The 20 Dirtiest Cities in the U.S.

California has 7 of the 20 cities with the poorest air quality, according to a list complied by Forbes. Bakersfield, which has 60 days of unhealthy air a year, takes the top spot for its hot and dusty weather and proximity to oil fields.

On the state level, California regulations on carbon emissions such as a cap-and-trade programs, and reducing vehicle emissions should help improve the air quality in its cities.

Further improvements will be made at the federal level as well. The Environmental Protection Agency's expected rules on power plants will lead to companies either retrofitting plants with new technology, or closing power plants altogether, reports Christopher Helman.

Data from The American Lung Association's State of the Air 2011 report was used to compile this list.

Full Story: America's 20 Dirtiest Cities


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