Based on the research works conducted in 2003 we report the following major findings. 1.Four Asian dust events were observed in north Taiwan in the spring of 2003. 2.Noticeable levels of particulate pollutants were found in the long-range transported air parcels. This suggested that long-range transport of air pollutants that originated in east China is one of the key factors affecting the air quality in north Taiwan in the season of prevailing northeasters. 3.The PM10 concentration over Taiwan in summer is lower that that in springtime. The major constituents of PM10 include sulfate, nitrate, ammonium, and carbon. The composition suggests that the particulate pollutants are mostly contributed by local pollution. 4.Daytime sulfate concentration in aerosols strongly correlates with ozone in Tainan, indicating the contribution of photochemical or secondary sources to the aerosol burden should be important in southern Taiwan. 5.According to the simulation of ozone episodes, strong northeasters can be induced by a typhoon, as it passing through the west Pacific Ocean. As a result, more ozone can be transported from the mid-latitudes to southern Taiwan. In addition, the secondary circulation of typhoon can cause extremely clear skies over Taiwan. Photochemical reactions can be enhanced by the strong UV radiation and result in drastic increases of ozone levels. 6.Based on the intensive measurement of VOCs during two ozone episodes in autumn of 2003, ethene, xylene, toluene, isoprene and propene are major precursors of ozone in the Kaohsiung-Pingtung area. 7.The ratios of specific VOCs vs. 22DMC4 are proposed as a useful tool for apportionment of the VOC between traffic and non-traffic sources. The results of this work show that the non-traffic contributions to ethane, toluene, and propene are 52%, 33%, and 41%, respectively, implying the importance of non-traffic emission of the ozone precursors to the formation of ozone in Kaohsiung-Pingtung area.

Atmospheric aerosols,Ozone,Asian dust,Air quality model