California is typically considered one of the most scenic states in the U.S., but it is also the nation’s leader in cities with the most polluted air.
That according to the just released 2026 “State of the Air” survey by the American Lung Association. It evaluates metropolitan areas based on three key metrics: Ozone pollution, short-term particle pollution (24-hour spikes), and annual particle pollution.
Five California cities dominated the top ten list of “year-round particle pollution” as well as ranking high in ozone production and short-term particle pollution.
A total of eight of the Golden State’s cities also ranked in the top 25 most-polluted cities in the nation.
Bakersfield and the surrounding Delano area has remained the most polluted in terms of “year-round particle pollution,” out of 211 American metropolitan areas, according to the report.
Four other California metro areas were found in the top ten for year-round particle pollution: Fresno-Hanford-Corcoran at number 4, San Diego-Chula Vista-Carlsbad and Visalia tied at number 5, and Los Angeles-Long Beach at number 7.
Other California cities on the year-round particle pollution list include the Bay Area cities of San Francisco, Oakland, and San Jose in a tie at number 13, with El Centro rounding out the list at number 21.
In terms of short-term particle pollution, Bakersfield improved from first on the list last year to third, with Fairbanks, Alaska, taking the number one spot.
Los Angeles again ranked first out of 226 metropolitan areas in ozone production, a dubious title it has held in 26 of the 27 years of reporting.
According to the report:
Ground-level ozone, sometimes known as smog, is one of the most widespread and dangerous pollutants in the United States. Scientists have studied the effects of ozone on human health for decades. Hundreds of studies have confirmed that ozone harms people at levels currently found in many parts of the United States.
Years of scientific research have clearly established that particle pollution and ozone are a threat to human health at every stage of life, increasing the risk of premature birth, causing or worsening lung and heart disease, and shortening lives. Some groups of people are more at risk of illness and death than others, because they are more likely to be exposed, are more vulnerable to health harms, or often both.
The report also concluded that “44% of Americans — 152.3 million people — are living in places that get failing grades for unhealthy levels of ozone or particle pollution.”
Those findings also noted that nearly half of American children, some 46 percent or 33.5 million people under 18, are living in places where at least one of the three metrics has a failing grade.
Additionally, 10%, or 7.3 million are living in places where all three metrics have failing grades.
Contributor Lowell Cauffiel is the best-selling author of the Los Angeles crime novel Below the Line and nine other crime novels and nonfiction titles. See lowellcauffiel.com for more.