El Paso and Los Angeles ranked among the most polluted U.S. cities in 2025, according to IQAir’s annual global air quality report.
Nationwide, average air pollution rose 3% from 2024 to 2025, reaching 7.3 micrograms of fine particulate matter per cubic meter-well above the World Health Organization’s recommended limit of 5.
In Texas, El Paso saw pollution surge by 46% due to historic spring dust storms, while other major cities like Houston and Austin recorded declines. East Los Angeles, along with neighboring Huntington Park and Cudahy, formed the nation’s worst air quality zone, driven by devastating California wildfires.
Western cities dominated North America’s pollution rankings, though San Francisco and Seattle met WHO guidelines. Chicago, New York, and Washington, D.C. also saw worsening air quality.
The report identified three key drivers: climate-fueled wildfires-including Canada’s second-worst fire season on record-industrial emissions, and a new source: artificial intelligence data centers. These facilities indirectly increased pollution through soaring electricity demand and directly via diesel backup generators.