These are the 8 major US cities with the worst air pollution - and 4 are in California
- A recent report tracked air pollution levels in cities and countries around the world for 2018.
- While the United States performs well compared to the worst offenders like India and China, a few US cities still suffer from poor air quality.
- Major cities in California saw especially high pollution levels in 2018 due to wildfires, while a few industrial cities experienced dirty air from automobiles and power plants.
In the wake of the Camp Fire in Paradise, California, the state's northern areas saw pollution levels that surpassed those in China and India - two of the most polluted nations in the world.Read more: What air pollution does to your body and brain
Despite these dips in air quality, a recent report from IQAir, a global air quality database, found that average pollution levels in the US met the World Health Organization's standards for healthy air in 2018. But a few individual cities struggled to hit the same target.
The report listed dozens of US cities with "moderate" air quality, which could cause respiratory problems for sensitive individuals (e.g. children, older adults, or people with lung or heart disease) performing outdoor activities. Other cities showed pollution levels that fell just short of the WHO threshold.
Since these cities were often located in the same metropolitan area, we distilled the report's data to include only large metros (those with at least one million residents).
Take a look at the eight metropolitan areas with the worst levels of air pollution in the US.