The American Lung Association’s State of the Air 2025 report reveals a troubling reality: 156 million people, nearly half of people in the U.S., live in counties that had unhealthy levels of ozone or particle pollution. This national report analyzes data from official air quality monitors and compiles the results about two of the most widespread and dangerous air pollutants, fine particles and ozone.
Inside the State of the Air report, find grades and rankings for the cleanest and most polluted places to live by searching by zip code or state. In California specifically, counties in the state represent some of the most polluted cities when it comes to ozone, year-round particle pollution and short-term particle pollution also some of the cleanest US cities.
For more information and to view the report, click here.