air pollution the release of dirty waste into the environment

January 6, 2023

The U.S. Environmental Protection Agency (EPA) proposal to strengthen a key national ambient air quality standard (NAAQS) for fine particle pollution, also known as PM2.5, to better protect communities, including those most overburdened by pollution. Fine particles, sometimes called soot, can penetrate deep into the lungs and can result in serious health effects that include asthma attacks, heart attacks and premature death – disproportionately affecting vulnerable populations including children, older adults, those with heart or lung conditions, as well as communities of color and low-income communities throughout the United States. These particles may be emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks, or fires; other 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.

The EPA’s proposed rule, however, overlooks the recommendations of its clean air scientific advisory committee, which suggested a standard of eight micrograms per cubic meter for soot. This is key to many elected officials, environmental groups and activists.

EPA’s proposal will specifically take comment on strengthening the primary (health-based) annual PM2.5 standard from a level of 12 micrograms per cubic meter to a level between 9 and 10 micrograms per cubic meter, reflecting the latest health data and scientific evidence; the Agency is also taking comment on the full range (between 8 and 11 micrograms per cubic meter) included in the Clean Air Scientific Advisory Committee’s (CASAC) latest report.

EPA will accept public comment for 60 days after the proposal is published in the Federal Register. EPA will also conduct a virtual public hearing over several days for this proposed rulemaking, with the hearing beginning at 11:00 am Eastern Time and concluding at 7:00 pm ET each day.  EPA will begin pre-registering speakers for the hearing upon publication of the announcement of the public hearings in the Federal Register.  Additional information will also be made available on the National Ambient Air Quality Standards (NAAQS) for PM webpage.

“Our work to deliver clean, breathable air for everyone is a top priority at EPA, and this proposal will help ensure that all communities, especially the most vulnerable among us, are protected from exposure to harmful pollution,” said EPA Administrator Michael S. Regan. “This proposal to deliver stronger health protections against particulate matter is grounded in the best available science, advancing the Biden-Harris Administration’s commitment to scientific integrity and a rigorous scientific process.”

Since EPA completed its last review of the PM NAAQS in 2012, thousands of new scientific studies have demonstrated the dangers of soot exposure. Strengthening the primary annual PM2.5 standard is expected to address disparities and would result in significant public health benefits. EPA estimates that if finalized, a strengthened primary annual PM2.5 standard at a level of 9 micrograms per cubic meter, the lower end of the proposed range, would prevent:

  • up to 4,200 premature deaths per year;
  • 270,000 lost workdays per year;
  • result in as much as $43 billion in net health benefits in 2032.

The start isn’t enough to truly protect environmental justice communities from the harms of the chemicals.

EPA says they will work closely with state, local, and Tribal air agencies to implement the revised primary annual PM2.5 standard when finalized. Today’s proposal is the latest in a broader suite of programs under President Biden’s leadership to reduce air pollution that threatens communities.  These programs include the proposed Good Neighbor Plan to address smog that affects downwind states, rules to address air pollution from oil and gas operations, including methane pollution, and other critical rules to reduce emissions from power plants and the transportation sector, such as the recently finalized Clean Trucks Rule that will slash smog- and soot-forming pollution from heavy-duty trucks. Additionally, funding from the President’s Bipartisan Infrastructure Law and the Inflation Reduction Act aimed at cutting pollution from school buses and trucks, port operations, and electricity generation are also expected to reduce soot and other harmful air pollutants.

EPA is also proposing to revise other aspects related to the PM standards – such as monitoring requirements and the Air Quality Index (AQI) – that will help states and Tribal Nations meet the revised standards while making significant strides toward protecting the health of all people, including at-risk populations. The Agency is proposing to retain the primary 24-hour PM2.5 standard of 35 micrograms per cubic meter, while taking comment on revising this level to as low as 25 micrograms per cubic meter. 

After reviewing comments, the Agency plans to issue final standards later this year.

More information on particulate matter.


The Clean Air Act requires EPA to set two types of NAAQS: health-based standards, called primary standards, and standards to protect public welfare, called secondary standards. Based on the scientific evidence and technical information, EPA has set two primary standards for PM2.5, which work together to protect public health: the annual standard, which EPA is proposing to revise, and a 24-hour standard, which the Agency is proposing to retain. EPA also is proposing to retain the current primary 24-hour standard for PM10, which provides protection against coarse particles. In addition, the Agency is proposing to retain the secondary standards for both PM2.5 and PM10 at this time.

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