O3 AND NOY RELATIONSHIPS AT A RURAL SITE

Measurements of O3, NO, NO2, peroxyacetyl nitrate (PAN), HNO3, and NO( y) were made during a 6-week period in the summer of 1991 in Giles Cou nty, Tennessee. These data were analyzed to determine the factors cont rolling the relationship between O3 and NO(y) at this rural site. A st rong association was observed between the O3 and NO(x) oxidation produ ct (NO(z) = NO(y) - NO(x)) levels. The higher O3 levels were associate d with air masses impacted by higher NO(x) emissions that had been pho tochemically processed. An analysis of the data indicates that the ult imate O3 production is about 10 molecules Of O3 produced for each mole cule of NO(x) emitted. The analysis results also suggest that O3 net p roduction continues until about 70% of the NO(x) has been converted in to NO(z). The PAN/HNO3 ratios observed suggest that the air masses in Giles County are composed of higher volatile organic carbon/NO(x) rati os than the air masses observed at other rural sites in eastern North America. A comparison of the data analysis results to model simulation s and smog chamber experiments suggests that most of the time, Giles C ounty is in an NO(x)-limited regime for O3 production.