EPA Says It Will Reconsider Trump Administration’s Decision On Particulate Matter

The Environmental Protection Agency (EPA) on June 10 announced that it will reconsider the Trump Administration’s decision to retain the particulate matter (PM) National Ambient Air Quality Standards (NAAQS).

EPA is reconsidering the December 2020 decision “because available scientific evidence and technical information indicate that the current standards may not be adequate to protect public health and welfare, as required by the Clean Air Act,” it said in a news release.

Particulate matter includes fine particles, which are 2.5 micrometers in diameter and smaller. They can be emitted directly from a variety of sources, including vehicles, smokestacks, and fires. They also form when gases emitted by power plants, industrial processes, and gasoline and diesel engines react in the atmosphere.

Coarse particles, which have diameters between 2.5 and 10 micrometers, include road dust that is kicked up by traffic, some agricultural operations, construction and demolition operations, industrial processes, and biomass burning.

EPA has regulated particle pollution since 1971 and has revised the standards four times -- in 1987, 1997, 2006 and 2012.

EPA’s 2020 policy assessment concluded that the scientific evidence and information support revising the level of the annual standard for the PM NAAQS to below the current level of 12 micrograms per cubic meter while retaining a 24-hour standard.

The agency received numerous petitions for reconsideration as well as lawsuits challenging the December 2020 final action.

EPA said that as part of its move to reconsider the decision to retain the particulate matter NAAQS, the agency will develop a supplement to a 2019 Final Integrated Science Assessment that will take into account the most up-to-date science, including new studies in the emerging area of COVID-related research.  

The supplement will be reviewed at a public meeting by the chartered Clean Air Scientific Advisory Committee (CASAC), supported by a particulate matter review panel of scientific experts on the health and welfare impacts of PM.

The CASAC and the PM panel will also review a revised policy assessment and formulate advice to the Administrator.

The public will have opportunities to comment on these documents during the CASAC review process, as well as to provide input during the rulemaking through the public comment process and public hearings.

EPA expects to issue a proposed rulemaking this summer and a final rule in Spring 2023.

For more information on the NAAQS review process and documents related to prior PM NAAQS reviews, visit https://www.epa.gov/naaqs/particulate-matter-pm-air-quality-standards.

In June 2020, APPA and the National Rural Electric Cooperative Association submitted joint comments advocating for EPA to retain the annual PM 2.5 NAAQS.