Reviewing National Ambient Air Quality Standards (NAAQS): Scientific and Technical Information
The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for pollutants that are common in outdoor air, considered harmful to public health and the environment, and that come from numerous and diverse sources.
The statute established two types of national air quality standards: primary standardsprimary standardsNational ambient air quality standards designed to protect human health with an adequate margin for safety. and secondary standardssecondary 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.. This website provides scientific and technical information about the current or prior review of the NAAQS.