On December 7, the U.S. Environmental Protection Agency (EPA) announced it will retain, without revision, the nation’s existing National Ambient Air Quality Standards (NAAQS) for particulate matter (PM). The EPA will retain the annual and 24-hour primary (health) and secondary (welfare) standards for fine particles (PM2.5)) and course particles (PM10). The decision comes after the agency reviewed and considered more than 60,000 public comments on the proposal. An EPA Fact Sheet on the decision can be viewed here.
The Clean Air Act requires EPA to set two types of National Ambient Air Quality Standards for particle pollution: primary standards – to protect public health, and secondary standards – to protect public welfare. The law requires that primary standards be “requisite to protect public health with an adequate margin of safety,” including the health of sensitive groups of people. For PM, scientific evidence suggests that people with heart or lung disease, children and older adults and nonwhite populations are at higher risk.
NAAQS can have a significant impact on county governments. Under the Clean Air Act, states and counties serve as co-regulators with the federal government and are ultimately responsible for the implementation of new and existing air quality standards. As the incoming Biden Administration considers potential future EPA regulations, this rule may be reversed, and revised air quality standards may be implemented.