Air Quality

Air quality is essential for protecting public health and the environment across the United States. The Clean Air Act gives the Environmental Protection Agency (EPA) authority to set National Ambient Air Quality Standards (NAAQS) that limit pollutants in outdoor air. These standards help reduce harmful emissions from sources such as factories, power plants, and vehicles, ensuring cleaner air for communities nationwide.

National Standards and State Implementation

The EPA identifies six common air pollutants—carbon monoxide, ground-level ozone, lead, nitrogen oxides, particulate matter, and sulfur dioxide—and sets limits for each. Areas meeting these limits are called “attainment areas,” while those exceeding them are “nonattainment areas.” States develop State Implementation Plans (SIPs) outlining how they will meet and maintain these standards. This federal-state partnership balances national goals with regional strategies to improve air quality.

Regulation and Compliance

EPA enforces emissions controls on both stationary sources, like industrial facilities, and mobile sources, such as vehicles. Facilities must comply with emission limits and obtain permits, often using the best available pollution control technologies. For hazardous air pollutants, the agency requires the maximum achievable control technology (MACT) standards to minimize emissions. States monitor air quality and enforce regulations to protect their communities effectively.

Air Quality and Health

Clean air is vital for health, as poor air quality can lead to respiratory and cardiovascular diseases among other health issues. To understand how air quality impacts your health and what actions you can take, see the detailed information in the category article Air Quality and Your Health.