Toxic Air Pollutants

What Are Toxic Air Pollutants?

Toxic, or hazardous, air pollutants cause or are suspected of causing cancer, birth defects, or other serious harms.  They can be gases, like hydrogen chloride, benzene or toluene, dioxin, or compounds like asbestos, or elements such as cadmium, mercury, and chromium. The U.S. Environmental Protection Agency has classified 187 pollutants as hazardous.

Just because a pollutant is not listed on the list as "hazardous" does not mean that it does not cause cancer or is safe to breathe, however. Other air pollutants like particle pollution can also cause cancer or other serious hazards.

What Are the Health Effects from Toxic Air Pollutants?

Toxic air pollutants pose different risks to health depending on the specific pollutant, including:

• Cancer, including lung, kidney, bone, stomach
• Harm to the nervous system and brain
• Birth defects
• Irritation to the eyes, nose and throat
• Coughing and wheezing
• Impaired lung function
• Harm to the cardiovascular system
• Reduced fertility

How Are People Exposed to These Pollutants?

People inhale many of these pollutants in the air where they live. But, because these pollutants also settle into waterways, streams, rivers and lakes, people can drink them in the water or eat them in the fish from these waters. Some hazardous pollutants settle into the dirt that children play in and may put in their mouths.

One of the common chemicals used in riot control agents, or "tear gas," is a toxic air pollutant. Learn more about the health effects of tear gas.

Where Do Toxic Air Pollutants Come From?

Major sources of toxic air pollutants outdoors include emissions from coal-fired power plants, industries, and refineries, as well as from cars, trucks and buses.

Indoor air also can contain hazardous air pollutants from sources that include tobacco smoke, building materials like asbestos, and chemicals like solvents.

Fortunately, thanks to the Clean Air Act, many of these sources are being cleaned up, though more remains to be done.  This report, Toxic Air: The Case for Cleaning Up Coal-fired Power. describes the hazardous air pollutants from coal-fired power plants. More details are in a longer report, Emissions of Hazardous Air Pollutants from Coal-fired Power Plants.

Find information about air toxics in your community

EPA has two nationwide databases that provide information on emissions near you.

• National Air Toxics Assessment – This site reports on 33 air toxics that EPA rates as the greatest threat to public health in the largest number of urban areas. Available information includes maps and lists by state or county level.
• Toxics Release Inventory – Type in your zip code and learn about releases of toxic chemicals into the environment through the air, water, and land from manufacturing facilities.

For more information:

• U.S. EPA. Hazardous Air Pollutants
• Agency for Toxic Substances and Disease Registry. Toxic Substances Portal