Pollution

April 29, 2009 -- Areas in California remain some of the most polluted in the U.S., with air quality that is likely damaging the health of millions of people, according to a report by the American Lung Association. Almost 186.1 million Americans live in places where the air quality is probably bad enough to damage their health, at least part of the year, the report concludes. The Pittsburgh-New Castle area in Pennsylvania ranked the worst in the nation for short-term particle pollution and second for the most year-round particle pollution. Particulates come from a variety of sources, including diesel and gasoline engines, power plants, construction and demolition projects, soil, and dust.