TRACE GAS CONCENTRATIONS AND EMISSIONS IN DOWNTOWN NASHVILLE DURING THE 1995 SOUTHERN OXIDANTS STUDY NASHVILLE INTENSIVE

Continuous measurements of O-3, CO, NOy, and SO2 and twice a day sampl es of hydrocarbons were made over a 40 day period in June and July 199 5 at the downtown Nashville Southern Oxidants Study (SOS) site located on the rooftop of the polk office building, 106 m above ground level, in the urban center. This site experiences elevated concentrations of VOCs, CO, and NOy, due to local emissions from the Nashville urban ar ea. High O-3 concentrations were also observed and are discussed with reference to violations of the existing air quality standard and the m uch harder task of meeting the proposed 8 hour average standard. A com parison between the VOC measurements made from the Department of Energ y G-1 aircraft with those measured downtown indicates a preferential l oss of reactive ingredients in the samples taken outside of the city. The concentration ratios, VOC/CO (ppbC/ppb), VOC/NOx (ppbC/ppb), and C O/NOx (ppb/ppb) were calculated to be 0.32, 2.9, and 9.3, respectively , from morning samples. These ratios agree to within 35% with estimate s from Nashville emissions.