Ammonia

Tens of millions of Americans, including many Texans like me, live in counties that will soon be violating air pollution particle standards for the first time. It’s not that our air is getting dirtier – it’s because the U.S. Environmental Protection Agency just tightened its cap on the deadliest air pollutant: fine particulate matter, or PM2.5. The EPA acted because the Clean Air Act requires it to periodically review existing standards for six major air pollutants to ensure that the targets protect public health. Its 2022 scientific review showed that fine particles increase rates of illnesses and death even when inhaled at levels below existing standards. The EPA estimates that meeting its new standard would yield up to US$77 in health benefits for each $1 of control costs and would save up to 4,500 lives in 2032. Now, states must develop plans that meet the standard. As an atmospheric scientist who has studied air pollution for a quarter century, I’...