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Scientists Search Great Smoky Mountains For Ozone Damage

BOONE–Pointing to purple leaves, yellow needles and brown stems, Howard Neufeld easily spots ozone-damaged plants. Since the late 1980s the Appalachian State University biology professor has researched ozone in the Great Smoky Mountains National Park in hopes of gathering data to give regulators and policy makers the ammunition to tighten ozone laws.

With more than nine million visitors a year, the Smokies is the nation’s most popular park despite being one of the worst parks for air pollution. Sulfur pollution causes much of the park’s haze, shrinking hundred-mile views to one mile. Acid rain damages plant life and changes the qualities of the soil. But ozone remains the park’s

most harmful air pollutant since 1992 when levels in the park doubled in one year.

“This park is a crown jewel of the national parks, and if it is losing what is there to protect, then this is a huge loss for everyone,” Neufeld said. “We’ve identified 85 plants in the park that are being damaged by the ozone.

“This is a little like a ‘canary in a bird cage.’ If these plants are dying because of ozone, it could be a predictor of a greater change for all of us.”

Sponsored by a grant from the National Geographic Society, Neufeld and two colleagues are collecting more data on ozone-damaged plants in the Smokies.

“Some trees like pine and hemlock are resistant to ozone, but others like milkweed and black cherry are sensitive,” Neufeld said. “We’ll find two of the same plants beside each other and one is dying from ozone and the other is not. Even on the same plant we’ll find some healthy leaves beside dying ozone-damaged leaves.”

By cataloging and comparing ozone-damaged plants to healthy plants the research team hopes to unravel many of the mysteries of how ozone affects plant life.

Ozone results when nitrogen oxides and hydrocarbons react in sunlight. For humans ozone can make breathing difficult, especially for people with respiratory problems. For plants, ozone can bring premature death.

“Does ozone reduce growth, or slow reproduction or make the plant more susceptible to insect damage?” asked Neufeld. “There are so many questions and with the doubling of ozone levels we don’t have as much time to find the answers.”

Air stagnation in the Smokies occurs frequently, trapping and concentrating pollution. The park’s ozone, nitrogen and sulfur levels are among the nation’s highest. Much of the pollution blows in from distant sources including Chicago, Detroit, Indianapolis, St. Louis and on occasion New Orleans or New York City.

“We’re not sure why, but ozone levels increased dramatically starting in 1992,” Neufeld said. “We didn’t suddenly have more pollution. Instead I think what happened is a combination of conditions that were more favorable to the creation of ozone.

“We had eight of the 10 hottest years on record during the last decade and that

meant lots of hot and dry days that are perfect for ozone.”

Neufeld said that before 1992 ozone levels didn’t reach the unhealthy level of 120 parts per billion. Since 1992, levels of 120 ppb have become routine in the park.

“If plants were being affected in 1992 by ozone, image how the plants are being affected now,” he said. “We expect to see much more ozone damage during this research trip.”

Joined by Alan Davison, professor of agricultural and environmental science at the University of Newcastle, England, and Art Chappelka of Auburn University, Neufeld will study plant-life along the North Carolina and Tennessee border of the park.

“Our hope is to understand why a plant is responding in a certain way to ozone,” Neufeld said. “There is not much you can do for wild plants, but you could breed ozone resistant plants and crops.

“For the ecologist, the benefit is understanding and being able to predict the impact of ozone. Right now we can’t predict what the park will look like 50 or 100 years from now, but with the proper data we can.”

Other studies have shown ozone causes $2 billion a year in damage to commercial crops.

“Crops get a lot of study and so do trees,” Neufeld said. “Wildflowers don’t get a lot of attention so we are focusing on those plants.”

Neufeld will continue the research next year by creating flower gardens at different altitudes within the park.

“Ozone shows different patterns according to the time of day and the altitude,” Neufeld said. “At elevations below 4,000 feet, ozone levels begin low, build during the day and peak mid-afternoon before returning to low levels at night.

“The problem at elevations above 4,000 feet is that the ozone levels never return to low levels. Often the levels peak at night. So the plants above 4,000 feet receive constant levels of ozone and are damaged more.”

Much of the Smokies is above 4,000 feet, so that is one contributing factor to the park’s high ozone levels. The flower gardens should give the researchers more information on the role of altitude and ozone levels.