SCIENCE / MEDICINE : Vaninshing Vistas : Those Post Card Views Are Often Smog-Shrouded : Environment: Pollution mars America’s national parks more than 90% of the time.
Millions of families this summer will flee smog-bound cities for the majestic surroundings of America’s national parks, only to find that air pollution has beat them there and clouded the post card vistas.
Unfortunately, air pollution in the parks is neither isolated nor new. According to National Park Service statistics, man-made pollution affects the scenic park views more than 90% of the time.
“You don’t know how important a clear view is until you travel a long way to see the parks and then find bad air,” said Mark Scruggs, chief of research for the National Park Service Air Quality Division in Denver.
According to Scruggs, pollution problems in certain parts of the country have improved in recent years, but the atmosphere at other parks has become much worse.
Because of the extreme variability in weather conditions, the Park Service has not been able to identify a national trend concerning the air quality in parks. But there are notable changes in specific regions. The air quality at western parks (based on selected sites) has improved in recent years, according to data from the Park Service and other sources, while it has continued to deteriorate in eastern parks.
In general, the parks with the best visibility are in eastern Nevada, western Utah and southern Idaho. The next-best air is in the Colorado plateau region, which includes the Grand Canyon, Bryce Canyon and Zion National parks, followed by northern Arizona, most of New Mexico and the Colorado Rockies.
The worst visibility is found in the Shenandoah (Virginia) and Great Smoky Mountains (Tennessee/North Carolina) parks.
In the West, the poorest visibility is along the coasts of California and Washington.
Although a portion of the visibility problem--which is seen in various forms of haze conditions--can be attributed to causes such as traffic dust, it is primarily caused by sulfate particles produced by utilities and heavy industry.
These particles, emitted by smelters, power plants, refineries and oil and gas fields, can travel long distances in the atmosphere. In the Colorado Plateau region, sulfate particles cause 40% to 60% of the pollution, and in Eastern parks these particles are an even greater contributor to haze and smog.
But pollutants from faraway urban areas can also be significant causes of park air pollution. For example, Southern California industry makes a substantial contribution to the pollution of the Rocky Mountain and Grand Canyon national parks, while much of the Shenandoah park pollution can be traced to the industrial centers of Detroit and Gary, Ind.
The impact of these and other sources varies from summer to winter. In the summer, unstable weather conditions help carry sulfate pollutants from urban industrial areas to remote parks such as Rocky Mountain and Grand Canyon, creating seasonally worse haze conditions. During winter months, locally produced pollution can be trapped for several days by stagnant air masses.
The Park Service has observed some improvements in some western regions. For example, according to a Park Service report, the visibility of the Colorado Plateau Region has improved since pollution peaked there in 1985. The reason for the improved visibility in these parks appears to be a reduction in the sulfur oxide emissions from nearby copper smelters. Since 1982, four smelters have been closed and another three have installed advanced pollution-control technology.
Meanwhile, in the East, park pollution has become steadily worse over the last 40 years. According to the Park Service, sulfate levels in parks such as the Great Smoky and Shenandoah are 10 times greater than western parks. The problem, Scruggs said, is that the number of sulfate-spewing polluters has increased.
Other studies underscore the Park Service conclusion. For instance, the National Weather Service has shown that the average summertime visibility over much of the eastern United States has decreased more than 50% since 1948 to a current visual range of less than 15.5 miles.
Scruggs said that a few more years of data will be needed to conclude that visibility is declining or remaining the same on a national basis throughout the park system. But he leaves little doubt that air pollution is a major problem.
“Everywhere we monitor we have found visibility impairment due to man-made conditions,” Scruggs said. “When the visibility is bad you can’t see the colors, textures or shadows, (and) to me that’s a serious issue.”
Park Service scientists also worry about the long-term effects of air pollution on the park system’s flora and fauna. Research has indicated that certain air pollutants can cause reduced growth and higher mortality in sensitive plant species. Animals are also affected as their food sources become contaminated or depleted. Scientists are also concerned that the buildup of acid deposits from sulfur oxide emissions may be harmful to plant and animal life, but a direct link between the two has not yet been made.
Air pollution also has a dramatic effect on park visitors. The Park Service has conducted surveys that show that most visitors would travel farther and pay higher entrance fees to ensure better visibility during their park stay.
The surveys also pointed out that even a small increase in air pollution is more apparent and disturbing to park visitors who are counting on enjoying spectacular views.
“Of course, visitors from more urban areas may come (to a polluted park) and think it’s a great view,” Scruggs added.
As part of its responsibility to protect air quality, the Park Service has expanded an air-quality research and monitoring network established in 1978.
The 1977 Clean Air Act Amendments provided the impetus, setting a goal of improving existing air quality and eliminating future visibility problems in the nation’s parks.
Monitoring consists of a variety of techniques, including the use of 35mm cameras which record changes in visibility during different weather conditions.
Other devices measure airborne particulates and air clarity. Currently, 55 U.S. parks are being monitored, mostly in the West, where open panoramas and generally cleaner air allow for long-distance viewing.
Although the Park Service has no authority to control pollution sources outside the parks, it does influence the Environmental Protection Agency and other government bodies. Armed with the data collected from its monitoring program, the Park Service evaluates conditions, compiles reports and makes recommendations.
One of its most important activities is to review permit applications for industrial and energy-generating facilities near the parks. Since 1978, the Park Service has reviewed nearly 300 applications to ensure that existing and planned sites do not harm air quality.
Although no permit applications have been denied, some have come quite close, including a pulp mill in Maine. Moreover, the Park Service has recommended modified emission-control technology in several instances. A notable example of the review process focuses on the Navajo Generating Station near the Grand Canyon.
Based on previous monitoring, the Park Service has determined what portion of the Grand Canyon pollution it believes can be attributed to this facility. The EPA is now assessing that information and early next year will reach a decision on how best to control the emissions.
Still, no matter how much monitoring, evaluating and reporting, it is clear that the national parks’ once-pristine views may never be the same. As Scruggs emphasized, visitors will never have the opportunity to enjoy the views that turn-of-the-century travelers once took for granted.
“It’s frustrating to . . . know the visibility could be better,” he said. “People think they can go to the parks and escape from the problems faced in urban areas, but it’s no longer possible.”
SOURCES OF SULFATE AT GRAND CANYON SOUTHERN CALIFORNIA: 33% ARIZONA SMELTERS: 15% MOJAVE: 14%
NAVAJO: 7% ELY, NEVADA: 6% NEW MEXICO REFINERIES: 5% SALT LAKE CITY: 5% SAN FRANCISCO: 4% MEXICO: 3% ALBUQUEQUE: 2% EL PASO: 2% NEW MEXICO SMELTER: 2% FOUR CORNERS: 1% COLORADO: 1%
Source: National Park Service, Air Quality Division
