The National Association of Manufacturers and other business groups are asking the U.S. Supreme Court to review and reverse a lower court decision that allowed the Environmental Protection Agency’s tougher air quality standard for fine particulate matter to stand.
In 2024, the EPA lowered the Afor PM2.5 from 12 micrograms per cubic meter to 9. NAM and other business groups challenged the rule change, arguing EPA lacked the authority to change the standards without a proper review or outside the regular time frame for reconsideration.
The U.S. Court of Appeals for the District of Columbia Circuit upheld the EPA standard in June, prompting NAM and other plaintiffs in the case to file a petition Aug. 28 asking the U.S. Supreme Court to decide whether to hear the case.
According to NAM analysis, a PM2.5 standard of 9 threatens at least 474 manufacturing projects announced in the United States since Jan. 1, 2025—representing nearly $1 trillion in investment and more than 122,000 American jobs. Five of those projects are in New Jersey.
“Manufacturers have fought this rule from the beginning because the consequences for investment, growth and American competitiveness are enormous: investment, jobs and America’s ability to compete,” said NAM Chief Legal Officer Linda Kelly.
The Clean Air Act requires the EPA to conduct a thorough review of the National Ambient Air Quality Standards (NAAQS) for PM2.5 every five years to determine whether existing standards should be retained or revised. Following a complete review in 2020, the EPA retained the PM2.5 standard of 12 micrograms per cubic meter. However, under the Biden administration, the EPA reopened the review and changed the standard to 9 in a rule finalized in 2024.
In 2025, the EPA under the Trump administration reversed the federal government’s position in the litigation and asked the D.C. Circuit to vacate the rule, agreeing with NAM that the previous administration had used an unlawful regulatory shortcut.
“The D.C. Circuit allowed the rule to stand, relying on a legal argument the previous administration never invoked to defend its actions,” Kelly said. “An agency cannot simply disregard the substantive safeguards required by Congress to impose a sweeping new regulatory burden—and a court should not rescue an unlawful rule with an argument the government never raised.
“Manufacturers need the ability to obtain permits, expand operations, modernize facilities and invest in communities across the country. This standard puts those investments and the jobs they support at risk,” Kelly said.
