Riverside County Once Again Among Most Polluted in the Nation

Riverside County is once again near the bottom of the country for air quality, and the surrounding region isn't doing much better.

The American Lung Association's State of the Air 2026 report ranks Riverside second worst in the nation for ozone pollution, trailing only neighboring San Bernardino County, which claimed the top spot. Riverside also lands in the top ten for both daily and annual particle pollution, coming in tenth on both lists. The county received failing grades across all three major pollution categories, placing it among just 20 counties nationwide to fail every measure.

Riverside isn't alone in the region. San Bernardino, Kern, Fresno, Kings, and Imperial counties also failed all three measures, making California home to nine of the twenty worst-performing counties in the entire nation. From city to city, Los Angeles ranked third in the country for ozone pollution, and San Diego placed ninth.

Health experts warn that this level of pollution raises the risk of asthma, heart disease, and other serious conditions, with children, older adults, and people with existing health issues facing the greatest danger.

The full report is available at Lung.org.