SAN DIEGO, CA — April 24, 2025 — In a sobering reminder of the public health challenges linked to environmental degradation, the American Lung Association (ALA) has released its annual State of the Air report, naming San Diego-Chula Vista-Carlsbad the eighth most smog-polluted metropolitan area in the United States. This alarming designation places San Diego County alongside four other California regions in the top 10 worst areas for ozone pollution, underscoring a statewide air quality emergency that continues to escalate.
According to the ALA’s 2025 report, nearly 155 million Americans—approximately half of the nation’s population—are breathing air that fails to meet federal health-based standards. These individuals live in counties that received failing grades for either smog (ozone) or particle pollution. Notably, San Diego County received an “F” grade for ozone pollution, citing a significant number of high ozone days, while earning a “B” grade for 24-hour and annual particle pollution levels.
“Air pollution is not just an environmental issue—it’s a public health crisis,” said Harold Wimmer, President and CEO of the American Lung Association. “The consequences are immediate and severe: children suffering asthma attacks, outdoor workers facing respiratory illness, and newborns at risk of low birth weights. Climate change, extreme heat, and more frequent wildfires are only making matters worse.”
Ground-Level Ozone: A Hidden but Deadly Threat
The report emphasizes the grave effects of ground-level ozone pollution, commonly known as smog, which is formed when pollutants from vehicles, industrial facilities, and other sources react under sunlight. Described as a “sunburn on the lungs”, inhaling smog can result in coughing, shortness of breath, and can exacerbate conditions such as asthma and chronic bronchitis. Prolonged exposure may even reduce life expectancy.
Warmer temperatures, driven by climate change, are intensifying the formation of smog, making cleanup efforts increasingly difficult. This poses significant challenges not only for regulators but also for families, schools, and employers striving to protect public health.
California Counties Dominating Pollution Rankings
In a trend that has now become alarmingly consistent, California continues to dominate the list of the most polluted regions in the country. The ALA report ranks Los Angeles-Long Beach as the worst metropolitan area for smog in the U.S., followed closely by Visalia (2nd), Bakersfield-Delano (3rd), and Fresno-Hanford-Corcoran (5th). These regions, like San Diego, have consistently grappled with unhealthy air, worsened by population growth, vehicular traffic, and climate-induced disasters such as wildfires.
San Bernardino County holds the undesirable title of the most ozone-polluted county in the nation, with neighboring counties such as Riverside, Los Angeles, Tulare, and Kern closely following. Furthermore, Kern County tops the chart for both short-term and year-round particle pollution, painting a dire picture for Central and Southern California.
The issue isn’t confined to urban centers. The report notes that rural and agricultural counties—like Kings, Madera, and Merced—are also experiencing high concentrations of pollutants, highlighting the statewide nature of the crisis.
The Call to Action: What Comes Next
The American Lung Association is using this report to advocate for stronger federal and state-level environmental policies. The organization is calling on elected leaders to invest in clean energy, enforce stricter emissions regulations, and support vulnerable communities disproportionately affected by pollution.
San Diego’s placement in the top ten is a wake-up call. As one of the nation’s leading coastal metropolises, San Diego has an opportunity—and a responsibility—to lead by example. Local authorities, businesses, and residents must work in concert to advance sustainable transportation, green infrastructure, and air quality monitoring systems that prioritize health and resilience.
The data presented in the State of the Air report not only raises urgent concerns but also fuels momentum for innovation, community action, and policy reform. With the world watching California’s climate strategies, the time for transformative change is now.
“This year’s findings are not just numbers in a report—they represent real lives affected by preventable air pollution,” Wimmer emphasized. “Our communities deserve clean air. Our children deserve a healthy future.”
About the American Lung Association
The American Lung Association is the nation’s leading organization working to save lives by improving lung health and preventing lung disease through education, advocacy, and research. With more than a century of service, the ALA remains at the forefront of environmental and public health issues that affect Americans every day.
For more information or to access the full report, visit: www.lung.org