Air pollution fouls Mount Rainier Park

A National Park Service employee changes an ozone sampler in Mount Rainier National Park

June 2, 1999
Web posted at: 11:20 AM EDT

Ozone from Seattle, Washington and other urban centers in the state is drifting into Mount Ranier National Park and affecting the air quality there, according to a recent U.S. Geological Survey study.

According to Dr. David Peterson of the USGS Forest and Rangeland Ecosystem Science Center, the air around Mount Ranier contains higher concentrations of ozone, a major component of air pollution, than nearby urban centers. The study provides more evidence that pollution from outside sources does affect protected areas such as natural parks.

The study was published in the scientific journal "Atmospheric Environment."

Peterson and his students monitored ozone at Mount Rainier National Park from 1993 to 1997 and quantified the spatial distribution of this pollutant throughout western Washington in 1996.

The park consistently had the highest average weekly levels of tropospheric ozone measured anywhere in the state. According to the scientists, ozone concentrations tend to increase at higher altitudes, partly because of passive dispersion from the stratosphere, but largely due to the transport of pollutants by prevailing winds inland from urban sources, such as the Seattle metropolitan area.

Ozone is a natural component of the Earth's atmosphere, but its effects vary depending on where and in what concentration it occurs. High above the Earth's surface, in the stratosphere, a protective layer of ozone screens the Earth from biologically harmful frequencies of ultraviolet radiation. The stratospheric ozone layer is essential to the existence of many forms of life.

However in the lower part of the atmosphere, called the troposphere, human-produced ozone can be a dangerous pollutant. The colorless gas is formed from byproducts released during the burning of fossil fuels, and can be toxic to both plants and animals, including humans, even at fairly low concentrations.

"It's well-documented that both periodic episodes of high ozone exposure and chronic moderate ozone exposure can be harmful to plants," said Peterson. "We know this from other regions of North America including national parks such as Sequoia and Great Smoky Mountains."

Ozone is usually caused by industrial pollutants and exhaust from automobiles. Emissions tend to be concentrated in urban areas, however the common assumption that ozone pollution is strictly an urban problem is proving to be false, Peterson said.

According to the study, a climber at Paradise, a common destination in the park that is 60 miles from Seattle, is subject to twice the monthly mean ozone concentration as Lake Sammamish, which is near sea level and less than 10 miles east of Seattle.

Mount Rainier National Park Resource Manager Barbara Samora said the ozone study "is just one more indication of how difficult it is to protect our national parks. It isn't a simple matter of telling people to stay on footpaths or to sensibly locate campgrounds and parking lots. How do you manage a threat that is produced 60 miles from the park and transported here by winds?"

"It is time to consider the potential for damage to park ecosystems and even potential health hazards to park visitors," Peterson said. "We've long known that parks cannot be managed as islands, separate from their surroundings. These findings about tropospheric ozone concentrations lend additional support to that position."

For more information, contact David Peterson, University of Washington, (206)543-1587, email: wild@u.washington.edu.

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