Is the air quality bad in California? Report finds harmful pollutants plague these areas
Is the air quality bad in California? Report finds harmful pollutants plague these areas
Air pollution impacts some Americans more than others. Here’s why.
Four out of 10 Americans breathe polluted air every day, and some are bearing that burden more than others. Here’s why.
- Worsening ozone levels can be attributed to smoke from wildfires in Canada in 2023 and higher temperatures combined with emissions in the South.
- The American Lung Association found that 156.1 million Americans are living in places that received failing grades for its ozone or particle pollution, a figure up from last year’s report.
- The Bakersfield-Delano metro is the worst in the nation when it comes to particle pollution.
The Los Angeles metro is once again the worst for ozone in the nation, a harmful pollutant and “main ingredient in smog” that experts say millions more Americans were exposed to nationwide in a new report.
The American Lung Association released its State of the Air report for 2025, examining the levels of air pollution across the United States based on data compiled by the U.S. Environmental Protection Agency for 2021-2023, the most recent period of nationwide, publicly available data. The report looks at two of the “most widespread and dangerous” air pollutants: fine particles and ozone.
Ozone pollution isn’t just a California problem, as nearly 25 million more people across the nation, based on last year’s figure, have been exposed to ozone levels that put their health at risk. More than 125 million people live in counties with F grades for ozone pollution, the lowest grade possible and reflective of a poor score that involves the Air Quality Index.
“The severity of the problem and the abruptness of the change are unprecedented in magnitude,” the report said. “Nationwide, nearly five times as many counties’ ozone levels worsened as improved.”
The smoke spreading from wildfires in Canada in 2023 and high temperatures combined with emissions in the South are large factors of the worsening ozone, according to the report.
What are fine particles and ozone?
Fine particles refer to the size of particle pollution or particulate matter, a term for the mixture of solid particles and liquid droplets in the air that poses health threats, according to the EPA and the American Lung Association. Fine particles are “most often a by-product of burning wood or fossil fuels, and may include components such as toxic compounds, salts and metals,” said the American Lung Association.
The “main ingredient in smog,” ozone — or more specifically, ground-level ozone as opposed to the ozone naturally occuring higher in our atmosphere that protects us — is created by a chemical reaction involving sunlight and pollutants emitted by cars, power plants, refineries and other sources, according to the EPA.
Among the health effects between the two pollutants include aggravating asthma, damage to the airways and decreased lung function, irregular heartbeat and premature death in people with heart or lung disease, said the EPA.
The American Lung Association’s report found that 156.1 million Americans are living in places that receive failing grades for its ozone or particle pollution, which is up nearly 25 million more people compared to last year’s report. Extreme heat, drought and wildfires are worsening air pollution levels in the nation, the report said.
What are the worst areas in California for ozone pollution?
Nine California metro areas were ranked in the American Lung Association’s 25 worst cities for ozone. Here’s which:
- Los Angeles-Long Beach: No. 1
- Visalia: No. 2
- Bakersfield-Delano: No. 3
- Fresno-Hanford-Corcoran: No. 5
- San Diego-Chula Vista-Carlsbad: No. 8
- Sacramento-Roseville: No. 11
- San Jose-San Francisco-Oakland: No. 14
- El Centro: No. 17
- Redding-Red Bluff: No. 24
See the worst California metros for year-round particle pollution
The American Lung Association also released the worst 25 cities nationwide pertaining to year-round particle pollution. Here are the places in California that made the list.
- Bakersfield-Delano: No. 1
- Visalia: No. 2
- Fresno-Hanford-Corcoran: No. 3
- Los Angeles-Long Beach: No. 5
- San Jose-San Francisco-Oakland: No. 6
- Sacramento-Roseville: No. 14
- El Centro: No. 23
See the worst California metros for short-term particle pollution
The American Lung Association also released the worst 25 cities nationwide pertaining to short-term particle pollution. Here are the places in California that made the list.
- Bakersfield-Delano: No. 1
- Visalia: No. 3
- Fresno-Hanford-Corcoran: No. 5
- Reno-Carson City-Gardnerville Ranchos (both Nevada and California): No. 6
- Los Angeles-Long Beach: No. 7
- Sacramento-Roseville: No. 10
- San Jose-San Francisco-Oakland: No. 11
- Redding-Red Blugg: No. 16
Paris Barraza is a trending reporter covering California news at The Desert Sun. Reach her at pbarraza@gannett.com.