25th Annual “State of the Air” Report Highlights Long-Term Progress, Ongoing Pollution Challenges in California

Californians experience the worst air quality in the United States according to the American Lung Association’s 25th annual “State of the Air” report which was released today. The new report finds that despite decades of strong progress in cleaning the air, more than 9 out of 10 Californians live in a community earning a failing grade for unhealthy ozone pollution days, unhealthy particle pollution days and/or unhealthy annual particle pollution levels. More than 8 in 10 Californians live in an area with failing grades in each category.

"With a quarter-century of air pollution data behind it, “State of the Air” 2024 clearly shows that progress is being made but that much more work lies ahead when it comes to healthy air in California as our climate crisis intensifies,” said Mariela Ruacho, Senior Manager for Clean Air Advocacy with the American Lung Association in California. “California must aggressively tackle air and climate pollution by maintaining strong policies and budget priorities. This is not the time to slow or cut state investments supporting those living in communities that bear the greatest burden of unhealthy air.”

Twelve California cities appear on at least one of the lists of the 25 most polluted cities in the nation. Los Angeles-Long Beach, Bakersfield, Fresno-Madera-Hanford, Sacramento-Roseville, San Jose-San Francisco-Oakland, and Visalia appear on all three of the most polluted cities lists for unhealthy ozone days, particle pollution days and annual particle pollution levels. Notable California findings from the “State of the Air” 2024 report follow:

Southern California remains America’s most ozone-impacted region: For the 24th time, Los Angeles-Long Beach ranks as the most ozone-polluted (“smoggiest”) metro area in the United States. While the region has experienced significant improvements in all categories over the course of the report, San Bernardino County ranks as the most polluted with an annual average of 175 unhealthy ozone pollution days in “State of the Air” 2024. San Diego-Carlsbad ranks as the 8th most ozone-polluted city in the nation and is among the most polluted for short-term particles. El Centro ranks among the nation’s most polluted for both ozone and annual particles in this year’s report.

Progress and challenges in the San Joaquin Valley: The nation’s most particle-polluted communities are in the San Joaquin Valley. The report finds that Bakersfield is the most polluted city in America, in terms of unhealthy days of particle pollution and annual particle pollution levels. Bakersfield also ranks third in the nation for unhealthy ozone days and saw worsening on all three pollutant measures compared to the prior report. Bakersfield, Fresno and Visalia are the only cities in the nation to land among the five most polluted for all three measures included in “State of the Air.” Visalia saw its highest number of unhealthy particle days in the history of the report. Fresno improved to its best-ever report for ozone pollution having seen ozone days fall from 174 in the 2000 report to 52 ozone days annually in “State of the Air” 2024. San Joaquin County earned its first passing grade for ozone pollution days in this year’s report, marking the first passing grade for ozone in the region over the history of the report.

Wildfire impacts continue in many communities: In the three years covered by this report, individuals in the U.S. experienced the highest number of days when particle pollution reached “very unhealthy” and “hazardous” levels in the history of the “State of the Air,” including dozens of days in each range in California. Sacramento-Roseville appears among the Top 10 for each of the most polluted cities lists, with major wildfire smoke events pushing annual particle levels higher than in previous reports. Chico and Redding-Red Bluff also appear among the Top 10 most polluted cities for short-term spikes in particle pollution following wildfire events covered in this report. Wildfires also added to the burdens reported in the San Jose-San Francisco-Oakland metro area, where every county earned a failing grade for particle pollution days.

“California policies to speed the transition to zero-emission cars, trucks, rail operations and other sectors to protect health and reduce disparities are critical to meeting our pollution challenges,” said Will Barrett, Senior Director for Nationwide Clean Air Advocacy with the Lung Association. “California needs additional actions by EPA to support local clean up and for the agency to approve California’s clean air programs to bring the benefits of these programs to life without further delay.”

“State of the Air” grades exposure to unhealthy levels of ground-level ozone air pollution, annual particle pollution and short-term spikes in particle pollution over a three-year period. This year’s report includes air quality data from 2020-2022 and is updated to reflect the new annual particle pollution standard that the U.S. Environmental Protection Agency (EPA) finalized in February.

The “State of the Air” report found that nationally, more than 131 million people live in an area that received a failing grade for at least one measure of air pollution, and 43.9 million people live in areas with failing grades for all three measures.

Communities of color are disproportionately exposed to unhealthy air and are also more likely to be living with one or more chronic conditions that make them more vulnerable to air pollution, including asthma, diabetes and heart disease. The report found that a person of color in the U.S. is more than twice as likely as a white individual to live in a community with a failing grade on all three pollution measures.

Both ozone and particle pollution can cause premature death and other serious health effects such as asthma attacks, heart attacks, strokes, preterm births and impaired cognitive functioning later in life. Particle pollution can also cause lung cancer.

EPA recently finalized new air pollution rules that will help clean up particle pollution and address climate change. Now, the Lung Association is urging EPA to set long overdue stronger national limits on ozone pollution. Stronger limits would help people protect themselves and drive cleanup of polluting sources across the country. See the full report results and sign the petition at Lung.org/SOTA.