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The Environmental Protection Agency announced on Friday more aggressive air quality standards for particulate matter, pollutants small enough to be inhaled and cause respiratory illness and other disease.

The agency’s new rules would help clean the nation’s air and bring it more in line with the past decade of research on the harmful effects of particulate matter. “Neither an individual’s skin color nor the wealth of their ZIP code should determine whether they have clean air to breathe, safe water to drink, or healthy environments in which their children can play,” EPA Administrator Michael Regan said in May, the Washington Informer reported.


But health advocates say the agency’s proposed change isn’t strong enough to protect the public. 

“It seems to me pretty clear that this probably doesn’t go far enough,” said Matt Altman, an asthma specialist at the University of Washington who has studied the effects of air pollution on children with the asthma.

The EPA’s rule comes as asthma and other chronic diseases, particularly respiratory ones, are steadily rising. Chronic obstructive pulmonary disease is a leading cause of death in the U.S., and asthma is one of the most common chronic conditions in children.


“Particulate matter is widespread and we know that it’s deadly. The science is very clear,” said Laura Kate Bender, national assistant vice president of Healthy Air at American Lung Association. 

This is the first time in a decade that the National Ambient Air Quality Standards for particulate matter will be changed, since in 2020 federal regulators under the Trump administration opted to keep rules from 2013 (a decision that drew criticism and lawsuits). By law, the EPA’s air quality standards must be reviewed every five years. Many are touting this latest development as a win for the public.

And yet, even under a new administration that has said it will center environmental justice, critics say the EPA is proposing maximum levels of pollution above what years of research deems safe.

Particulate matter refers to tiny particles that float through the air and can be breathed in, residue from dusty manufacturing sites and burns, as well as other sources. Two types of particulate matter are of significant concern to the EPA: particles with a diameter of 10 microns or less, called PM10, and those 2.5 microns or less in diameter (PM2.5). 

Both have been shown to cause short-term and long-term harm, and are especially risky for pregnant people, babies and children, older adults, and people with lung or heart disease. Fine particles, those 2.5 microns or less, are especially dangerous, and can increase chances of premature death, heart attacks, and strokes.

People who live in low-income communities and people of color are disproportionately affected by particulate-matter-laden air, a result of neighborhoods located near major polluters, like factories, ports, and highways.

Much of the debate around these air quality rules comes down to two numbers that dictate how many bits of pollution can be in a cubic meter of air. One number sets an annual average for how much particulate pollution can be in the air, and another sets a higher, 24-hour average, which accounts for spikes and lulls. Both of these numbers are used by federal authorities to monitor air quality, send out alerts, and crack down on major polluters. Because the air quality standards are governed by the Clean Air Act, the EPA is legally required to act based narrowly on up-to-date scientific evidence — whatever is in the best interest of public health. 

The current standard, from 2013, says there can be up to 12 micrograms of fine particulate matter (the smaller particles) per cubic meter on an average day, annually. Both the EPA and its independent panel of scientific advisers, the Clean Air Scientific Advisory Committee, as well as many health and environmental groups, agreed that number must drop to protect people’s health. The EPA suggests 9 to 10 micrograms per cubic meter in its proposal.

But the consensus ends there. The American Lung Association and other groups are pushing for a maximum of 8 micrograms of fine particles as the annual standard. 

Further, the EPA’s proposed policy suggests keeping the same standards otherwise. That means, in a 24-hour span, there could be up to 35 micrograms per cubic meter of air for fine particles, and 150 micrograms per cubic meter for larger particles.

Critics argue that is much too high, noting that 25 to 30 micrograms of PM2.5 per cubic meter in a day was the range recommended by the independent advisory group in a report last year. 

Things could still change. In a fact sheet released Friday, the EPA suggested it is considering the lower levels pushed by interest groups, and is soliciting feedback.

Altman’s research into children’s asthma attacks in urban areas suggests even a few days at 25 micrograms of fine particles could have deleterious effects on some vulnerable groups. “Potentially levels even below 25 could be harmful,” he said. “Lower is needed. Exactly how low, I guess to be determined.” 

His study on children with nonviral asthma pointed to PM2.5 as a major driver of inflammation in children’s airways — meaning the particles could be driving cellular changes that would make many asthma therapies ineffective.

“In a perfect world, we just decrease the exposure, but as we see in the EPA guidelines, you can’t just do that,” he said.

The EPA will receive public comments for 60 days before finalizing its new rules, so the standards could still change. Pushback from industry groups that find the standards heavy-handed is expected. The EPA’s own report estimated it would cost upward of $65 billion each year in the 2020s to meet Clean Air Act amendment rules, but it also said that economic benefits would far outweigh those costs.

Standard changes could “result in as many as 4,200 avoided premature deaths and 270,000 avoided lost workdays in 2032,” according to EPA estimates.

The draft policy also includes a new proposal, which would amend air quality monitoring data and criteria to account for how close at-risk populations are to the sources of fine particulate matter pollution. Research has shown great disparities in air quality across the nation, even during the pandemic lockdowns, when fewer cars were on the roads.

The new standards, while a step in the right direction, won’t apply evenly to all places because they are regional averages, said Gaige Kerr, a research scientist who studies air quality at George Washington University. “Unfortunately, many of the areas where concentrations fall above this average of 9-10 ug/m3 are marginalized, racialized, and minoritized communities,” he said. “The fact that these communities still are disproportionately exposed, despite decades of macro-level progress across the U.S. thanks to the Clean Air Act and its amendments, suggests that more targeted interventions are needed to specifically ratchet down concentrations in the most overburdened communities.”

In its annual “State of the Air” report, the American Lung Association found Americans experienced more days of “very unhealthy” and “hazardous” air quality between 2019 and 2021 than at any other time in the past two decades. 

“We keep seeing with emerging science that this pollutant is dangerous in more ways and at lower levels than previously thought,” Bender said. 

STAT’s coverage of chronic health issues is supported by a grant from Bloomberg Philanthropies. Our financial supporters are not involved in any decisions about our journalism.

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