The list is based upon Toxic Release Inventory data from the Environmental Protection Agency (EPA), which documents reported emissions of mercury, hydrochloric acid and other hazardous metals.
Kentucky tops the list at No. 1, followed by Ohio, Pennsylvania, Indiana and West Virginia — residents of these states suffer from the pollution of surrounding coal-fired power plants.
The NRDC acknowledges that air quality is improving (a 19 percent drop in 2010, compared to 2009 levels) thanks to recent standards put into place by the EPA, but also warns that both Texas state senators supported a recent resolution to stop the mercury and air toxic safeguards.