EPA Tightens Air Quality Limits for Particulate Matter Pollution

States will need to tighten up their compliance with soot limits under a new rule finalized by the EPA on Wednesday.

The Environmental Protection Agency decreased the amount of allowable particulate matter, or PM 2.5, permitted in the ambient air. Under the final rule, the EPA tightened the allowable threshold from 12 to 9 micrograms per cubic meter daily, the first change in the limits since 2012.

This “action is a critical step forward that will better protect workers, families and communities from the dangerous and costly impacts of fine particle pollution,” EPA administrator Michael Regan told press on Tuesday. “The science is clear, soot pollution is one of the most dangerous forms of air pollution and it’s linked to a range of serious and potentially deadly illnesses.”

Particulate matter is one of six harmful pollutants that administrations regulate through National Ambient Air Quality Standards. States submit plans for approval for each of the limits, which are supposed to be regularly reviewed and updated to protect public health.

Environmental and health groups hailed the finalized limits, which they say is a crucial update for a pollutant that is getting worse with global warming impacts.

“This will help save lives today and improve the health of generations to come,” Natural Resources Defense Council president Manish Bapna said in a statement. “Soot puts tens of millions of Americans at risk, disproportionately harming low-income communities and people of color.”

Exposure to PM 2.5 can result in a gamut of adverse health effects, from short-term lung distress to heart disease. The EPA estimates $46 billion in net health benefits in 2032 stemming from the new rules.

Increased wildfires made worse by climate change spread PM 2.5 across the US every year, which advocates say necessitates stricter standards—while industry argues the opposite.

Largely GOP-led states and industry trade groups will likely wage legal war over the standards, which they have fought hard to quash in public commentary, reports, and even national television ads. Critics say stricter limits in addition to uncontrollable fires will push big chunks of the country out of clean air law attainment.

“The EPA’s decision to significantly lower the current standards will have wide ranging negative implications well beyond the mining industry -- impeding permitting for factories, energy and infrastructure projects,” according to a statement from Rich Nolan, president of the National Mining Association.