Clean Air Act, United States

January 17, 2010, 3:38 pm
Source: Encyclopedia of Earth

Congress first enacted the Clean Air Act (CAA) in 1963 with the purpose of reducing air pollution from stationary sources such as power plants and steel mills. The CAA sets emission standards for stationary sources while promoting public health and welfare of the United States population. 95 million dollars over a three-year period financed state and local governments and air pollution control agencies, enabling them to conduct research and create control programs. Within the CAA, Congress also recognized the hazards of motor vehicle exhaust and mandated research, investigations, surveys, and experiments on interstate pollution from the use of high sulfur coal and oil. In 1965, the Motor Vehicle Air Pollution Control Act amended the 1963 Clean Air Act.

The next major revision of The Clean Air Act occurred in 1970. The CAA of 1970 encompasses multiple levels of research funding and detailed control requirements that the federal government prescribes as regulation, and state governments apply and administer. The centerpiece of the Clean Air Act is the National Ambient Air Quality Standard (NAAQA) program. The NAAQS sets standards for six pollutants: sulfur dioxide; nitrogen dioxide; particulate matter; carbon monoxide, ozone; and lead. These substances are regulated under the CAA because they have been identified as dangers to public health and welfare.

The Clean Air Act of 1970 also created new source emission regulation standards set by the New Source Performance Standards (NSPS). All new plants, or major additions to existing plants, need to abide by the NSPS. The Environmental Protection Agency (EPA) determines standards for each new source by evaluating cost, environmental effects, and technology availability. New sources are subject to stricter emissions control technology and permitting specification. However, existing plants are exempt from this requirement for various reasons.

Each state is given primary responsibility for assuring that emissions sources from within their borders are consistent with the levels designated by the NAAQS. In order to achieve these goals, each state is required to submit a State Implementation Plan (SIP) to the EPA to ensure the implementation of primary and secondary air quality standards. The CAA of 1970 contains substantive procedural requirements governing the development and approval of each SIP.

Since many states failed to meet mandated air quality standards first set by the Clean Air Act, Congress created the 1977 amendments to aid states in achieving their original goals. One major revision tightens pollution control for newly built sources and brings older plants under the Clean Air Act’s regulations. It instituted the New Source Review (NSR), which requires companies to obtain permits before modifying equipment.

Congress enacted another major modification in 1990; the Clean Air Act of 1990 introduces a permit program for large sources that release pollutants into the air. The permit includes information on which pollutants are being released, how much may be released, and steps the source’s owner or operator are taking to reduce the pollution. This permit system simplifies and clarifies business’ obligations for reducing air pollution. The 1990 Clean Air Act includes other provisions to reduce interstate air pollution, and covers pollution that originates in Mexico and Canada that is transported into the United States as well as pollution that originates in the United States and affects Canada and Mexico. The EPA's enforcement powers broadened with the new amendment; the EPA is now authorized to fine violators and increase penalties for violations of the Act.

The 1990 amendment also addresses acid rain pollution by creating a market-based system as a means to reduce sulfur dioxide emissions from power plants. There are two phases; Phase I targets the highest emission producing plants, which were expected to achieve reductions by 1995, and Phase II, which began in 2000, affects smaller plants and calls for stricter reductions from Phase I sources. Companies are allowed to either bank their allowances or trade them with other companies.

On December 31, 2003, amendment votes on the 2003 budget bill changed New Source Review pollution control provisions. These amendments give companies the option to not update emission controls if their plant’s equipment has been reviewed in the last decade. Additionally, communities are no longer able to publicly comment when power plants expand production and increase emissions.

Further Reading
Information on New Source Review (U.S. Environmental Protection Agency)
Features of the 1990 Clean Air Act (U.S. Environmental Protection Agency)
Highlights of the 1990 Clean Air Act Amendments (U.S. Environmental Protection Agency)

Kenney, Robyn (Lead Author); Richard Rich (Topic Editor). 2006. "Clean Air Act, United States." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [Published in the Encyclopedia of Earth October 4, 2006; Retrieved September 17, 2008]. <,_United_States>


(2010). Clean Air Act, United States. Retrieved from

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