Report names U.S. cities with foulest, cleanest air

Report names U.S. cities with foulest, cleanest air
http://www.nlm.nih.gov/medlineplus/news/fullstory_111475.html

"The nation's 25 most smoggy cities improved air quality over the last year, but half the nation's residents still live with unhealthy levels of air pollution, according to an American Lung Association report released on Wednesday."