Legislating For Cleaner Air: Laws To Reduce Pollution

Air pollution is a pressing issue that has severe consequences for the environment and public health. To combat this, several laws have been passed worldwide, with one of the most influential being the Clean Air Act (CAA) in the United States. The CAA is a federal law that regulates air emissions from stationary and mobile sources, aiming to improve air quality and protect public health. Since its enactment in 1963, with amendments in 1970, 1977 and 1990, the CAA has played a pivotal role in reducing air pollution across the United States. The act defines the responsibilities of the Environmental Protection Agency (EPA) and empowers it to establish National Ambient Air Quality Standards (NAAQS) to safeguard public health and the environment. The CAA has been instrumental in tackling various air pollution problems and addressing emerging threats, making it a crucial piece of legislation in the ongoing battle for cleaner air.

The Clean Air Act

The 1990 amendments to the Clean Air Act were intended to address issues that had not been sufficiently tackled, including acid rain, ground-level ozone, stratospheric ozone depletion, visibility, and air toxics. These amendments also established a national operating permits program and strengthened enforcement to ensure better compliance with the Act. The Clean Air Act has been instrumental in reducing air pollution in the United States, with a 50% decline in emissions of key air pollutants since 1990.

National Ambient Air Quality Standards

The Clean Air Act, which was last amended in 1990, requires the US Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQS) for six principal pollutants ("criteria" air pollutants) that can be harmful to public health and the environment. These six major pollutants are ozone (O3), particulate matter (PM), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and lead (Pb).

The Clean Air Act identifies two types of national ambient air quality standards: primary standards and secondary standards. Primary standards provide public health protection, including for ''sensitive'' populations such as asthmatics, children, and the elderly. Secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings.

The Clean Air Act requires the EPA to review the standards and the science behind them periodically to determine whether changes are warranted. The EPA's NAAQS review process involves a comprehensive assessment of the relevant scientific literature, which is summarised in the Integrated Science Assessment (ISA). Based on the ISA, EPA staff perform a risk and exposure assessment, which is summarised 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 that could support retention or revision of the existing NAAQS, as well as 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. The committee's role is to ensure that the documents reflect the thinking of the scientific community and advise the EPA Administrator on technical and scientific aspects. Once all three documents are finalised, they are given to the EPA Administrator to select a proposed NAAQS, which is released for public comment. Following the comment period, the Administrator considers the comments received, makes changes to the proposed NAAQS if necessary, and publishes the final NAAQS.

The Clean Air Act has been instrumental in reducing air pollution in the United States over the past few decades. It has also played an important role in the US economy by reducing healthcare costs and absences from work or school. The Act has been amended several times since its enactment in 1970 to strengthen and expand its provisions, and it continues to be a critical tool in the fight against air pollution and its harmful effects on public health and the environment.

National Emissions Standards for Hazardous Air Pollutants

The Clean Air Act requires the U.S. Environmental Protection Agency (EPA) to regulate emissions of hazardous air pollutants (HAPs) that are harmful to human health or the environment. This regulation is known as the National Emission Standards for Hazardous Air Pollutants (NESHAP). HAPs are those pollutants that are known or suspected to cause cancer or other serious health issues, such as reproductive problems, birth defects, or adverse environmental effects.

There are two types of facilities covered by NESHAPs: major sources and area sources. Major sources have the potential to emit more than 10 tons per year of a single HAP or 25 tons per year of any combination of HAPs. Area sources, on the other hand, have the potential to emit less than 10 tons per year of a single HAP or 25 tons per year of any combination of HAPs. Many small businesses fall under the category of area sources.

NESHAPs are an additional federal standard that may apply to businesses regardless of whether they have an air permit. Due to the variety of NESHAPs, it is likely that at least one will apply to a given business. The EPA conducts inspections of facilities subject to NESHAP regulations to determine compliance. These inspections include reviewing reports and records, interviewing personnel, inspecting emission processes, and reviewing leak detection and repair methods.

Sources subject to NESHAPs are required to perform initial and ongoing performance tests to demonstrate compliance. Consistent with the EPA's Clean Air Act Stationary Source Compliance Monitoring Strategy, major sources generally receive a full compliance evaluation by the state or regional office at least once every two years.

NESHAP Source Categories include a wide range of industries, such as acrylic/modacrylic fiber, asphalt processing, auto and light-duty truck surface coating, benzene transfer and waste operations, boilers, brick and structural clay products manufacturing, carbon black production, and cellulose products manufacturing, to name a few.

New Source Performance Standards

The Clean Air Act, passed in 1970, is a federal law that gives the Environmental Protection Agency (EPA) the authority to regulate air pollutants and polluting industries in the United States. The Act has been amended several times since its inception, including in 1977, 1990, and 2022, to address emerging pollution threats and improve air quality.

The process of establishing NSPS involves several steps. Firstly, the type of emitting facility, such as a chemical plant or a petroleum refinery, is identified. Next, the appropriate type of pollutant control technology for each facility type is determined. This involves studying the plants, their technologies, and any available information. Finally, an allowed concentration of criteria pollutants, which is the upper limit of what can be emitted, is established.

The NSPS regulations cover a wide range of industrial categories, including:

• Electric arc furnaces and argon-oxygen decarburization vessels in steel plants
• Residential wood heaters
• Rubber tire manufacturing
• Glass manufacturing plants
• Petroleum refineries
• Stationary gas turbines
• Lead acid battery manufacturing
• Primary lead smelting
• Municipal solid waste landfills
• Coal preparation and processing plants

The NSPS, authorized by Section 111 of the Clean Air Act, are published in 40 CFR Part 60. These standards play a crucial role in ensuring that new industrial facilities incorporate the latest pollution control technologies, contributing to the overall improvement of air quality and the protection of public health.

Acid Rain Program

The Acid Rain Program (ARP) was established under Title IV – Acid Deposition Control, which requires major emission reductions of sulfur dioxide (SO2) and nitrogen oxides (NOx), the primary contributors to acid rain, from the power sector. The SO2 program sets a permanent cap on the total amount of SO2 that may be emitted by electric generating units (EGUs) in the contiguous United States. The program was phased in, with the final 2010 SO2 cap set at 8.95 million tons, about half the emissions from the power sector in 1980.

ARP was the first national cap-and-trade program in the country and introduced a system of allowance trading that uses market-based incentives to reduce pollution. This provides regulated sources with the flexibility to select the most cost-effective approach to reducing emissions, and has proven to be a highly effective way to achieve emission reductions, meet environmental goals, and improve human health.

The program has two phases. Phase I, which began in 1995, affected 263 units at 110 mostly coal-burning electric utility plants located in 21 eastern and midwestern states. Phase II, which began in 2000, added more units to the Acid Rain Program, encompassing over 2,000 units in total.

Reductions in SO2 emissions are facilitated through a market-based cap-and-trade system. Under this system, the EPA sets a cap on overall emissions. SO2 allowances are then allocated to affected units serving generators greater than 25 megawatts. Each allowance permits a unit to emit one ton of SO2. Sources may choose from several options to reduce emissions. They can sell or bank excess allowances if they reduce emissions and have more than they need, or purchase allowances if they are unable to keep emissions below their allocated level.

The Acid Rain Program has achieved significant emission reductions. Together with more recent power sector regulations, including the Cross-State Air Pollution Rule (CSAPR) programs, and a rapidly changing energy sector, the ARP has helped deliver annual SO2 reductions of over 95% and annual NOX emissions reductions of over 89%. Wet sulfate deposition – a common indicator of acid rain – dropped by more than 70% between 1989-1991 and 2020-2022.

A 2021 study found that the "Acid Rain Program caused lasting improvements in ambient air quality," reducing mortality risk by 5% over 10 years.

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