Criteria Air Pollutants
The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS)National Ambient Air Quality StandardsStandards established by EPA for maximum allowable concentrations of six "criteria" pollutants in outdoor air. The six pollutants are carbon monoxide, lead, ground-level ozone, nitrogen dioxide, particulate matter, and sulfur dioxide. The standards are set at a level that protects public health with an adequate margin of safety. for six common air pollutants (also known as "criteria air pollutants"). These pollutants are found all over the U.S. They can harm your health and the environment, and cause property damage.
Learn how EPA sets, reviews and revises standards and (primary standards
primary standardsNational ambient air quality standards designed to protect human health with an adequate margin for safety. and secondary standards
secondary standardsNational ambient air quality standards designed to protect welfare, including effects on soils, water, crops, vegetation, man-made (anthropogenic) materials, animals, wildlife, weather, visibility, and climate; damage to property; transportation hazards; economic values, and personal comfort and well-being.), standardsNational ambient air quality standards designed to protect welfare, including effects on soils, water, crops, vegetation, man-made (anthropogenic) materials, animals, wildlife, weather, visibility, and climate; damage to property; transportation hazards; economic values, and personal comfort and well-being.determines whether areas meet the standards, and works with areas to attain and maintain the standards.

