Seeing the park land through the haze.

Parks and wilderness areas in the United States may look clean, but widespread air pollution across the country drastically diminishes visibility in even some of the most remote parklands, according to "Protecting Visibility in National Parks and Wilderness Areas," a National Research Council report. Current efforts aimed at improving visibility, however, will not solve the problem and in some cases are "doomed to failure," say the researchers who drafted the report. In the western United States, people can see only half to two-thirds of the 230-kilometer range that would be possible without pollution. In the east, average visibility is only one-fifth the natural range of 150 kilometers. The vista-diminishing pollution comes from coal-burning power plants, diesel- and gasoline-fueled vehicles, residential and forest fires, and even livestock farms. Sources spread out over hundreds of kilometers contribute to the pollution, which also harms human health.

Congress in 1977 set a goal of reducing haze in large national parks and wilderness areas, but the Environmental Protection Agency, the Agriculture Department, and the Interior Department have been slow to carry out their responsibilities for reaching that goal, the report says. In particular, it faults current efforts to improve visibility by targeting just individual polluters, a tactic the National Park Service used in a recent case involving a coal-burning power plant near Grand Canyon National Park. The report calls instead for strategies that consider the various sources in a region that contribute to haze.