2007년 3월 서울 황사 사례의 PM_(10) 이온조성과 반응성 기체 특성

Abstract

Asian dust evens took place in Seoul on 27~28 March and 31 March~1 April 2007, during which the mass and chemical compositions of PM_(10)were measured at urban area in Seoul, Korea. In conjunction with PM_(10)compositions,the behaviors of gas precursors such as CO, O3, SO2, and NO2 and meteorological parameters and air mass trajectories were thoroughly examined. The earlier case was a weak dust incidence which was characterized by elevated concentrations of CO, SO2 and NO2 as well as secondary aerosols. In contrast, the later showed the trait of the dust aerosols associated with high PM10 mass and Ca2+ concentrations. In general, the fractions of ionic species against mass decreased with increase in dust loading. The ratios of SO42- to NO3- and SO2 to NO2 were similar in temporal variations, suggesting the concentrations of secondary aerosols were sensitive to the level of precursor gases. In this study, Na+ and Cl- were also highly elevated during the heavy dust episode, which is thought to have originated from alkaline soils spreading through the northeast regions of China.