08T19:21:10ZThe brainless slime mould that remembers where it’s been<figure><img src="https://images.theconversation.com/files/16266/original/p96jgrd4-1349654786.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1602%2C1134&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How do you remember where you've been if you don't have a brain?</span> <span class="attribution"><span class="source">Tanya Latty</span></span></figcaption></figure><p>We humans use our large brains to make and store maps of our environment; maps we then use everyday for getting around and for recalling where we’ve been. But we are nothing special – many other animals are capable of using spatial memory to make life easier.</p>
<p>And while many animals have this ability, spatial memory has so far only been described in animals with brains to store the memories in. Until now. </p>
<p>My colleagues and I – from the University of Sydney and the Paul Sabatier Université in Toulouse – found that the unicellular slime mould <a href="http://en.wikipedia.org/wiki/Physarum_polycephalum"><em>Physarum polycephalum</em></a>, which lacks a brain or even any semblance of a nervous system, uses an ingenious mechanism to remember where it has been, and to escape from difficult situations. Our findings are <a href="http://intl.pnas.org/content/early/2012/10/04/1215037109.abstract">published today in PNAS</a>.</p>
<h2>Introducing <em>Physarum</em></h2>
<p>The slime mould <em>Physarum</em> is a large, blob-like cell that moves around like an <a href="http://en.wikipedia.org/wiki/Amoeba">amoeba</a>. The whole organism is made up of bits of pulsating tissue, which are constantly expanding and contracting, using a similar mechanism to our own muscle cells.</p>
<p>Each part of the slime mould changes the speed at which it pulsates according to what it can sense in the environment around it – food, light or heat, for instance. These stimuli are detected by chemical receptors on the cell’s surface.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=628&fit=crop&dpr=1 600w, https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=628&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=628&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=789&fit=crop&dpr=1 754w, https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=789&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/16267/original/tpdx5qpb-1349654943.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=789&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 slime mould ventures out from its point of origin.</span>
<span class="attribution"><span class="source">Tanya Latty</span></span>
</figcaption>
</figure>
<p>These pulsating parts are also influenced by the throbbing of their neighbours within the cell, which means the parts can communicate with one another, to pass information through the organism about what is happening in the external environment. The different speeds of contraction directly influence which direction the cell will then move in.</p>
<p>In this way, a seemingly simple slime mould is really a complex, collective system, which behaves much like an ant colony or a school of fish.</p>
<h2>Getting around</h2>
<p>The brainless slime mould leaves a trail of slime behind it everywhere it goes, which it can then detect later to recognise areas it has already been. The organism prefers to avoid previously explored areas, to prevent wasting time in its search for food.</p>
<p>In essence the slime mould is memorising where it has been, storing this memory in the external environment and recalling the information when it later touches the slime-coated area.</p>
<h2>What we did</h2>
<p>By forcing the slime mould into a U-shaped obstacle, which we placed between the creature and a sugary food source it was drawn to, we found the slime mould used its spatial memory system to help navigate its way out of the obstacle to reach the food.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=603&fit=crop&dpr=1 600w, https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=603&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=603&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=757&fit=crop&dpr=1 754w, https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=757&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/16272/original/y62p47hk-1349662842.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=757&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 slime mould (yellow blob) was placed at one end of a petri dish with the sugary food source (black smudge) placed at the other end. The U-shaped trap was setup in between.</span>
<span class="attribution"><span class="source">Chris R. Reid</span></span>
</figcaption>
</figure>
<p>Some 96% of the test subjects in our experiment successfully navigated the trap and reached the goal within the 120 hour time limit (slime mould moves slowly!), with the average slime mould taking 57 hours to solve the problem.</p>
<p>When we disabled the creature’s ability to use its memory – by coating the whole environment in slime to mask its own trail – only 33% of the slime moulds reached the goal within the time limit. The 33% that did finish took much longer to do so, averaging 75 hours.</p>
<p>Without the benefit of memory, the slime mould spent almost ten times longer pointlessly re-exploring areas it had already been. So the organism relies on its externalised spatial memory for navigating through complex environments.</p>
<h2>More than mould</h2>
<p>The kind of U-shaped trap we used in our experiment has been <a href="http://bit.ly/R4XHbN">used in the past</a> to test the abilities of robots that navigate on their own.</p>
<p>Normally we hear about how nature inspires engineering and design, for instance how studying the <a href="http://www.stle.org/assets/news/document/TechBeat_TLT_12-08.pdf">flippers of humpback whales led to better blades for wind turbines</a>, or how the <a href="http://www.todayifoundout.com/index.php/2011/09/velcro-was-modeled-after-burrs-of-the-burdock-plant-that-stuck-to-velcros-inventors-pants-after-a-hunting-trip/">hooks on burdock seeds inspired the birth of Velcro</a>. </p>
<p>But our findings are a neat example of the reverse: how engineering studies (i.e. the use of the U-shaped trap) can sometimes influence our understanding of the natural world.</p>
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<iframe src="https://player.vimeo.com/video/50950272" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
</figure>
<p></p><figcaption>By avoiding areas it’s already been in, the slime mould finds its way out of the U-shaped trap and over to the food source. <span>Tanya Latty</span></figcaption><p></p>
<p>Leaving an externalised reminder of where you have been is a phenomenon behavioural ecologists call <a href="http://www.jstor.org/discover/10.2307/5724?uid=3737536&uid=2129&uid=2&uid=70&uid=4&sid=21101122656113">“patch-marking”</a>. And, of course, it’s not just slime mould that does this.</p>
<p>After depleting the nectar from a flower, honeybees will <a href="http://www.jstor.org/discover/10.2307/4219856?uid=3737536&uid=2129&uid=2&uid=70&uid=4&sid=21101122656113">leave a chemical mark</a> telling them not to bother returning there until the flower has replenished its nectar reserves. </p>
<p>Similarly, wolves, foxes and chipmunks will all <a href="http://www.jstor.org/discover/10.2307/4534102?uid=3737536&uid=2129&uid=2&uid=70&uid=4&sid=21101122656113">leave a chemical reminder</a> in the form of urine on sites where they have just dug up stored food, so they can remember which stores have been depleted, and avoid searching in those areas later on.</p>
<p>But while many creatures are able to use spatial memory, our study is the first to demonstrate this ability in a creature without a brain.</p>
<p>Our study is also the first piece of evidence to support a previously untested theory that an externalised memory could have been used by primitive organisms in the distant past to solve problems tackled by complex brains like ours today.</p>
<p>Better still, this primitive memory system could have been the first step in the evolution of a more complex memory system in organisms with brains, we humans included.</p><img src="https://counter.theconversation.com/content/10015/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris R. Reid 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>We humans use our large brains to make and store maps of our environment; maps we then use everyday for getting around and for recalling where we’ve been. But we are nothing special – many other animals…Chris R. Reid, ARC Future Fellow, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/59282012-03-20T19:33:13Z2012-03-20T19:33:13ZFloods herald creeping problem of mould and growing health risks<figure><img src="https://images.theconversation.com/files/8801/original/z4svczm2-1332224112.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Flooded houses are seen at night in Gundagai, NSW earlier this month.</span> <span class="attribution"><span class="source">AAP Image/Lukas Coch</span></span></figcaption></figure><p>The past five years have seen record rainfall and flooding in many towns and cities across eastern Australia. The floods themselves are dangerous, but so are the health hazards associated with the indoor dampness that follows and, more specifically, the excessive mould it encourages. </p>
<p>A lot of indoor mould growth resulted from <a href="http://www.katrina.noaa.gov/">Hurricane Katrina</a> and the flooding of homes in New Orleans in 2005. Concern for the health of workers involved in the clean-up led the United States <a href="http://www.cdc.gov/">Centres for Disease Control and Prevention</a> to <a href="http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5508a1.htm">advise that</a> “excessive exposure to mould-contaminated materials can cause health effects in susceptible persons regardless of the type of mould or extent of contamination”.</p>
<p>Two major reports by the United States <a href="http://www.iom.edu/">Institute of Medicine (IOM)</a> (from <a href="http://iom.edu/Reports/2000/Clearing-the-Air-Asthma-and-Indoor-Air-Exposures.aspx">2000</a> and <a href="http://www.iom.edu/Reports/2004/Damp-Indoor-Spaces-and-Health.aspx">2004</a>) concluded that there was sufficient evidence of an association between mould and upper respiratory tract symptoms, wheezing, coughing and asthma symptoms in sensitised asthmatic individuals. </p>
<p>Although there’s a <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0668.2007.00475.x/full">strong body of evidence</a> linking indoor dampness to asthma attacks, the exact role of moulds has been difficult to determine because it hasn’t been easy to disentangle mould exposures from the many other exposures that occur in damp indoor environments. </p>
<p>Persistent dampness causes building materials to decompose and release volatile organic compounds (VOCs), such as phthalates, which are released from wet vinyl floors. Mould exposure is complex because residents are exposed to both living and dead spores, and to mould fragments as well as mould products, such as allergens, cell wall chemicals, toxins, and microbial VOCs.</p>
<p>The risks these pose to respiratory health depend on the levels of exposure; “the dose makes the poison” is the central tenet of toxicology. In the case of damp houses, the dose is the concentration of airborne spores and fragments of moulds inhaled through personal exposure.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/8802/original/xgxr73kh-1332224560.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/8802/original/xgxr73kh-1332224560.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/8802/original/xgxr73kh-1332224560.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/8802/original/xgxr73kh-1332224560.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/8802/original/xgxr73kh-1332224560.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/8802/original/xgxr73kh-1332224560.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/8802/original/xgxr73kh-1332224560.jpg?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">
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<span class="caption">A home owner visiting her house for the first time over a month after Hurricane Katrina made landfall.</span>
<span class="attribution"><span class="source">EPA/DARREN HAUCK</span></span>
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</figure>
<p>According to the <a href="http://www.euro.who.int/__data/assets/pdf_file/0017/43325/E92645.pdf">World Health Organisation (WHO)</a>, there are currently no government or industry standards for acceptable levels of indoor airborne mould. This is because measuring exposure levels accurately is difficult; the threshold numbers that provoke asthma attacks are likely to vary with the moulds present; and the varying susceptibilities of exposed individuals. </p>
<p>Health risks for asthma depend on allergic sensitisation. When our team conducted a study of the environmental causes of asthma in 1996, we found 38% of our sample of allergic adults had a mould allergy. Most of these people were also sensitive to other allergens, predominantly house dust mite.</p>
<p>Multiple sensitisation makes the contribution of mould allergy to asthma severity difficult to assess. But our study suggested mould-allergic adults had twice the risk of asthma attacks and wheezing, and were also twice as likely to use asthma medication compared with adults with other allergies.</p>
<p>Clinical <a href="http://www.ncbi.nlm.nih.gov/pubmed/16507864">studies also suggest</a> that mould allergy is associated with more severe asthma, but more research in needed before we can be confident a causal relationship exists. </p>
<p>Even though the effects of moulds on health are not fully understood, the <a href="http://www.euro.who.int/__data/assets/pdf_file/0017/43325/E92645.pdf">WHO recommends</a> that dampness and mould-related problems be remediated because “they increase the risk of hazardous exposure to microbes and chemicals”. Remediation usually involves removal of mould-damaged building materials and furnishings, and the use of fungicides. </p>
<p>A <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD007897.pub2/abstract">2011 Cochrane Review</a> found that remediation marginally reduces asthma-related symptoms, respiratory infections and decreases the need for asthma medication. </p>
<p>Our <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1440-1843.2003.supp_1.x/pdf">2002 randomised controlled trial</a> (see page A33) of 13 mould-allergic adults showed that dehumidification and cleaning of bedroom surfaces with diluted bleach reduced airborne mould levels and was associated with a significant improvement in peak flow measurements. </p>
<p>Although there’s ongoing debate about whether the level of flooding we’ve recently experienced (and still are in some parts of the country) is due to global warming superimposed on natural Australian climate cycles, we are likely to see an increase in flooding and more exposure to moulds in the near future. </p>
<p>The <a href="http://climatecommission.gov.au/topics/the-critical-decade/">Climate Commission</a> believes rising ocean temperatures, changes in rainfall patterns, and extreme weather events will lead to increased relative humidity and more exposure to airborne allergens, such as pollens and moulds. And the <a href="http://www.csiro.au/Outcomes/Climate/Understanding/State-of-the-Climate-2012.aspx">climate paper</a> just released by <a href="http://www.csiro.au/">CSIRO</a> and the <a href="http://www.bom.gov.au/">Australian Bureau of Meteorology</a> provides further evidence of a continuing warming trend, which means the risk of mould-related respiratory problems will only increase in the future. </p>
<p>Further research may provide better solutions to the problem of mould-related allergies in the future. In the meantime, risks of respiratory problems can be mitigated by controlling relative humidity with improved insulation, heating and ventilation.</p><img src="https://counter.theconversation.com/content/5928/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Abramson receives funding from the NHMRC, the Victorian Health Promotion Foundation, Alfred Research Trusts and the University of Melbourne. The dehumidifiers for the trial were provided by Rollex. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article and has no relevant affiliations.</span></em></p><p class="fine-print"><em><span>Tom Jeavons 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 past five years have seen record rainfall and flooding in many towns and cities across eastern Australia. The floods themselves are dangerous, but so are the health hazards associated with the indoor…Tom Jeavons, Lecturer in Biomedical Sciences, Monash UniversityMichael Abramson, Professor of Clinical Epidemiology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.