Air Pollution Crisis: Exceeding Federal Safety Standards

Air pollution is a pressing issue that poses significant risks to public health and the environment. Particle or soot pollution, in particular, has been linked to a range of serious and potentially fatal illnesses. To safeguard the well-being of citizens, federal governments worldwide have established air quality standards, setting limits on the concentration of harmful particles in the air. However, despite these regulations, some areas still struggle to meet the safety standards, leading to detrimental health impacts on their residents. This situation underscores the urgent need for effective emission reduction strategies and heightened awareness of the dangers posed by air pollution.

The Clean Air Act requires EPA to set National Ambient Air Quality Standards

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

The Clean Air Act identifies two types of national ambient air quality standards: primary standards and secondary standards. Primary standards aim to protect public health, including sensitive populations such as asthmatics, children, and the elderly, by ensuring an adequate margin of safety. On the other hand, secondary standards focus on public welfare protection, safeguarding against damage to the environment and various aspects of human life, such as soils, water, crops, animals, wildlife, property, transportation, and personal comfort.

The EPA periodically reviews and revises these standards to incorporate the latest science and ensure their effectiveness. For instance, the EPA proposed revisions to the data handling procedures for PM2.5 standards, including computations and measurements for comparing and meeting the standards. Additionally, the EPA has the responsibility to establish emission standards for "major sources" and "area sources". "Major sources" refer to stationary sources emitting or capable of emitting high levels of hazardous air pollutants, while "area sources" encompass any stationary sources that are not classified as major.

State, local, and tribal agencies play a crucial role in implementing the NAAQS by developing emission reduction strategies, plans, and programs. The Menu of Control Measures (MCM) provides these agencies with existing emission reduction measures and relevant information on their efficiency and cost-effectiveness. The Clean Air Act also addresses the prevention of pollution increases from motor vehicles and industrial plants, encouraging the use of the best available technology for new stationary sources while allowing less stringent standards for existing ones.

The EPA proposed to revise data handling procedures

The EPA's approach to establishing the level of the standards in 1997 was criticised by a panel as "an unconstitutional delegation of legislative authority". The panel remanded the rule to the EPA, stating that the agency lacked a "determinate criterion for drawing lines" to set the standards. In response, the EPA placed greater weight on US and Canadian studies using PM2.5 measurements in its assessment of the evidence.

The revised PM2.5 standards reflect consideration of a quantitative risk assessment that estimates the public health risks likely to remain upon meeting the current and alternative standards. The Administrator concluded that the current primary PM2.5 standards were insufficient to protect public health with an adequate margin of safety, as required by the CAA. Therefore, revisions were warranted to increase public health protection.

The EPA also proposed to update several aspects of the monitoring regulations, including requiring the relocation of a small number of PM2.5 monitors to be collocated with measurements of other pollutants (e.g. nitrogen dioxide, carbon monoxide) in the near-road environment. These proposals aimed to prevent fine particle concentrations that have been demonstrated to be harmful and to protect public health and welfare, as required by the Clean Air Act.

EPA strengthened National Ambient Air Quality Standards for Particulate Matter

On February 7, 2024, the Environmental Protection Agency (EPA) strengthened the National Ambient Air Quality Standards (NAAQS) for particulate matter (PM NAAQS) to protect Americans from harmful health impacts, such as heart attacks and premature death. Particle or soot pollution is a dangerous form of air pollution, and scientific studies link it to a range of serious and sometimes deadly illnesses.

The EPA set the level of the primary (health-based) annual PM2.5 standard at 9.0 micrograms per cubic meter, providing increased public health protection. This decision was based on a review of the air quality criteria and the consideration of a quantitative risk assessment, which estimated the public health risks likely to remain if only the current standards were met. The EPA also proposed to revise data handling procedures and update monitoring regulations, specifically requiring the relocation of a small number of PM2.5 monitors to be collocated with measurements of other pollutants in the near-road environment.

The EPA's strengthened standards address fine particle concentrations that have been demonstrated to be harmful, as well as lower fine particle concentrations that may pose an unacceptable risk of harm, even if the nature or degree of the risk is not precisely identified. The EPA considered factors such as the nature and severity of health effects, the size of sensitive populations, and the degree of uncertainties when making these changes.

The EPA is also revising the Air Quality Index to improve public communications about the risks from PM2.5 exposures and is making changes to enhance the protection of air quality in communities disproportionately affected by air pollution. These changes are consistent with the EPA's goal of providing increased public health protection, as required by the Clean Air Act, and reflect the advances in scientific knowledge on the effects of pollutants on public health and welfare.

EPA retained primary and secondary NAAQS

The Clean Air Act requires the EPA to set National Ambient Air Quality Standards (NAAQS) for six principal pollutants, or "criteria pollutants", that are common in outdoor air and considered harmful to public health and the environment. These pollutants come from numerous and diverse sources. The statute established two types of national air quality standards: primary and secondary standards.

The primary standards are designed to provide public health protection, including protecting the health of "sensitive" populations such as asthmatics, children, and the elderly. The EPA is retaining the current 24-hour PM10 standard, with a level of 150 μg/m3, to continue to provide protection against effects associated with short-term exposure to PM10-2.5, including premature mortality and increased hospital admissions and emergency department visits.

The secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings. The EPA's approach to establishing the level of the standards, both for PM and for the ozone NAAQS promulgated on the same day, was deemed to have effected “an unconstitutional delegation of legislative authority”. The EPA proposed to revise the data handling procedures consistent with the revised primary and secondary standards for PM2.5, including the computations necessary for determining when these standards are met and the measurement data that are appropriate for comparison to the standards.

State, local, and tribal agencies can use this information to develop emission reduction strategies, plans, and programs to ensure they attain and maintain the NAAQS. The Menu of Control Measures (MCM) provides these agencies with existing emission reduction measures and relevant information concerning the efficiency and cost-effectiveness of the measures.

Federal programs provide for nationwide reductions in emissions of PM

The Clean Air Act, last amended in 1990, requires the 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 pollutants include particles, ozone, lead, carbon monoxide, nitrogen dioxide, and sulfur dioxide. The EPA has issued emissions standards to control toxic emissions from all 174 categories of major sources, such as chemical plants and oil refineries, as well as from 68 categories of small "area" sources that represent 90% of the worst urban toxic pollutants.

The EPA has taken initial steps to limit emissions that cause climate change and ocean acidification, prompting the deployment of clean technologies and innovations that reduce emissions and control costs. The Clean Air Act programs have lowered levels of the six common pollutants and numerous toxic pollutants. Between 1970 and 2020, combined emissions of these pollutants dropped by 78%.

The EPA has also established the National Ambient Air Quality Standards (NAAQS) for particulate matter, aiming to protect public health and prevent harmful fine particle concentrations. The EPA proposed revisions to the data handling procedures for PM2.5 standards, including computations and measurements to determine when the standards are met.

Furthermore, the EPA has implemented rules and initiatives to reduce emissions of methane and other harmful air pollutants from the oil and natural gas sector. The final action includes New Source Performance Standards and Emissions Guidelines to reduce methane and smog-forming volatile organic compounds from new, modified, and reconstructed sources. The EPA has also established the HFC Allocation program, aiming to phase down U.S. production and consumption of HFCs by 85% from historic levels by 2036.

Additionally, the EPA has issued the Multi-Pollutant Emissions Standards for Model Years 2027 and Later Light-Duty and Medium-Duty Vehicles, setting new standards to reduce harmful air pollutant emissions from these vehicles. These standards build upon the EPA's previous efforts to reduce greenhouse gas emissions from passenger cars and light trucks.

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