Dear Mr. Zients, The undersigned state and regional associations representing sectors and industries across the U.S. economy urge you to maintain the existing National Ambient Air Quality Standards for particulate matter (PM2.5). A proposed revision to this standard is under review by the White House Office of Information and Regulatory Affairs. This proposal could put nearly 40% of the U.S. population in areas of nonattainment,¹ risking jobs and livelihoods across the nation and making it significantly more difficult to obtain permits to build new factories, bridges, and roads that will power our economic growth. Implementation of the Infrastructure Investment and Jobs Act, the CHIPS and Science Act, and the Inflation Reduction Act have the potential to infuse substantial investments into our states and communities, but all of that is now threatened by the permitting restrictions that would flow from this proposal. This regulation will put nearly every goal to encourage manufacturing in our states and regions at risk and could prevent the American economy from reaching its full potential.

Our members have innovated and worked with regulators to lower PM2.5 emissions significantly. The Environmental Protection Agency’s 2022 Air Trends and National Emissions Inventory report shows that PM2.5 concentrations have declined by 42% since 2000,² driven by major emissions reductions from both mobile sources and the power sector. As a result, our air is cleaner than at any point in modern times. The current PM2.5 standard is set at 12 μg/m³; yet, some are advocating a standard as low as 8 μg/m³—which is lower than naturally occurring levels in many parts of the country. This proposal is also far more stringent than the guidelines in place in Europe, where the current EU standard is 25 μg/m³ more than twice the current level in the U.S.