Emissions

EPA proposes further tightening PM2.5 air quality standards

The proposed change would tighten the primary annual PM2.5 standard from a level of 12 micrograms per cubic meter to a level between 9 and 10 micrograms per cubic meter.

EPA proposes further tightening PM2.5 air quality standards
(U.S. EPA headquarters. Credit: flickr)

The U.S. Environmental Protection Agency said it plans to strengthen its ambient air quality standard (NAAQS) for fine particle pollution, also known as PM2.5. 

EPA said it would take comments on strengthening the primary annual PM2.5 standard from a level of 12 micrograms per cubic meter to a level between 9 and 10 micrograms per cubic meter.

It said the tighter standard reflected the latest health data and scientific evidence. The agency said it also would take comments on the full range (between 8 and 11 micrograms per cubic meter) included in a recent Clean Air Scientific Advisory Committee (CASAC) report.

EPA said that since it completed its last review of the PM NAAQS in 2012, “thousands of new scientific studies have demonstrated the dangers of soot exposure.” 

EPA estimated that if finalized, a strengthened primary annual PM2.5 standard at a level of 9 micrograms per cubic meter could prevent up to 4,200 premature deaths per year. 

EPA said it was also proposing to revise other aspects related to the PM standards – such as monitoring requirements and the Air Quality Index (AQI) – in a bid to help states and Tribal Nations meet the revised standards. It proposed retaining the primary 24-hour PM2.5 standard of 35 micrograms per cubic meter, while taking comment on revising the level to as low as 25 micrograms per cubic meter. 

In June 2021, EPA said it would reconsider a Trump-era decision to retain the 2012 PM2.5 standards. At the time, it said that available scientific evidence and technical information indicated that the standards “may not be adequate to protect public health and welfare.” 

EPA said that in developing its new proposal, which was released January 6, it considered the best available science and technical information, including an Integrated Science Assessment and updated Policy Assessment.

Tags