INFLUENCE OF ASIAN DUSTS ON THE PHYSICOCHEMICAL PROPERTIES OF ATMOSPHERIC AEROSOLS IN TAIWAN DISTRICT——USING THE PENGHU ISLANDS AS AN EXAMPLE

Using the Penghu Islands as an example, this study investigates the influence of Asian dusts on the physicochemical properties of atmospheric aerosols in Taiwan District in the year of 2002. An aerosol-sampling site was established at Xiaumen, the Penghu Islands, to collect sea level atmospheric aerosols for further analysis of their phys-icochemical properties. This study revealed that, during the sampling campaign, three Asian dust storms were trans-ported from North China and Mongolia to the Penghu Islands. The mass concentrations of atmospheric aerosols, par-ticularly PM2.5~10, were generally 2~3 times higher than the regular level. An increase of coarse particle mode in the size distribution of atmospheric aerosols further validated the invasion of Asian dusts. Moreover, the comparison of wa-ter-soluble ionic species, carbonaceous content, and metallic content of atmospheric aerosols indicated that Asian dusts could significantly influence the chemical properties of atmospheric aerosols in Taiwan District. A significant increase of Cl-, Br-, Na+, K+, SO42-, Mg2+ and Ca2+ concentration on coarse particle mode was observed. It suggested that not just natural soil dusts and oceanic spray, but also anthropogenic pollutants could accompany Asian dusts. Source appor-tionment of atmospheric aerosols indicated that the concentration (percentage) of aerosol particles contributed from soil dusts increased significantly from 20.98 mg.m-3 (29.2%) to 60.37 mg.m-3 (47.7%), and then decreased to the regular level of 22.44 mg.m-3 (28.2%).