Air pollution rules and standards
Special rules are needed to implement various goals related to air pollution. It is usually desirable to write laws in general and allow government legislatures to add more detail to their studies. The EPA and the Senate use this approach.
Two types of standards include ambient air quality standards (AAQS), which are related to the concentration of pollutants in the external environment, and resource performance standards (SPS), which are related to the emission of pollutants from a specific source.
AAQS are always expressed in terms of microgram concentration per cubic meter or ppm, while SPSs are always expressed in terms of mass emitted per unit time or product unit.
Under current law, ambient air quality standards are issued for six pollutants: particulate matter (10-PM), sulfur dioxide, nitrogen dioxide, carbon monoxide, ozone, and lead.
National standards for pollutants are set by the Environmental Protection Agency based on two criteria: primary standards for public health and secondary standards for public welfare.
The two are different in that public welfare can have effects other than health.