Following are some of the results of our completed or ongoing projects:
Emissions and ozone production
TVA, in partnership with the Southern Oxidant Study (SOS), has conducted field research on the chemistry of ozone formation in plumes from large nitrogen oxide (NOx) point sources and urban sources of NOx. Aircraft data collected during the 1995 Nashville/Middle Tennessee Ozone Study suggest that urban NOx produces ozone 65 to 70 percent more efficiently than power plant NOx.
Fine particulate matter in the Great Smoky Mountains
Airborne fine particles (PM2.5) have been linked to adverse health effects and regional haze. PM2.5 measurements indicate that the Tennessee Valley will have difficulty meeting the recently revised, stringent National Ambient Air Quality Standard for Particulate Matter. A collaborative research effort supported by TVA, the Department of Energy, the Electric Power Research Institute, and the National Park Service is monitoring PM2.5 mass and chemical composition in the Great Smoky Mountains National Park. Analysis of the data has revealed the relative abundance of sulfate and organic carbon aerosols as the primary components of PM2.5. The correlations between aerosols, ambient gaseous pollutants, and meteorological factors are being examined to learn more about the origin and evolution of the particulate matter.
Particulate matter standards
On Earth Day 1997, TVA and state and local air quality organizations from the Tennessee Valley initiated a regional, urban-oriented, eight-station fine particle (PM2.5) monitoring network. Three years and over 1,500 samples later, data indicate that seven of the eight stations would likely exceed the annual PM2.5 standard.
Sulfate production in plumes from a scrubbed coal-fired power plant
Comparisons of plumes from TVAs Cumberland Fossil Plant before and after installation of the flue-gas desulfurization process indicate that the lower sulfur dioxide emissions have led to reductions in particle sulfate and a corresponding improvement in visibility within the plume. Sulfate production rates, inferred from airborne measurements, were nearly identical to those measured before scrubber installation.
Atmospheric modeling for SAMI
TVA, working with the Georgia Institute of Technology, has performed air pollution modeling for the Southern Appalachian Mountains Initiative (SAMI). The modeling has examined the formation of ozone, aerosols, and acid deposition across southern Appalachia with emphasis on pollutant exposure in ecologically sensitive places, such as national parks and wilderness areas. Future emission scenarios were modeled to determine the potential for future environmental impacts. View detailed results here.
Plume models of ozone formation
TVA, with the Electric Power Research Institute, the Southern Oxidant Study, and the University of Alabama in Huntsville, has developed and tested a new model for simulating the photochemistry of plumes from large point sources. This model simulates the detailed chemistry that occurs in plumes, including the delayed formation of ozone that occurs just downwind from the point of emission. Advanced models like these are needed for improved modeling to support regulatory decision-making.
Other environmental resources and services