The LA basin and the San Joaquin Valley regularly experience unhealthy smog
This chart shows the average number of days per year that each monitoring station exceeded a federal health standard for ozone, the main ingredient of smog, from 2021-2023. In some areas of the Inland Empire, residents were breathing unhealthy air on average every three or four days.
A map of air monitoring sites in the South Coast and San Joaquin Valley air basins shows the average number of days per year that each monitoring station exceeded the federal ozone standard from 2021-2023. Some monitoring stations in the San Bernardino area exceeded the ozone standard an average of 100 days a year.
