San Bernardino County still ranks among worst for ozone pollution despite slight improvement

REDLANDS, Calif. — Air quality in San Bernardino County has improved slightly, but the region remains one of the most polluted in the nation, according to the American Lung Association’s 2026 State of the Air report.

Why it matters: Despite small gains, the county’s poor air quality still leaves hundreds of thousands of residents exposed to harmful pollution that can trigger asthma attacks, heart problems and long-term lung damage. Children, older adults and those with chronic conditions are among the most affected.

Details: The report, which analyzes data from 2022 to 2024, shows that San Bernardino County’s weighted average number of unhealthy ozone days dropped to 159.2, down from 177 days in the previous reporting period.

While that’s progress, the report remains troubling.

San Bernardino County received an F grade for ozone pollution, with 177 unhealthy for sensitive groups days, 151 unhealthy days and 37 very unhealthy days.

In other words, that amounts to roughly five months of unhealthy air each year.

Even with the improvement, the county still records 33 more unhealthy ozone days than Riverside County, the next closest region.

Health concerns: According to the American Lung Association, local estimates for San Bernardino County show that 37,488 children and 133,172 adults live with asthma. More than 61,000 residents have COPD and over 113,000 people have cardiovascular disease

Children are especially at risk. Nationally, the report found 46% of children—33.5 million—live in areas with failing air quality grades, and 7.3 million live in counties failing all three pollution measures.

For young people whose lungs are still developing, exposure to ozone and particle pollution is particularly dangerous. Health impacts can include reduced lung growth, increased asthma risk and long-term respiratory issues.

The report also found that people of color are more than twice as likely as white residents to live in areas failing all pollution measures with Hispanic individuals more than three times as likely.

Zoom out: Across the U.S., the report found that 152.3 million people—44% of the population—live in areas with unhealthy air pollution levels.

Ozone pollution in particular is worsening in many regions. Driven by extreme heat, wildfire smoke and other climate-related factors, more communities are experiencing spikes in smog.

Southern California remains a hotspot. The Los Angeles metro area – which includes San Bernardino and Riverside counties – once again ranked as the most ozone-polluted in the nation, position it has held in 26 of the report’s 27 years.

“Clean air is not something we can take for granted. It takes work,” Harold Wimmer, president and CEO of the American Lung Association said. “Now is the time to strengthen air pollution standards, but [Environmental Protection Agency] is doing the opposite. In the last year, EPA has weakened enforcement and rolled back rules that would have protected kids from power plant and vehicle pollution.”

Moving forward: While the latest data signals slow progress, San Bernardino County firmly remains in the nation’s worst tier for ozone pollution.

“Children need clean air to grow and play, and communities need clean air to thrive,” Wimmer said. “Leaders at every level must act to improve and protect America’s air quality.”