Modeling atmospheric PM 10 concentrations during severe pollution events in southern Taiwan

Abstract

This work simulates the hourly variations of PM 10 (suspended particles with diameter < 10 μm) during severe pollution events in southern Taiwan (Kaohsiung City and Pingtung County) in spring, autumn and winter of 2005 by using the Air Pollution Model (TAPM). Comparisons between simulations and measurements at three sites (industrial, urban and rural) were satisfactory. The synoptic weather chart indicated that prevailing winds were northwest (spring), north (autumn), and northeasterly (winter). Meteorological conditions suggest that PM 10 typically accumulated and triggered a pollution episode on days with high surface pressure and low winds. Estimations using the TAPM model suggest that point-source emissions were the predominant contributors (about 49.1%) to PM 10 concentrations at Hsiung-Kong industrial site in Kaohsiung City, followed by area sources (approximately 35.0%) and neighboring transport (7.8%). Because Pingtung City (urban) and Chao-Chou town (rural) are located downwind of Kaohsiung City when north or northeasterly winds prevail, the two sites also experience severe pollution events despite the lack of industrial sources; neighboring transport contributed roughly 39.1% to PM 10 concentrations at Pingtung and 48.7% at Chao-Chou. Since traffic emissions contributed little (around 8%) to PM 10 concentrations at the three sites, reducing PM 10 emissions from industrial sources in Kaohsiung City should be an effective way of improving air quality for Kaohsiung City and downwind areas such as Pingtung County.