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.
President George H.W. Bush (right) fishing on the Kennebunk River in Maine, Aug. 27, 1990.
AP Photo/Doug Mills
George H.W. Bush, who pledged to be 'the environmental president,' took a market-based approach to pollution control that helped clear the air. Now some experts think it could work on climate change.
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.
An image from the International Space Station captures plumes of smoke from California wildfires on August 4, 2018.
Haze from Northern California wildfires has drifted as far east as Philadelphia. Wildfire smoke contains many potentially toxic substances, so anyone exposed to it should take basic precautions.
A Kosovo policeman directs cars in Pristina after the government banned traffic in response to extremely high fine particle pollution levels, Jan. 31, 2018.
AP Photo/Visar Kryeziu
The head of the World Health Organization calls air pollution 'the new tobacco' because it causes millions of preventable deaths yearly. Fine particle pollution is especially deadly.
John Williams RUS/Shutterstock.
London's low emission zone has started to reduce air pollution – but not enough to protect children's lungs.
VW was hit with more than $15 billion in penalties in the United States.
How could a company like Volkswagen knowingly violate US air-pollution standards despite the senseless risks to which it was exposing its reputation? The case method can provide an answer.
Kittipong33 / shutterstock
These substances can generate air pollution particles.
As traffic slows down, research is gathering momentum.
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.
The US government is set to make it easier for oil and gas firms to leak methane into the atmosphere.
Can Walmart go green while maintaining its commitment to low prices?
AP Photo/Tom Uhlman
Two business professors spent five years studying Walmart's ambition project to bring sustainability to its millions of budget-conscious customers – a plan that began with the birth of a granddaughter.
Taj Mahal is one of the most beautiful buildings in the world, but over the last four centuries it has aged and darkened from pollution.
Rob from Harwick, Stockton-on-Tees, where life expectancy is low, spoke to BBC Panorama about health inequalities.
In a developed country like the UK, why can life expectancy within just a few miles differ by as much as 18 years?
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.
Fire burns the hillsides along Highway 129 near Lake Berryessa in Yolo County, California, on July 3, 2018.
(Randall Benton/The Sacramento Bee via AP)
And wildfires rage along the West Coast of North America, parents should know the impact on their children's health, and how to protect them.
Afternoon traffic into Nairobi’s CBD.
Research shows that cities benefit from car-free days in many ways.
Daily routine affects how much polluted air we breathe.
A large dust storm, or haboob, sweeps across downtown Phoenix on July 21, 2012.
AP Photo/Ross D. Franklin, File
New research projects that climate change could greatly increase airborne dust levels in the southwestern US, causing higher hospital admissions and premature deaths from heart and lung ailments.
Two air pollution experts analyse the government's plan.