Report: Most Americans in areas with unhealthy air

(AP) -- Sixty percent of Americans live in areas with unhealthy air pollution levels, despite a growing green movement and more stringent laws aimed at improving air quality, the American Lung Association said in a report ...

Dirty snow causes early runoff in Cascades, Rockies

Soot from pollution causes winter snowpacks to warm, shrink and warm some more. This continuous cycle sends snowmelt streaming down mountains as much as a month early, a new study finds. How pollution affects a mountain range's ...

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