Air Pollution: Federal Law And Regulation

The Clean Air Act (CAA) is the primary federal law that regulates air pollutants in the United States. The Act was first enacted in 1963 and has since been amended several times, most notably in 1970, 1977, and 1990. The Clean Air Act gives the Environmental Protection Agency (EPA) the authority to regulate air emissions from stationary and mobile sources, such as chemical plants, utilities, and steel mills. The EPA sets National Ambient Air Quality Standards (NAAQS) for common air pollutants and requires major stationary sources to install pollution control equipment and meet specific emissions limitations. The Clean Air Act has been instrumental in reducing air pollution in the United States and continues to protect public health.

The Clean Air Act (CAA)

The Clean Air Act was initially enacted in 1963 and has been amended several times since, making it one of the country's first and most influential modern environmental laws. The 1963 act was built on the Air Pollution Control Act of 1955, which first allocated federal funding for research. The Clean Air Act of 1970, born out of the deadly Donora smog incident of 1948, is considered a significant amendment to earlier laws. Further amendments in 1977 and 1990 set new goals and dates for achieving National Ambient Air Quality Standards (NAAQS).

The Clean Air Act recognises the right to healthy air quality for all Americans, regardless of their state of residence. It addresses emissions from stationary and mobile sources, aiming to achieve NAAQS in every state. The EPA establishes NAAQS to protect public health and welfare and regulate hazardous air pollutants. State Implementation Plans (SIPs) are developed by states to meet these standards, and the EPA steps in if state plans fall short.

Section 112 of the Clean Air Act specifically targets emissions of hazardous air pollutants. The 1990 amendments to this section introduced technology-based standards, requiring major sources to adopt Maximum Achievable Control Technology (MACT) standards to reduce emissions. The EPA is responsible for reviewing and revising these standards to address any residual risks.

The Clean Air Act has been instrumental in reducing air pollution in the United States, improving air quality, and protecting public health. It has curbed major environmental and health threats, including acid rain, urban air pollution, toxic air emissions, and stratospheric ozone depletion. The Act also includes programs that address vehicle fuels, industrial facilities, and other activities impacting air quality. The CAA has faced legal challenges from both environmental groups seeking stricter enforcement and states desiring greater flexibility in regulation.

National Ambient Air Quality Standards (NAAQS)

The Clean Air Act, a comprehensive federal law, regulates air emissions from stationary and mobile sources. It requires the Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQS) for six principal pollutants or "criteria pollutants" that are common in outdoor air, harmful to public health and the environment, and that come from numerous and diverse sources. These pollutants include particulate matter, ozone, nitrogen oxides, sulfur oxides, carbon monoxide, and lead.

The NAAQS are selected by the EPA Administrator at the conclusion of a public process that takes about five years. The process starts with a comprehensive review of the relevant scientific literature, which is summarized in a document called the Integrated Science Assessment (ISA). Based on the ISA, EPA staff perform a risk and exposure assessment, which is summarized in the Risk and Exposure Assessment (REA) document. The third document, the Policy Assessment (PA), integrates the findings and conclusions of the ISA and REA into a policy context and provides lines of reasoning for retaining or revising the existing NAAQS, as well as suggesting alternative standards. Each of these three documents is released for public comment and peer review by the Clean Air Scientific Advisory Committee (CASAC), a subcommittee of the EPA's Science Advisory Board.

Once all three documents are finalized, they are given to the EPA Administrator to use in selecting a proposed NAAQS, which is released through the Federal Register for public comment. Following the close of the comment period, the Administrator considers the comments received, makes changes to the proposed NAAQS if necessary, and publishes the final NAAQS in the Federal Register. The Clean Air Act requires the EPA to review and, if necessary, revise each of the NAAQS at five-year intervals to ensure that they are based on the most recent scientific findings.

The statute establishes two types of NAAQS: primary standards, which are designed to protect public health with an adequate margin for safety, and secondary standards, which are designed to protect the public welfare from adverse effects, including those related to soils, water, crops, vegetation, man-made materials, animals, wildlife, weather, visibility, and climate; damage to property; transportation hazards; economic values; and personal comfort and well-being. The Clean Air Act Amendments of 1970 instruct the EPA to set primary NAAQS to protect public health and secondary NAAQS to protect plants, forests, crops, and materials from damage due to exposure to the six air pollutants. Federal law requires that all states attain the NAAQS. Nonattainment areas must develop plans to attain the NAAQS, and attainment areas must develop plans to maintain attainment.

State Implementation Plans (SIPs)

The Clean Air Act, a comprehensive federal law, empowers the US Environmental Protection Agency (EPA) to regulate air pollutants and polluting industries. The Clean Air Act of 1970 was built on precursors such as the Air Pollution Control Act of 1955, which provided funding for research, and the Clean Air Act of 1963, which focused on research expansion and a new public health program. The Air Quality Act of 1967 recognised that states and local governments should address their pollution problems, but the federal government could intervene if states failed to act.

The Lowest Achievable Emissions Rate (LAER) is employed by the EPA to assess whether emissions from new or modified major stationary sources are acceptable under SIP guidelines. LAER standards are mandated when a new stationary source is located in an area that does not meet air quality standards. This standard is more stringent than the best available control technology and reasonably available control technology standards.

An example of a successful SIP is the one implemented in Ohio between 1970 and 1977. During this period, a Clean Air Act rule required a reduction in sulfur dioxide (SO2) emissions from coal-fired power plants. The SIP to address this issue involved increasing the height of smokestacks, which resulted in SO2 being carried by wind out of the state, leading to a significant reduction in measured SO2 levels near the source.

SIPs are essential for ensuring that states comply with the Clean Air Act and work towards improving air quality. They provide a framework for states to develop strategies that address specific air pollution challenges within their respective regions.

New Source Performance Standards (NSPS)

The Clean Air Act (CAA) is the comprehensive federal law that regulates air emissions from stationary and mobile sources. The law gives the US Environmental Protection Agency (EPA) the authority to regulate air pollutants and polluting industries. The Clean Air Act of 1970 was built on important precursors, including the Air Pollution Control Act of 1955, which was the first piece of legislation regarding air pollution.

NSPS have been established for a variety of individual industrial or source categories. For each type of facility, the type of pollutant control technology must be identified. This involves studying all available information about the plants and their technologies to establish an allowed concentration of the criteria pollutants, which is the upper limit of what can be emitted. Under the Clean Water Act, NSPS set the level of allowable wastewater discharges from new industrial facilities.

In developing NSPS, the Clean Water Act (CWA) requires the EPA to determine the "best available demonstrated control technology" (BADCT) for the particular industrial category. BADCT may be more stringent than the best available technology economically achievable standard used for existing dischargers. This consideration may include setting a "zero discharge of pollutants standard" if practicable.

NSPS sources that meet the Clean Air Act definition of "major source" generally receive a full compliance evaluation by the state at least once every two years. EPA measures NSPS compliance by requiring affected facilities to conduct initial performance tests, followed by continuous monitoring of operating parameters and/or direct monitoring of regulated emissions.

National Emissions Standards for Hazardous Air Pollutants (NESHAPs)

The Clean Air Act is the comprehensive federal law that regulates air emissions from stationary and mobile sources in the United States. The law gives the Environmental Protection Agency (EPA) the authority to regulate air pollutants and polluting industries. The EPA develops national enforcement initiatives that focus on significant environmental risks and noncompliance patterns.

NESHAP sources that meet the Clean Air Act definition of "major source" are generally subject to a full compliance evaluation by the state or regional office at least once every two years. The EPA may require sources to install and operate continuous emission monitors to demonstrate compliance.

Under Section 112 of the Clean Air Act, the EPA must establish emission standards that require the maximum degree of reduction in emissions of hazardous air pollutants. These standards are commonly referred to as "maximum achievable control technology" or "MACT" standards. Eight years after the MACT standards are issued for a source category, the EPA reviews and revises them if necessary to address any residual risk.

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