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San Antonio made the list of the 25 most polluted cities in the nation in the American Lung Association's 2025 State of the Air report.
The Alamo City finished 20th on the ozone pollution list but was spared a mention on two other dubious lists for polluted cities — those with the most year-round particulate matter and those with the most short-term particulate matter.
The lists are based on the average number of days declared "unhealthy" by government environmental agencies, with the most such days earning cities the highest rankings.
Nick Torres, advocacy director with the American Lung Association, said the ozone pollution in the fast-growing Alamo City is getting worse by the year.
"It's been kind of an upward trend for the last six years or so," he said. "It was ranked 24th for us last year, so this year's ranking at 20th kind of shows things moving in the wrong direction."
Torres said ozone pollution is largely the result of vehicle emissions in the city and emissions from the outlying oil and gas industry. It is made worse when combined with sunshine. He said increasing heat waves across the country and locally are adding to the problem too.
Little or no breeze also allows ozone pollution to hover over an area, and it does not help that San Antonio lays south and southeast of the Hill Country. Those hills can help trap polluted air over the Alamo City.
Torres said high ozone pollution is bad for everyone's health, not just the young or old and those with health conditions like asthma and COPD.
"It's really an irritant for the lungs," he said. "A lot of people might call it sandpaper for the lungs and so really ... can cause respiratory stress in anyone."
Houston finished as 7th worst in the nation for ozone pollution, and Dallas-Fort Worth was listed as 10th worst. The top three worst cities in the nation for ozone pollution are all in California — San Bernadino, Riverside, and Los Angeles.
The Texas Commission on Environmental Quality issued Ozone Action Days for San Antonio because of high ozone pollution. On those days, residents are asked to help prevent ozone pollution by carpooling and putting off vehicle refueling and lawn mowing with a gas-powered mower until after 6 p.m.
Other tips include turning off vehicle engines in drive through lanes and avoiding other engine idling where possible.
