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EPA Integrated Science Assessments: Helping Fight Air Pollution

EPA's Integrated Science Assessments deliver the science to support the Clean Air Act, one of the most beneficial federal programs in the nation.

Young man sitting on rock looking out into a forest.

The average American breathes more than 11,000 liters of air—enough to fill a tanker truck—every day. Understanding this, it's easy to see why air pollution is of such concern. Forty years ago, air pollution was so prevalent in some cities that you may have complained of burning eyes from ozone pollution, or the air was so visibly polluted that you couldn't see across the city.

Back then, Americans were exposed daily to potentially dangerous amounts of ground-level ozone and other pollutants, symptoms of which often included airway irritation and increased susceptibility to illnesses such as asthma and bronchitis.

Today, large segments of the population are breathing cleaner, healthier air—a direct result of the Clean Air Act and the scientific framework put in place to guide actions taken to protect human health, the Act's primary goal. That framework is built around EPA's National Ambient Air Quality Standards (NAAQS) and the Integrated Science Assessments (ISAs) that deliver the science supporting those standards.

The landmark Clean Air Act (CAA), enacted by Congress in 1970, was one of the federal Government's first efforts at regulating air quality in order to protect human health and the environment. Congress created the EPA soon afterward, in part to implement the new law.

Last amended in 1990, the CAA requires EPA to develop NAAQS for six criteria pollutants: carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide. The standards set permissible limits for each pollutant that must be met in order to protect public health—including the health of sensitive groups such as asthmatics, children, and aging adults—as well as public welfare, including protection against damage to animals, crops, and buildings.

During the first 20 years of the Clean Air Act, health benefits increased steadily (PDF) (3 pp, 26K, About PDF) from 1970 to 1990. In the year 1990, clean air programs prevented: 205,000 premature deaths; 672,000 cases of chronic bronchitis; 21,000 cases of heart disease; 843,000 asthma attacks; 189,000 cardiovascular hospitalizations; 10.4 million lost I.Q. points in children from lead reductions; and 18 million child respiratory illnesses.

It is because of these health improvements that the ISAs for each criteria pollutant and the NAAQS they support are essential. Children, aging adults, and people with certain diseases are particularly at risk for pulmonary, cardiac, vascular, and neurological impairments as a result of long-term air pollution exposure.

As required by the CAA, EPA conducts periodic reviews of the six criteria air pollutants and develops ISAs that summarize the science related to the health and ecological effects caused by the pollutants. To achieve this, EPA scientists conduct a comprehensive review of the policy-relevant scientific literature published since the last review, ensuring that each ISA is based on the latest scientific information.

After the best available science has been evaluated and synthesized, each ISA is vetted through a rigorous peer review process, including evaluation by the independent Clean Air Scientific Advisory Committee (CASAC). Each assessment is also made available for a public comment period. The end result is rigorous, science-based assessments to guide the development of NAAQS for each criteria pollutant.

"We at the American Lung Association rely on the EPA's Integrated Science Assessments for the most thorough review of the available research on the criteria pollutants," says Janice Nolen, Assistant Vice President of National Policy and Advocacy at the American Lung Association Exit EPA Disclaimer. Ellen Porter of the National Park Services' Air Resources Division adds, "ISA data on human and ecosystem impacts are used to establish benchmarks to rate air quality conditions in parks as either good, moderate, or of significant concern. These condition assessments are used to help identify national parks most at risk from air pollution."

Thanks to the ISAs and NAAQS, the Clean Air Act has made significant and far-reaching impacts on the health and well being of the American public, including longer life expectancies Exit EPA Disclaimer, healthier communities, and more sustainable ecosystems.

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