Clean air

Clean air

The world's transportation fleet—passenger cars and light trucks, heavy trucks and buses, motorcycles and scooters and three-wheelers, farm tractors and construction equipment, ships and planes—is a massive source of outdoor air pollution, especially in urban areas. The effects of long-term exposure to fine particulates, nitrogen oxides, hydrocarbons, carbon monoxide, air toxics and other pollutants contained in vehicle exhaust include lung cancer, heart disease, stroke, asthma, stunted lung growth in children, and other harmful outcomes. And in some cases, as with the black carbon that is a component of particulate emissions, these pollutants also contribute to short-term climate warming.

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About the program

The world's transportation fleet—passenger cars and light trucks, heavy trucks and buses, motorcycles and scooters and three-wheelers, farm tractors and construction equipment, ships and planes—is a massive source of outdoor air pollution, especially in urban areas. The effects of long-term exposure to fine particulates, nitrogen oxides, hydrocarbons, carbon monoxide, air toxics and other pollutants contained in vehicle exhaust include lung cancer, heart disease, stroke, asthma, stunted lung growth in children, and other harmful outcomes. And in some cases, as with the black carbon that is a component of particulate emissions, these pollutants also contribute to short-term climate warming.

The Clean Air Program advises governments and civil society organizations on strategies to address the public health and near-term climate impacts of outdoor air pollution from motorized transportation. We develop technical underpinnings for the design and implementation of emission control policies to mitigate those impacts at the international, national, and city scales. These policies can include national vehicle emission standards, fuel-quality standards to limit the sulfur content of diesel and petrol, compliance and enforcement programs to ensure that standards are met in practice, vehicle scrappage and retrofit programs, and other actions like establishment of low-emission zones. And we undertake monitoring and assessment of real-world emissions, air quality, and public health impacts to evaluate progress and guide actions where they are needed most.

State of global air quality: Regional insights from Brazil, China, India, and Mexico

The state of global air quality: Regional insights from Brazil, China, India, and Mexico.

Recent publications

Financing the transition to soot-free urban bus fleets in 20 megacities

Addresses the opportunities for facilitating, and the barriers to financing, the transition to soot-free urban bus fleets in 20 megacities.

2017.10.11 | Report
Low-carbon technology pathways for soot-free urban bus fleets in 20 megacities

Evaluates well-to-wheel greenhouse gas emissions from soot-free urban transit bus types in 20 megacities.

2017.08.31 | Working paper
Impacts and mitigation of excess diesel NOx emissions in 11 major vehicle markets

Diesel vehicles in major markets produce over 50% more NOx than official certification limits indicate. Study links these excess NOx emissions to ~38,000 premature deaths worldwide in 2015—mostly in the EU, China, and India. 

2017.05.15 | Report
See all publications

Staff blog

Glider industry petition in support of glider trucks debunks itself

The summary of a "study" that the glider industry used to support its claim that EPA was wrong about how dirty gliders are is fingernails-on-a-chalkboard aggravating.

Staff