America's Dirtiest Cities

California's got seven of them. Will voters finally help clean the Golden State's brown air?

By Christopher Helman,

Nov 16, 2010 Provided by:
Forbes.com




Top 5 Dirtiest Cities in America

No. 1: Bakersfield, Calif.
Population: 800,000
Short-term particle pollution rank: 1
Year-round particle pollution rank: 2
Ozone pollution rank: 2
Hot, dusty and surrounded by California's San Joaquin Valley oil fields, Bakersfield has all the ingredients for the worst air in the nation

No. 2: Los Angeles-Long Beach-Riverside, Calif.
Population: 17.8 million
Short-term particle pollution rank: 4
Year-round particle pollution rank: 3
Ozone pollution rank: 1
University of Calgary researchers found in 2008 that salty coastal air mixed with sunshine and pollutants helps create unexpectedly high levels of ground-level ozone.

No. 3: Fresno-Madera, Calif.
Population: 1.1 million
Short-term particle pollution rank: 2
Year-round particle pollution rank: 6
Ozone pollution rank: 4
Cars, agriculture, petroleum and mega-dairies all contribute to the brown haze that hangs over the San Joaquin Valley.

No. 4: Visalia-Porterville, Calif.
Population: 430,000
Short-term particle pollution rank: 8
Year-round particle pollution rank: 3
Ozone pollution rank: 3
Proximity to the giant trees of Sequoia National Park isn't enough to clean Visalia's smoggy San Joaquin Valley air.

No. 5: Hanford-Corcoran, Calif.
Population: 150,000
Short-term particle pollution rank: 10
Year-round particle pollution rank: 8
Ozone pollution rank: 6
Hundreds of aircraft based at the giant Naval Air Station in nearby Lemoore doesn't help Hanford's air quality.