TWC offers three lists of polluted picks determined by three different variables: short term particle pollution, year round particle pollution, and ozone pollution.
Oh-no-zone: DFW Ranks 7th in Ozone Pollution
7. Washington, D.C. Heavy traffic saturation on I-395 and other major freeways is a high contributing factor to the ozone pollution in our nation's capital.
Updated at 10:30 AM CST on Friday, Jan 9, 2009