6 California Cities Among 10 Most Polluted in 2023: Report

Oil derricks at the Chevron Oil Field in Bakersfield, Calif., on Nov. 21, 2016. (Frederic J. Brown/AFP/Getty Images)

California cities make up the majority of the nation’s 10 most polluted places, according to a recent report by the American Lung Association.

The association’s 2023 State of the Air report (pdf), published in April, lists several of the state’s cities among the top 10 for most polluted in three categories.

Los Angeles remains the city with the nation’s worst ozone—or smog—pollution. The city has held the title for all but one of the 24 years tracked by the association.

Cars drive on a congested freeway in Los Angeles on Aug. 28, 2018. (Frederic J. Brown/AFP/Getty Images)

Meanwhile, Chico improved its air quality enough to move off the list of most smog-polluted cities.

Ten Golden State counties—Fresno, Kern, Kings, Los Angeles, Madera, Riverside, San Bernardino, Stanislaus, Sutter, and Tulare—received failing grades for all types of pollution

The five California cities most polluted by daily particulate matter, such as dust, dirt, or smoke, are:

• Bakersfield (also No. 1 nationally)
• Fresno-Madera-Hanford (No. 2 nationally)
• Visalia (No. 4 nationally)
• San Jose-San Francisco-Oakland (No. 6 nationally)
• Redding-Red Bluff (No. 7 nationally)

The five California cities most polluted by annual particulate matter are:

• Bakersfield (No. 1 nationally)
• Visalia (No. 2 nationally)
• Fresno-Madera-Hanford (No. 3 nationally)
• Los Angeles-Long Beach (No. 4 nationally)
• Sacramento-Roseville (No. 6 nationally)

The six California cities most polluted by ozone are:

• Los Angeles-Long Beach (No. 1 nationally)
• Visalia (No. 2 nationally)
• Bakersfield (No. 3 nationally)
• Fresno-Madera-Hanford (No. 4 nationally)
• Sacramento-Roseville (No. 7 nationally)
• San Diego-Chula Vista-Carlsbad (No. 8 nationally)

Nationally, seven cities were ranked as the cleanest cities for particle pollution and ozone. The cleanest cities are:

• Asheville-Marion-Brevard, North Carolina
• Bangor, Maine
• Greenville-Kingston-Washington, North Carolina
• Lincoln-Beatrice, Nebraska
• Rochester-Batavia-Seneca Falls, New York
• Urban Honolulu, Hawaii
• Wilmington, North Carolina