National Ambient Air Quality Standards (NAAQS)

To control ambient air quality, the Clean Air Act, which was last amended in 1990, requires the Environmental Protection Agency (EPA) to set NAAQS for pollutants that are considered to be harmful to public health and the environment. The Clean Air Act established two types of standards for ambient air quality. Primary standards concern the minimum level of air quality necessary to keep people from becoming ill and are aimed at protecting public health. These primary standards are intended to provide an adequate margin of safety for the public, which has been defined to include a representative sample of so-called sensitive populations such as the elderly, children, and asthmatics. The secondary standards are aimed at the promotion of public welfare and the prevention of damage ...