Suddenly she had a strange vision, a billion coal-fired cooking stoves staining the sky with as bad a smog as a billion SUVs.

What you're seeing is the worst smog in America.

The American Lung Association's 2013 survey ranks the metro area as having the nation's worst smog, and fourth in both short term and year round pollution amounts.

Southern California companies face a daunting new challenge: proving they can figure out on their own how best to clean up the nation's worst smog.

Acadia recorded worse smog than Boston and Philadelphia.

Mr. Gore said that Houston was overtaking Los Angeles as the city with the worst smog in America.

Under the Clean Air Act, urban areas with the worst smog must sell only cleaner-burning fuel, at least during certain times of the year.

Scientists blame the emissions from automobiles, most of which still burn leaded gasoline, for the worst smog.

California, which has the worst smog in the nation, is moving ahead with far broader regulation of emissions from consumer products, including nail polish and lighter fluid.

Acadia has recorded worse smog than Boston or Philadelphia.