Although environmental laws had been enacted prior to the Clean Air Act (CAA) of 1970, none were as comprehensive in the regulation of air pollution from stationary (industrial) and mobile sources (cars, trucks, and planes). Congress simultaneously enacted the National Environmental Policy Act, which created the U.S. Environmental Protection Agency and authorized it to implement the many requirements included in the Clean Air Act of 1970. Major amendments to the CAA were passed in 1977 and 1990.
Of particular importance to the work of NELC, the Clean Air Act authorizes the public to bring citizen suits against companies that violate the law if state and federal agencies fail to act.
The current CAA includes four basic programs:
The current CAA contains a variety of programs to address air pollution, including tailpipe emission standards for mobile sources and emissions-trading programs for pollutants associated with acid rain, but NELC’s work tends to focus on five major CAA programs:
National Ambient Air Quality Standards (NAAQS)
EPA regulates six of the most common (“criteria”) air pollutants – carbon monoxide, lead, nitrogen oxides, ozone, particulate matter and sulfur oxides – by specifying the allowable concentrations of each pollutant in the ambient air. These national, uniform standards are set at a level intended to protect public health. EPA is required to periodically review scientific literature and ensure that the NAAQS protect at-risk populations, including children.
State Implementation Plans (SIPs)
Ensure states achieve compliance with the federally established NAAQS. States submit detailed plans for the implementation, maintenance and enforcement of national ambient air quality standards. SIP proposals may include various methods for achieving compliance, including restricting emissions from certain sources and imposing new technological controls. Once a SIP is adopted by the EPA, however, its provisions must be followed by the state.
New Source Performance Standards (NSPS)
Complement efforts to achieve compliance with NAAQS standards by regulating individual sources of air pollution. These “technology forcing” standards require new sources of pollution to install the “best system of emission reduction” available to a designated industry. EPA determines the “best system of emission reduction” by reviewing current technologies. It maintains a list of NSPS technologies for criteria pollutants in all major polluting industries.
National Emission Standards for Hazardous Air Pollutants (NESHAPS)
Regulate the emission of 189 air toxics from individual, stationary sources. Hazardous air pollutants are less pervasive than criteria pollutants, but are extremely harmful to human health and air quality. The EPA sets “technology-based” limits for each pollutant, requiring “the maximum degree of reductions in emissions that is deemed achievable” within a specific industry.