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Air pollution initially was recognized more as a nuisance than as a threat to human health. In the early 1300's, Edward I of England ordered that the burning of sea coal in craftsman's furnaces be prohibited because of the foul-smelling fumes produced. Centuries later, Elizabeth I banned, for similar reasons, the burning of coal in London while Parliament was in session.
Some of the first regulations enacted for the control of air pollution happened in the late 1800s and early 1900s in England and the United States. Our modern air pollution control program can be said to have evolved from these early ordinances.
The federal government of the United States began efforts to control air pollution in the 1950s with the passage of the Air Pollution Control Act of 1955. This was the first federal air pollution law, and it mandated federal research programs to investigate the health and welfare effects of air pollution. It also authorized the federal government to provide technical assistance to state governments. Additional legislation was passed in 1963 and 1965.
II. The Clean Air Act of 1970
In 1970, the Environmental Protection Agency (EPA) was formed along with the Clean Air Act of 1970. The formation of EPA marked a dramatic change in national policy regarding the control of air pollution. Whereas previous federal involvement had been mostly in an advisory and educational role, the new EPA emphasized stringent enforcement of air pollution laws. The passage of the Clean Air Act of 1970 marked the beginning of modern efforts to control air pollution.
The highlight of the 1970 amendments was the establishment of an air quality management approach based on the adoption on National Ambient Air Quality Standards (NAAQS). These standards limit the concentrations of pollutants that "endanger the public health or welfare."
Initially, NAAQS were established for six pollutants:
and non-methane hydrocarbons
For stationary sources, the act required EPA to establish New Source Performance Standards (NSPS) for all major categories of polluting facilities. These standards still apply today, and are based on the best demonstrated technology (BDT).
The 1970 Clean Air Act established goals for both mobile and stationary sources of air pollution that forced the automotive industry to develop new technologies for emissions control. The new law required automobile manufacturers to reduce pollutant emissions by 90% from new vehicles by 1975. Specific limits were set for emissions of carbon monoxide, hydrocarbons, and nitrogen oxides from automobiles.
Another major requirement of the 1970 act was that each state submit a State Implementation Plan (SIP) to the EPA. These plans, which are still in effect, outline detailed steps to be taken to meet ambient air quality standards. Each state was required to establish Air Quality Control Regions (AQCRs), and using them to devise requirements for controlling air pollution related to specific local needs.
The Clean Air Act of 1970 legislated regulations called National Emissions Standards for Hazardous Air Pollutants (NESHAPs). This legislation required EPA to regulate toxic or hazardous air pollutants based on health risk standards levels that would provide an ample margin of safety to protect the public health. To date, NESHAPs have been established for eight toxic air pollutants:
III. The Clean Air Amendment of 1977
The Clean Air Act of 1970 was amended in 1977. The Act now focused on the concept of prevention of significant deterioration (PSD). EPA was required to issue regulations to prevent degrading the air in areas where the air is already cleaner than required by the national ambient air quality standards.
The cornerstone of the PSD program is a process known as New Source Review (NSR). All major new or modified stationary sources of air pollution are required to obtain a New Source Review permit before beginning construction.
IV. The Clean Air Act Amendments of 1990
The Clean Air Act was amended again in November of 1990. The new legislation placed renewed emphasis on controlling emissions of hazardous air pollutants and introduced efforts aimed at controlling acid rain and ozone depletion in the atmosphere.
Regulatory programs designed to control hazardous air pollutants (HAPs) were first initiated by the states. The basis for regulating a toxic air pollutant was usually the list of threshold limit values (TLVs) published by the American Conference of Governmental Industrial Hygienists (ACGIH).
Man-made pollution is one of the primary causes of acid rain. Sulfur oxides and nitrogen oxides produced by the burning of fossil fuels combine with water in the atmosphere to produce acid rain. The CAAA of 1990 require sulfur oxide and nitrogen oxide emissions to be reduced from major sources of these pollutants. The amendments also call for continued research into the effects of acid rain deposition and transport.
An innovative approach to acid rain control promoted by the 1990 amendments is the use of market-based incentives. The amendments encourage this approach as a way to reduce the costs of compliance with air pollution standards.
Researchers have discovered that synthetic compounds, such as chlorofluorocarbons (CFCs) and halons are breaking down the protective ozone layer in the stratosphere. These compounds are used in many common products, such as refridgerants, aerosol sprays, and fire extinguishers. EPA recognized this threat and initially began to conduct further research on ozone depletion as a result of congressional directive in the Clean Air Act of 1977. The United States also participated in the Montreal Protocol, which established an international effort to phase out ozone-depleting substances. The 1990 amendments require the complete phaseout of CFCs and other ozone-depleting compounds by the year 2000.