WASHINGTON, DC – January 1, 2023 – The United States’ Clean Air Act (CAA) is the foremost air quality law to reduce and control air pollution in our country. It was first passed in 1963. The law is administered by the U.S. Environmental Protection Agency (EPA). The agency sets standards for the maximum concentrations of pollutants in outdoor air and for maximum emissions of hazardous air pollutants from specific industrial sources. After the pollution standards are set, the state and local governments have to develop implementation plans to best achieve these standards. These plans are directed at either a major source or an “area” source. The CAA has been frequently challenged in court by groups seeking stricter guidelines and by other groups seeking less regulation.
The EPA regulates 6 ‘criteria’ air pollutants by using human heath-based and/or environmentally-based criteria data. The agency develops guidelines for the maximum concentration allowable in outdoor air. Five gases and particulate matter (PM) comprise these pollutants. The five gases are carbon monoxide, lead, nitrogen oxides, ground-level ozone and sulfur oxides. PM is a mixture of solid particles and liquid droplets in the air. The EPA only regulates inhalable particles 10 micrometers or smaller. Large particles, like dust, pollen and mold, are about 2.5 to 10 micrometers in width, called PM10 particles. Fine particles, derived from burning fuels and organic compounds, measure less than or equal to 2.5 micrometers in width, called PM2.5 particles. These particles are one thirtieth the width of a human hair. They usually form in the air following a chemical reaction between nitrogen and sulfa-based criteria gases.
The PM2.5 particles, also called soot, pose a greater risk to human health than the PM10 particles. Soot is linked to heart and lung disease and with early death. It also can adversely affect fetal health and is associated with childhood asthma. Breathing PM has been associated with 32 thousand deaths in the U.S. in 2020, according to a Lancet journal review. Many are related to fossil fuel combustion. Low-income communities and communities of color disproportionately are situated closer to highways and industry in urban areas, the major sources of particle pollution. Other vulnerable groups include outdoor workers, children, seniors, and persons with heart and lung disease.
In January, the EPA has proposed reducing the maximum concentration of PM2.5 from 12 micrometers per cubic meter of air to between 9 and 10. This is based on the daily averages over the course of a year. The agency is taking public comment on these proposed limits for 60 days after the proposal is entered into the Federal Registry. The Clean Air Scientific Advisory Committee, the American Lung Association, the advocacy group Clean Air Now and the Union of Concerned Scientists are in favor of even lower standards, 8 micrograms per cubic meter of air, in order to better protect vulnerable groups that live closer to the sources of pollution.
Harold Wimmer, the president of the American Lung Association said to USA Today, “Inadequate standards leave too many communities behind. Strong particulate matter standards are needed to protect public health and further environmental justice.”
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Contact: Dr. Dick Needleman, Health reporter, 103.3 AshevilleFM, [email protected]
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