The East is steadily losing its struggle to maintain postcard-perfect views of favorite remote summer vacation spots while the West is winning, according to a 10-year analysis of air quality in 12 U.S. national parks by University of California, Davis, researchers. The unexpected findings by physicists Robert Eldred and Thomas Cahill were published in the most recent issue of the international journal Atmospheric Environment. "On many days in the summer, visitors have no view at all except a strange, gray fog from many of the most popular lookouts," said Cahill, head of the UC Davis Air Quality Group. "But it's not fog. It's mostly sulfate particles, with lots of water attached. At times in the East, it is almost pure dilute sulfuric acid." Based on more than 12,000 measurements of the most remote -- and presumably the most pristine -- areas of the country from 1982-92, the UC Davis report questions basic assumptions about how sulfur emissions cause acid haze or acid rain, as well as the present regulatory solutions for the problem. The study also may have implications for global climate change. The immediate bad news for folks planning to get away to the great outdoors soon is that the air quality in most of the eastern parks declines sharply during the summer months. Despite sulfur emissions holding roughly constant in the decade 1982-1992, summer sulfate hazes in Great Smoky Mountains National Park, Tenn., soared almost 40 percent, making it the clear loser of the decade. Air quality in Shenandoah National Park, Va., was almost as bad. The sulfate hazes spread across a region as large as one-third of the country, the researchers report, meaning that summer days in eastern national parks share the same hazy air as cities such as Washington, D.C. Possible explanations include changes in the height of smokestacks, the chemistry of sulfur emissions, the location of sulfur sources and the weather. Meanwhile, views in the west are improving or holding steady, according to the UC Davis report. The most improved air quality in the study was Chiricahua National Monument, Ariz. The one-third reduction in sulfates there is probably due to surrounding copper smelters that shut down or adopted emissions controls during the decade, the researchers speculate. Other "winners" in national park air quality were Mesa Verde, Colo., and Canyonlands, Utah. Improvements in sulfate counts there may have been due to major reductions in sulfur dioxide emissions in the mid-1980s at neighboring coal-fired power plants, but these trends have yet to be connected with specific sources. "People who are concerned about long-term trends in air quality and the overall effectiveness of the sulfur controls mandated by the Clean Air Act should see this as an important paper," says Marc Pitchford, an atmospheric researcher with the Environmental Protection Agency's air research group and chair of the Interagency Monitoring of Protected Visual Environments (IMPROVE) program steering committee. "This is the first time anybody has had enough systematic data for remote areas to investigate the trends over 10 years," he said. Minute particles of sulfate are the main culprit robbing the eastern scenic areas of their stunning views. Almost all sulfate originates as sulfur dioxide emissions from coal-burning power plants and other industrial sources. After escaping from smokestacks, invisible sulfur dioxide molecules can transform into much larger, view-busting sulfate molecules, especially in humid regions. Sulfate also is the main ingredient in acid rain. "The surprising thing is that people were expecting the sulfate numbers to go down as more controls are put on power-plant emissions, and the fact is they haven't," Eldred said. He manages the UC Davis particulate-monitoring program, which identifies the chemical constituents of atmospheric aerosols at about 70 national parks and wilderness areas for U.S. land-management agencies. Most of the twice-weekly sampling and subsequent analysis is funded by IMPROVE, which is based on an earlier National Park Service program. The air over public lands has special visibility protection. When it revised the Clean Air Act in 1990, Congress mandated sulfur-dioxide emission controls, believing the visibility problem, as well as the acid rain problem, would decline in proportion to the reduced emissions. The UC Davis study suggests it may not be that simple. "The bottom line is that the Clean Air Act may not accomplish all that it was supposed to do, which is to clean up the air of the eastern United States," Cahill said. Scientists need to figure out why the air is getting worse, he said. This paper shows the importance of the network and should be used to justify further research into the causes of and solutions for sulfate haze, said Mark Scruggs, chief of the research branch of the National Park Service air-quality division. "For the first time, we can ask, are things getting better or worse. In the East, things don't look so good. In the Southwest, we can link some improvements to known emission reductions." Some of those improvements in sulfate hazes in the Southwest can be traced to earlier studies by the UC Davis Air Quality Group on copper smelters. In another recent study that may help boost the Southwest's clean-air trend, the researchers identified the power plant responsible for some winter haze episodes in the Grand Canyon. "The West only has a small number of large sulfur sources, so it's easier to find the smoking gun," Cahill said. "The East has hundreds of sulfur sources; it's just a soup. Only when everybody starts reducing emissions in the East will we see improvement, and even then it may not be as dramatic as the West." In another finding, the UC Davis researchers found five times less lead in the air at the end of the decade in all 12 national parks. "The lead levels have plummeted in response to the control of lead in gasoline across the country and to smelter controls in the West," Cahill said. The data come from a fine-particle monitoring network based at the UC Davis Crocker Nuclear Laboratory. Funded by a small grant from the Environmental Protection Agency, the UC Davis network began with three sites in Utah in 1977. Recently, the UC Davis program has grown into an ad-hoc international network involving 17 countries, yielding valuable new information for global climate research. The UC Davis group's archive of air samples now numbers close to 100,000. Last year, techniques and protocols developed by the UC Davis team were adopted by the United Nations' new Global Atmospheric Watch program.