Clean Air Act Enforcement
The Clean Air Act (CAA), passed in 1970, created a national program to control the damaging effects of air pollution. The Clean Air Act Amendments of 1990 went further to ensure that the air Americans breathe is safe. The CAA protects and enhances the quality of the nation's air by regulating stationary and mobile sources of air emissions.
The CAA requires major stationary sources to install pollution control equipment and to meet specific emissions limitations. In addition, for the first time under the 1990 CAA amendments, major stationary sources must obtain operating permits. Examples of stationary sources include manufacturers, processors, refiners, and utilities.
The CAA mandates controls on air pollution from mobile sources by regulating both the composition of fuels and emission-control components on motor vehicles and nonroad engines. Vehicle fuel standards for gasoline and diesel are met by refiners/ importers, and by other parties in the fuel distribution system.
Regulation of vehicles includes vehicle emission limits for Hydrocarbons (HC), Carbon Monoxide (CO), and Nitrogen Oxides (NOx), and particulates in the case of diesel vehicles. These limits, which must be met by the vehicle manufacturers, apply to on-road vehicles, off-road vehicles, and non-road sources (e.g., marine engines, locomotives, and lawn & garden equipment). Under the 1990 CAA amendments, vehicle standards are being made more stringent, in stages, through 2005 or later.