Originally published on EPA.
This week, EPA announced that it will reconsider the previous administration’s decision to retain the particulate matter (PM) National Ambient Air Quality Standards (NAAQS), which were last strengthened in 2012. 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.
“The most vulnerable among us are most at risk from exposure to particulate matter, and that’s why it’s so important we take a hard look at these standards that haven’t been updated in nine years,” said EPA Administrator Michael S. Regan. “EPA is committed to ensuring this review, and other upcoming NAAQS reviews, reflect the latest science and public health data.”
The strong body of scientific evidence shows that long- and short-term exposures to fine particles (PM2.5) can harm people’s health, leading to heart attacks, asthma attacks, and premature death. Large segments of the U.S. population, including children, people with heart or lung conditions, and people of color, are at risk of health effects from PM2.5. In addition, a number of recent studies have examined relationships between COVID and air pollutants, including PM, and potential health implications. While some PM is emitted directly from sources such as construction sites, unpaved roads, fields, smokestacks or fires, most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industrial facilities and vehicles.
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 the 24-hour standard. The agency also received numerous petitions for reconsideration as well as lawsuits challenging the December 2020 final action.
EPA will move expeditiously to reconsider the decision to retain the particulate matter NAAQS, in a manner that adheres to rigorous standards of scientific integrity and provides ample opportunities for public input and engagement. As part of this process, the agency will develop a supplement to the 2019 Final Integrated Science Assessment (ISA) that will take into account the most up-to-date science, including new studies in the emerging area of COVID-related research.
This 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. As with all reviews, 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 on any proposed decision.
EPA expects to issue a proposed rulemaking in Summer 2022 and a final rule in Spring 2023, following an open, transparent process with opportunities for public review and comment. In accordance with Executive Orders and guidance, the agency will be considering environmental justice during the rulemaking process.
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