On August 28, the NAM joined a coalition of leading business groups in filing a petition for certiorari asking the U.S. Supreme Court to review and reverse the D.C. Circuit’s decision allowing the EPA’s unlawful and unworkable air quality standard for fine particulate matter, or PM2.5, to stand. In late June 2026, the D.C. Circuit issued its disappointing decision upholding the Biden EPA's 2024 lowering of the National Ambient Air Quality Standards for PM2.5 to 9 micrograms per cubic meter, an unacceptably low standard that will hamstring U.S. economic growth, job creation and competitiveness.
Our petition underscores the legal missteps of the D.C. Circuit’s reasoning. The lower court concluded that the EPA could revise the NAAQS outside the Clean Air Act’s five-year review cycle without completing a “thorough review.” The court found the authority for this novel off-cycle revision in a provision of the CAA that the Biden administration never invoked in its briefing before the court. The court’s reliance on that provision appears to violate the party presentation principle—the SCOTUS-backed notion that competent counsel, acting as advocates, are best suited to select, frame and argue the issues for decision on their clients’ behalf. Conversely, the courts, acting as neutral arbiters, normally decide only the issues presented by the parties.