A regional air quality model: Evaluation and simulation of O3 and relevant gaseous species in East Asia during spring 2001

A regional air quality model (RAQM) has been introduced, evaluated and applied to investigate the behaviors of tropospheric O3 and relevant species in East Asia. Model simulation is performed with an up-to-date monthly emission inventory [Streets, D.G., Bond, T.C., Carmichael, G.R., Fernandes, S.D., Fu, Q., He, D., Klimont, Z., Nelson, S.M., Tsai, N.Y., Wang, M.Q., Woo, J.-H. and Yarber, K.F., 2003. An inventory of gaseous and primary emissions in Asia in the year 2000. Journal of Geophysical Research 108 (D21), 8809. doi:10.1029/2002JD003093] for March 2001 when extensive experimental data sets were available, including ground-level observations and the TRACE-P (TRAnsport and Chemical Evolution over the Pacific) aircraft experiments, which allow a comprehensive evaluation for this model system. Model validation demonstrates that RAQM is able to represent most of the major processes of chemical species in the troposphere, with model results agreeing with observations reasonably well. Statistical analysis has been conducted for both meteorological parameters (wind speed, temperature and humidity) and chemical components (10 key gaseous species) by comparing with the TRACE-P data sets. At altitudes <5 km, the correlations (R) for meteorological parameters are all above 0.8, with temperature the highest (0.97). The model produces the highest R for O3 (around 0.75), followed by CO (0.66–0.72) and HO2 (0.7), and the lowest R for NOx (0.1–0.2), with R = 0.4–0.7 for the remaining species. The model successfully reproduces the major features in chemical transport associated with the Asian outflow and reasonably explains the observed fluctuation in species concentrations at downwind monitoring sites over the western Pacific.