The American Lung Association’s 27th Annual State of the Air report reveals that 46% of the children in America (or 33.5 million people under the age of 18), and more than 4 in 10 people of all ages (152 million people), live in counties that received a failing grade for at least one measure of ozone pollution or particle pollution. This data, even though showing progress from previous years, highlights that we still have a long way to go to make sure millions of Americans have clean air.
This national report analyzes data from official air quality monitors and compiles the results of two of the most widespread and dangerous air pollutants, fine particles and ozone. Explore grades and rankings for the cleanest and most polluted places to live by searching by zip code or state.
In California specifically, the 2026 report ranks its cities among the most polluted in the United States. More than 8 in 10 Californians live in counties impacted by air pollution from transportation, industrial processes, power plants, and other sources. Climate change is making the job of cleaning the air more difficult as record heat and catastrophic fires add to the pollution challenges.
Learn more about how the state of California ranks on this State of the Air 2026 Fact Sheet for CA.