Number of days with unhealthy air pollution in the U.S. 2022, by select city
In 2022, there were 93 unhealthy days for ozone and fine particle pollution in Los Angeles. This was slightly lower than the 10-year average of 110 days. By comparison, there were only five days in nearby San Francisco that reached unhealthy for sensitive groups or above on the Air Quality Index (AQI) for ozone and PM2.5 in 2022. In 2022, there were 597 days with unhealthy air pollution in the U.S..
Fine particle pollution can be produced from a number of sources, including emissions from cars, trucks, power plants, and factories, wildfires, as well as from chemical reactions of other air pollutants. Some of these factors also influence ozone, in addition to weather conditions.