Model correlations for ozone, reactive nitrogen, and peroxides for Nashville in comparison with measurements: Implications for O-3-NOx-hydrocarbon chemistry

摘要

We present an analysis of correlations between O-3, NOx reaction products (NOz), and peroxides in photochemical models for polluted environments in comparison with measurements in the vicinity of Nashville, Tennessee. This analysis is associated with the use of O-3/NOz, H2O2/NOz, and similar ratios as indicators for the relative impact of NOx and hydrocarbons (volatile organic compounds, VOC) on ozone formation. The measurements are used both to evaluate the NOx-VOC indicator theory and to identify NOx-VOC chemistry in Nashville. Results show that a linear correlation exists between O-3 and the sum 2H(2)O(2)+NOz, consistent between models and measurements. The ratio O-3/2H(2)O(2)+NOz has a near-constant value in both the Nashville urban plume and surrounding rural area. A similar correlation is found with total peroxides (O-3 versus 2peroxides+NOz) but with greater scatter. The correlations between O-3, NOz, and peroxides are consistent with an assumed dry deposition rate of 5 rm s(-1) for H2O2 and HNO3. Changes in dry deposition and RO2 reaction rates cause minor adjustments in the NOx- VOC-indicator analysis for H2O2/NOz. Measured indicator ratios for Nashville are close to the NOx-VOC transition predicted by models and form an intermediate point between previous measurements for Atlanta (NOx sensitive) and Los Angeles (VOC sensitive). The model ozone production efficiency (P(O-3)/L(NOx)) is 3-4, significantly lower than would be derived from the O-3-NOz slope (5-8). [References: 52]