San Bernardino tops list of dirtiest U.S. cities, Los Angeles close behind

San Bernardino has claimed the top spot in a new report ranking the dirtiest cities in the United States, with Los Angeles following closely at number two.

The report, titled 2025's Dirtiest Cities in America by LawnStarter, evaluated cities based on several factors, including living conditions, infrastructure, pollution levels, and consumer satisfaction. Data was sourced from agencies such as the Centers for Disease Control and Prevention, the U.S. Census Bureau, and the U.S. Bureau of Labor Statistics.

Reactions to the rankings were mixed among locals interviewed by CBS Los Angeles. While one resident said he agreed with the findings, another argued Los Angeles should have taken the top spot instead.

"Research suggests nitrogen dioxide — a harmful pollutant — is around 20% more prevalent near warehouses," LawnStarter noted on its website. "12 cities in San Bernardino County collectively have over 850 large warehouses (100,000 sq ft or larger)."

Several other California cities also made the top 20, including Ontario (No. 4), Corona (No. 10), Santa Monica (No. 13), and Glendale (No. 15).