In Paris’s André-Citroën Park, a balloon is used to measure air pollution.
The number of substances emitted into the atmosphere is immense and growing, but some are particularly harmful to health and are subject to increased monitoring.
Industrial facilities like this oil refinery in Anacortes, Washington are significant air pollution sources.
An air pollution expert with years of experience advising federal regulators describes how the Trump administration is speeding up reviews and reducing scientific input.
The Big Brown coal plant in Fairfield is among the Texas power stations that have been shut down.
AP Photo/David J. Phillip
A study of the social cost of carbon emitted by the shrinking fleet of Texan coal plants suggests that closing more of them down would be good for the climate and public health.
A study finds that higher ozone levels correlate with slower performance times for college endurance athletes.
US ozone pollution has fallen in recent decades, but exposure to low levels of ozone still has serious effects on human health and well-being.
Researchers release a balloon carrying instruments to measure ozone levels above Antarctica.
Almost 30 years ago the world responded to the realisation that our ozone layer was in trouble. The resulting Montreal Protocol was a rare example of global cooperation, but there's no room for complacency.
A clear day at Acadia National Park in Maine.
US national parks protect some of America's most spectacular outdoor settings. But new research shows that ozone pollution levels in the parks are roughly as bad as in major cities.
Smog alert in Cleveland, Ohio, July 20, 1973.
EPA Administrator Scott Pruitt wants to change the grounds for setting US air pollution targets. An environmental lawyer explains why Pruitt's approach misreads the law and could roll back decades of gains.
Good for you, bad for the air?
New research is spotlighting personal care products, such as shampoos and skin lotions, as a significant source of chemicals that contribute to urban air pollution.
False-color image of ozone concentrations above Antarctica on Oct. 2, 2015.
NASA/Goddard Space Flight Center
Earth's ozone layer shields us from harmful ultraviolet radiation. Nations have been working to reduce ozone-depleting chemicals since the 1980s, but recent studies show that there is still work to do.
When present in the lowest atmospheric layer – the troposphere, 8-14 kilometers above earth – ozone becomes a concern for human and plant health.
When present in the lowest atmospheric layer, ozone becomes a concern for human and plant health.
Beijing residents with a variety of approaches to urban air pollution.
In recent years the number of motor vehicles – and the pollution they generate – has grown astronomically, leading some citydwellers to wear facemasks in the hopes of protecting themselves. So do they work?
The Montreal Protocol is finally closing the hole in the ozone layer.
A boy plays cricket among smoke in Karachi. Deaths from air pollution across the globe will increase as climate change accelerates.
A new study suggests climate change will cause changes to patterns of ground-level ozone and smog – two deadly pollutants set to increase deaths by about 260,000 worldwide by the end of the century.
You can only truly understand the weather by flying above the clouds.
Far from being "politicised science", as a Trump advisor has claimed, NASA's satellite monitoring has been a crucial help in understanding the planet we live on.
The Montreal Protocol has successfully reduced the use of chemicals that destroy the Earth’s ozone layer.
Atmosphere image from www.shutterstock.com
Hydrofluorocarbons were created to replace ozone-damaging chemicals – but they turned out to be major contributors to climate change.
Houston in 2002.
U.S. states need to put in place new ozone air quality standards, but how they are measured – based on peak ozone – doesn't always best reflect a city's overall air quality.
Smog over Mexico City: bad air quality has led to limits on when people can drive their cars in the city.
Mexico City is suffering through an air quality crisis this spring, but institutional corruption is making the proposed solution – restricting car usage – ineffective.
Aided by expanded farming in Asia, there’s been a global increase in greenhouse gases from farming.
The Paris climate summit yielded a pact to reduce air pollutants that contribute to global warming but missed a chance to address the interlinked effects of agriculture and climate.
A worker at a coal power plant in China.
The greenhouse gases that cause climate change will take centre stage at the upcoming Paris climate talks. What are they and what are their effects?
Conflicting evidence means it's tough to tell whether trees helping to clear the air, or if green is not as good as we thought.