The U.S. is a melting pot — of ozone, particle and short-term pollution.

Every day, humans create a dangerous mix of harmful contaminants that are slowly but surely destroying our environment.

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The American Lung Association produces a State of the Air report each year, which details the U.S. cities with the worst air pollution. Major states like California and Texas largely dominate the list, thanks to their size, with repeat offender cities such as Los Angeles, Houston and Dallas. In fact, the top three cities of 2013 stayed in the exact same spots.

Here are the top 10 U.S. cities with the worst air pollution in 2014.