Nearly half of Americans are now living in areas with unhealthy levels of air pollution, according to the American Lung Association’s 2025 “State of the Air” report.
The study found that about 156 million people, 46% of the U.S. population, are exposed to dangerous levels of ozone or particle pollution. That’s an increase of 25 million from last year. Researchers say climate change, driven by extreme heat, wildfires, and drought, is worsening air quality.
In Tucson, ozone is the biggest concern, especially from April through September, according to Pima County. Pollution that forms ozone comes from cars, power plants, industry, and even some vegetation.
Officials recommend paying attention to local air quality alerts and limiting outdoor activity on high-ozone days to reduce health risks.
