Long-range transport of Asian dust and air pollutants to Taiwan: observed evidence and model simulation

Abstract

Abstract. Long-range transport of Asian dust and air pollutants are major environmental concerns of Taiwan during the winter monsoon season when northeasterly winds prevail following passages of cold fronts. Based on hourly measurements of Taiwan Environmental Protection Administration (TEPA) air quality monitoring stations, Lidar and in-situ IC, a significant long-range transport dust and air pollutants event on 18 March 2005 has been identified. During this episode, drastically elevated concentrations of PM10, CO and SO2 along with the strong northeasterly on 18 March were observed over background Wanli station, with peaks of about 170 μgm−3, 1.0 ppm and 14 ppb, respectively. We have found that air masses of air pollutants and Asian dust are transported separately. Although the mixing takes place on the way to Taiwan, it mixes slightly when they arrived in Taiwan. The major component of the first PM10 peak were air pollutants, evidenced by the consistent peaks of SO42− and NO3