Numerical modeling of pollutant transport and chemistry during a high-ozone event in northern Taiwan

An air pollution prediction model system (APOPS) is developed and applied to northern Taiwanwith complex terrain and local thermal circulations. It consists of a nonhydrostatic mesoscalemeteoro-logical model system (MMPMS) and a gas/aerosol transport and air quality model(GATAM). The basic processes relevant to modeling the urban air pollution problems such asmeteorology, dispersion, chemistry and deposition are solved at the same time on practicallythe same grid. The APOPS was tested on a high-ozone event in northern Taiwan on 16 November 1998. Comparison with observed surface winds shows able to predict local flowpatterns such as sea/land breezes and mountain-valley wind in this high air pollution episode.The predicted surface concentrations of ozone and other pollutants are compared with measuredvalues, and a fairly good agreement with the mean normalized biases of ^-6%, ^-11%, for onedaysimulation and for daytime, respectively, is obtained for ozone. Thus, it is confirmed thatthe APOPS can be utilized to predict urban air quality in complex terrain area.