7.3 Government and laws on the environment  (Page 3/7)

Clean air act

The Clean Air Act (CAA) of 1955 and subsequent amendments were established to improve the quality of the air resources in the United States. The CAA amendments of 1990 have provisions for maintenance of ambient air quality to promote and improve public health. Enforcement of regulations is carried out through the use of emission standards on stationary and mobile sources of air pollution that are directed at decreasing the production of air contaminants from various sources. A National Ambient Air Quality Standard (NAAQS) is the maximum permissible concentration of a contaminant in ambient air. Seven classes of air pollutants for which the NAAQS has been established are referred to as criteria pollutants: lead, nitrogen oxides, sulfur oxides, ozone, particulate matter smaller than 10 μm (PM ₁₀ ), hydrocarbons and carbon monoxide. Some pollutants have short-term and long-term standards designed to protect against acute and chronic health effects, respectively. In addition to criteria pollutants, Hazardous Air Pollutants (HAPs) are those pollutants that are known or suspect carcinogens, or may lead to other serious health effects over a longer period of exposure. The main sources of HAPs are industrial and automotive emissions. The CAA amendments of 1990 have provisions for the reduction in emission of HAPs that lead to lower concentrations of HAPs in ambient air.

The CAA amendments of 1990 established a permit program for larger sources of air emissions, where permits are issued by states or by the EPA. Information on the types of pollutants that are emitted, the emission levels, the monitoring of the emissions, and the plans to decrease the emissions is included in the permit. All applicable information on the emissions and legal responsibilities of the business are conveyed by the permit system. The 1990 CAA amendments provide several market-based approaches to businesses to reach their pollution cleanup thresholds such as pollution allowances that can be traded. In addition, economic incentives are provided to businesses to trade the extra credit for operations requiring less cleanup in exchange with the lesser credit given for operations requiring more cleanup.