The association’s annual State of the Air Report was released Thursday, on the eve of Earth Day.
The association used U.S. Environmental Protection Agency data from 2018 to 2020 to formulate air quality "report cards" nationwide.
Cities in the West and Midwest continue to dominate the most ozone-polluted list. California remains top state with most cities on the list, with 11 of the 25 most-polluted cities.
Five California cities on the list plus the New York metro area recorded their fewest days of high ozone in the report’s 23-year history, although three of them are still among the ten most ozone-polluted cities in the nation
Cities that improved enough to be removed from the list were Milwaukee and Sheboygan, Wisconsin; Philadelphia; and the Washington-Baltimore metro area. They were replaced by San Luis Obispo, Reno, Detroit and San Antonio.
The geographical distribution of cities with the worst ozone problems continues a trend seen over the past six reports: fewer eastern cities and more western cities.
The best recommendations to cut down on emissions are ride your bike, take public transit, and go electric if you can, according to the association.
Tune in to FOX 11 Los Angeles for the latest Southern California news.