Clean Air Act

History of Air Pollution

Air pollution has been a concern in large cities for many years. As early as 900 B.C.E., air pollution was noted in Babylon in an asphalt mine as a “strange [Page 124]smell in the air.” Air polluted with dark smoke, fog, stench, and soot was described as unbearable in Rome, Egypt, and, later, in England over the following centuries. Various rules and regulations were imposed to control air pollution. For example, in the beginning of the 14th century, the king of England banned the use of sea coal to reduce smoke in London.

The Industrial Revolution in the 18th century caused fast population growth and economic development in the Western world. A high level of coal combustion during this period led to the rise of pollutants in the air, which became hazardous to human health, especially in large cities. Chicago and Cincinnati were the first U.S. cities to attempt to reduce air pollution by means of legislation in 1881. Over the next half-century, other cities introduced their own regulations to control smoke emission.

Finally, because of public outcry and the continuous deterioration of living conditions in cities, the federal government decided to intervene and introduced the Air Pollution Control Act of 1955 under President Dwight D. Eisenhower. This act provided federal funding for the scientific research of air pollution. The Clean Air Act of 1963 was the first federal legislation to control air pollution. In 1967, the Air Quality Act was expanded to monitor and control interstate transport of air pollution. The Clean Air Act continued to be revised and amended, resulting in major amendments in 1970, 1977, and 1990.

Joint Effort

The CAA is the result of a continuous and joint venture in managing air quality, involving many parties in the United States. Three executive agencies—the Environmental Protection Agency (EPA), the Council on Environment Quality (CEQ), and the Office of Management and Budget (OMB)—worked on the legislation with other federal, state, and local government agencies, such as Congress, state governors, county officials, mayors, city council members, state legislators, state and local air agencies, the courts, and other federal agencies. Major industry and trade organizations, small businesses, farms, scientists, engineers, academia, research organizations, the Clean Air Scientific Advisory Committee (CASAC), environmental and public health groups, and the people of the United States contributed to the legislation and implementation of CAA and its amendments.

Standards

In a major amendment in 1990, the EPA established the goals for National Ambient Air Quality Standards (NAAQS). The acceptable limits of the six principal pollutants (carbon monoxide, lead, nitrogen oxides, sulfer dioxide, particulate matter, and ozone), measured in parts per million (ppm) or by volume, (mg/m3) of air, for primary and secondary standards are defined by the CAA. The Primary standards, are set to limit air pollutants to protect public health, including “sensitive” populations, such as asthmatics, children, and the elderly.

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