WASHINGTON - A 10-year government study of air quality at major national parks found foliage-killing ozone levels rising at 20 of the 32 parks surveyed, including Yellowstone, Shenandoah, the Great Smoky Mountains and the Everglades.
About half of 29 parks surveyed for acid rain were found to have continuing or worsening problems from nitrate deposits. Sulfate concentrations associated with acid rain were on the rise in five parks, with Indiana Dunes National Lakeshore reporting a slight decrease.
The National Park Service study came last week as the National Parks Conservation Association, a citizen watchdog group, released a report citing Virginia's Shenandoah, the Great Smoky Mountains in North Carolina and Tennessee, Kentucky's Mammoth Cave, Sequoia and Kings Canyon in California, and Maine's Acadia as the five most polluted parks in the United States.
"In the Great Smoky Mountains, our most polluted national park, ozone pollution exceeds that of Atlanta, Ga., and even rivals Los Angeles'," said Harvard Ayers, chairman of the Appalachian Voices conservation group. The Great Smoky Mountains National Park encompasses 800 square miles of mostly forested mountains and has a particular diversity of plants and animals.
In a statement bearing the title "Ten-Year Study Shows Improvement in Air Quality in National Parks," Park Service Director Fran Mainella emphasized the positive aspects of the survey.
"The report shows that in most parks, air quality exceeds standards set by the Environmental Protection Agency to protect public health and welfare," Mainella said. "Our findings also show that some parks occasionally experience pristine air quality conditions, unaffected by air pollution."
She noted that of 28 parks monitored for visibility, "22 had improving visibility conditions on the clearest days."
However, the report also showed that, measured on the worst days for haziness, 10 of the parks experienced worsening visibility. Acadia National Park on the Maine seacoast has twice the haze problem of the Grand Canyon.
While pointing to Alaska's Denali National Park and Nevada's Great Basin National Park for high visibility, Mainella conceded that Mammoth Cave, Shenandoah and the Great Smoky Mountains had the worst visibility of the surveyed parks and that serious problems were also found at Big Bend in Texas and Colorado's Mesa Verde National Park near the Four Corners region.
According to the Park Service report, "ground-level ozone is one of the most widespread pollutants affecting vegetation and public health throughout the world, and is caused by the reaction of nitrogen oxides and volatile organic compounds in the presence of sunlight."
The National Parks Conservation Association report found that the Smoky Mountains park had violated federal health standards more than 175 times since 1998 and suffered damage to 30 species of plants.
The conservation group's study also found that ozone levels exceeded human health standards on 61 summer days last year at Great Smoky Mountains, while rainfall at Mammoth Cave is 10 times more acidic than normal.
The group blamed the pollution on coal-fired power facilities, aging industrial plants and motor vehicle emissions. It called on the Bush administration to enforce rather than eliminate Clean Air Act provisions, and for the government to reduce vehicle emissions by requiring greater fuel efficiency.