EPA tightens standard for fine particles

For the first time in over a decade, the US Environmental Protection Agency has updated the standard for fine particulate matter, known as PM_2.5. The new rule lowers the acceptable limit of PM_2.5 from an annual average of 12 μg/m³ to 9 μg/m³.

PM_2.5 is “one of the most dangerous forms of pollution,” EPA administrator Michael S. Regan said during a call with reporters. Small enough to penetrate deep into the lungs, these particles are linked to a slew of adverse health effects, including asthma, lung disease, and heart attacks.

According to the EPA, the updated standard will prevent 800,000 cases of asthma, 4,500 premature deaths, and 290,000 lost workdays by 2032. The action “is a critical step forward that will better protect workers, families, and communities from the dangerous and costly impacts of fine particle pollution,” Regan said.

Environmental groups and health organizations celebrated the news. “EPA’s final standards will save thousands of lives, help advance environmental justice, and allow us all to breathe a little easier,” Peter Zalzal, associate vice president for clean air strategies at the Environmental Defense Fund, says in a statement.

In a separate statement, Harold Wimmer, CEO of the American Lung Association, says, “Strengthening the annual particle pollution standard will make an important difference, especially for communities near a pollution source like a power plant or a busy road.”

But Wimmer says he is disappointed that the new PM_2.5 standard falls short of the 8 μg/m³ recommended by the American Lung Association and some other groups. “An annual standard of 8 μg/m³ would save significantly more lives, especially in Black communities,” he says. In the US, people of color are disproportionately exposed to higher levels of PM_2.5 pollution than White people are (Sci. Adv. 2021, DOI: 10.1126/sciadv.abf4491).

Many groups also recommended that the EPA lower its 24 h standard to 25 μg/m³. Even so, the EPA decided to keep the current 24 h standard of 35 μg/m³, saying it didn’t see sufficient evidence to revise it.

Although some groups are frustrated that the new standards are still too high, industry groups say they are too low. In a statement, the American Chemistry Council, which represents the US chemical industry, says the new standards will make permitting important projects more challenging, which will in turn “hinder our nation’s ability to build new infrastructure, expand manufacturing, and grow our economy.”

Similarly, Jay Timmons, CEO of the National Association of Manufacturers, says in a press release that the new standard “takes direct aim at manufacturing investment and job creation.”

Regan challenged this idea, noting that since 2000, outdoor PM_2.5 concentrations have decreased by 42%, even as the US gross domestic product increased by 52%. The EPA also notes that for every $1 spent on reducing PM_2.5 levels by 2032, the US could gain as much as $77 in human health benefits.