Bakersfield, CA
- High ozone days per year: 99
- No. of days with unhealthy particle pollution: 26
- People with asthma: 65,700
- Population: 893,119
At the south end of Central Valley, Bakersfield had the highest number of extreme particle pollution days out of all the most polluted cities in the United States. Emissions from the area’s agriculture sector and oil refineries, in addition to freight and automobile traffic, lead to nearly 100 days of high ozone in a year, the fifth highest number of average days of high ozone a year.