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Ozone reaches unhealthy levels in Smoky Mountains National Park |
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Great Smoky Mountains National Park reached maximum levels of unhealthy ozone pollution Friday (June 9) and continued to measure unhealthy levels at its high elevation sites through Wednesday, posing a threat to the health of park visitors.
Park managers emphasized that this advisory is specifically for higher elevation areas while ozone levels at lower elevations outside the park may be lower. Maximum 8-hour ozone averages over the weekend reached as high as 110 ppb (Cove Mountain) and 112 ppb (Clingmans Dome) at two of the Park's five air quality monitoring stations. Clingmans Dome also exceeded the 1-hour ozone standard for the first time ever with a 1-hour average concentration of 128 ppb on June 10. The other three air quality monitoring stations also exceeded the 8-hour standard but stayed between 85-105 ppb. Under federal and state standards in Tennessee and North Carolina, an 8-hour average ozone concentration of 85 ppb or greater is unhealthy. The exceedance June 11 marked the 10th time this year that unhealthy levels have been reached. In 1999, which was the worst year in the Park's history, the 10th exceedance day did not occur until July 23. Natural ozone levels are estimated to be 20-40 ppb. The U.S. Environmental Protection Agency has identified several groups of people who are at risk from ozone exposure: those with respiratory problems such as emphysema, asthma, and chronic bronchitis; individuals engaging in heavy outdoor exercise either recreationally or at work as well as children at play; and a few otherwise healthy individuals who are especially sensitive to ozone and suffer greater loss of lung function than the general population. These visitors may wish to refrain from strenuous outdoor activities while this condition is in effect. Ozone, considered a secondary air pollutant, is formed from primary emissions of nitrogen oxides (from coal-fired power plants, motor vehicles and factories) and volatile organic compounds in the presence of sunlight. Ozone pollution is a powerful respiratory irritant in some people, causing shortness of breath, coughing, wheezing, scratchy eyes, nose, and throat, and chest pain while breathing deeply. Visitors experiencing these symptoms are advised to reduce strenuous outdoor activity and take shelter indoors. Ozone pollution also is causing visible leaf injury to 30 species of vegetation at the park such as black cherry, yellow poplar, and tall milkweed. Typically, ozone levels in the higher elevations of the Smokies remain at dangerously high levels for a more extended period of each day than occurs in low elevations where the levels generally spike in late afternoon then drop rapidly in the evening. The Park is now presenting air quality monitoring data to the public through a new computerized display located at Sugarlands Visitor Center and on its World Wide Web Site. The data includes information on current visibility measurements, ozone pollution concentrations levels, weather conditions, and real time digital camera pictures taken from the Look Rock Air Quality Monitoring Station. |
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