California
California’s bad reputation for poor air quality is highlighted by several cities with the worst air quality in the U.S. The cities of Los Angeles, Visalia, Bakersfield, and Fresno are among the
most polluted cities in the U.S. A large port industry, large population, significant traffic emissions, major agriculture industry, and growing wildfires all contribute to California’s challenges with poor air quality. In addition, areas of California with mountainous terrain create the scenario for pollution to be trapped. Warm climates and low rainfall contribute to growing and frequent wildfires.