Calif. Farm Town Is Nation's Smoggiest

Marco Lopez jogs along train tracks Tuesday, Aug. 7, 2007 in Arvin, Calif. Arvin is home to the nation's worst air pollution. Arvin's level of ozone, the primary component in smog, exceeded the national limit by an average of 73 days per year between 2004 and 2006. Second on the EPA's list was the Southern California town of Crestline, at 65 days. The San Francisco Bay Area averaged just four days over the same period. (AP Photo/Gary Kazanjian)