The air was thick and gray, and
all along the Foothills Parkway, nobody was pulling into
the scenic overlooks, simply because there wasn't much
to see.
Rich Mountain, next to Cades Cove, should have been
clearly visible some 15 miles to the southeast, but not
on this day. With temperatures hovering above 90 degrees
and no wind to scatter the stagnant air, the Smoky
Mountains scenery was obscured by a blanket of
photochemical smog.
"Over the years, the average visibility at this park
has been reduced to about 25 miles," said Scott Berenyi,
air-quality technician for the Great Smoky Mountains
National Park. "Today it's about half that."
This year, for the fourth consecutive year, the
National Parks Conservation Association placed the Great
Smoky Mountains National Park on its list of 10 most
endangered parks because of ongoing damages from air
pollution.
With air pollution recognized as the Smokies' No. 1
resource threat, it's perhaps no surprise that the park
maintains the most extensive air-quality monitoring
program of any national park in the country.
There are seven monitoring stations in all, scattered
throughout the park's 800 square miles. They range in
elevation from 1,850 to over 6,000 feet, and while data
is collected year-round, summer is when the monitoring
goes into full swing.
Some of the sites measure particulate matter to
determine visibility, while others record acid
deposition, mercury levels, as well as a broad spectrum
of weather data.
Ground-level ozone - a colorless gas that damages
plants and acts like sunburn on human lung tissue - is
measured at five stations throughout the park. So far
this year, the park has issued eight ozone advisories,
the most recent occurring on Monday and Tuesday. Park
officials say that so far this summer, the Smokies have
had about the same number of unhealthy ozone days as
last year.
The park's air-quality monitoring program was
initiated in the early 1980s and is a joint project
between the National Park Service, the Tennessee Valley
Authority, the Environmental Protection Agency and the
state of Tennessee.
Jim Renfro, air-resource specialist for the Smokies,
said the long-term data allows researchers to determine
how provisions of the Clean Air Act are affecting
protected natural areas like the park.
"The Smokies ought to have some of the cleanest air
in the country, but unfortunately, when you add up haze,
acid deposition and ozone, there're not many national
parks that get hit with the air pollution we have," he
said.
Renfro said that over the past 10 to 12 years, ozone
levels in the park have gone up, both in terms of
seasonal averages and the number of unhealthy ozone
days. He said that visibility also has deteriorated over
the last decade despite federal programs aimed at
reducing haze.
The park's main pollutant obscuring visibility is
sulfur dioxide, which converts into acid droplets and
particles, causing haze and acid rain. Researchers say
that approximately 77 percent of the sulfur dioxide
emissions that affect the Southern Appalachians come
from coal-fired power plants.
Nitrogen oxide - emitted mostly from automobiles and
coal-fired power plants - is a key ingredient of the
ozone pollution that plagues the park during the summer.
In addition to its long-term sulfur dioxide and
nitrogen oxide monitoring, the park and TVA this year
have installed mercury monitoring equipment at two sites
located at elevations ranging from 2,100 to over 6,000
feet.
Mercury comes mostly from coal-fired power-plant
emissions and, like nitrogen oxide and sulfur dioxide,
can be transported far from its original source by wind.
Humans are exposed to mercury primarily by eating fish.
Renfro said that at this point, the park is the only
place doing mercury monitoring in Tennessee.
He said a key feature of the park's air-quality
monitoring system is that meteorological data such as
wind speed and direction, solar radiation and barometric
pressure is collected at all the sites.
"The weather parameters tell us what conditions lead
up to good air or bad air," Renfro said. "Today we have
lots of sunlight, which increases the chemical reaction
that forms pollution and allows the pollution to build
up.
"There's not much wind, which allows the pollution to
build up, and the higher humidity allows sulfur
particles to grow even more haze. And we also get lots
of rain, which deposits pollutants in the soil.
"Weather plays such a large role in air quality, and
a host of weather-related natural factors predispose
this park to air pollution threats."
Renfro said that concomitant to the air-quality
monitoring stations tracking pollution in the park,
scientists and universities are discovering how that
pollution damages the park's resources.
Projects range from the effects of acid deposition on
the park's soils and streams to how ozone is damaging at
least 30 plant species in addition to threatening human
health.
"Great Smoky Mountains National Park is a regional
canary in a coal mine," Renfro said. "Most of our
air-quality issues are transport-related, but the
research is showing that Tennessee sources have the most
impact on our air pollution, followed by the Southeast
region in general.
"If things get worse here, there're getting worse
throughout the region. And if we start solving the air
problems in the Smokies, we've solving them across the
Southeast, too."
Morgan Simmons may be reached at 865-342-6321 or
simmonsm@knews.com.
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