New York Times: The country’s treasured open spaces are no more immune to air pollution from coal-fired power plants than are its big cities. Sulfur dioxide causes acid rain and kills trees. Mercury emissions poison streams. Nitrogen oxides and sulfates create smog and haze. For all these reasons, Congress in 1977 amended the Clean Air Act to require the Environmental Protection Agency to make a special effort to clean the air in national parks, wildlife refuges and other places of "scenic" and …