Abstract: ICP-AES,ICP-MS and IC were used to analyze the chemical composition of fine and coarse fractions of atmospheric aerosol samples collected in Changdao,Shandong Province from March 28 to April 8,2002,in order to investigate the concentration variation of aerosol constituents and sulfate formation route during the Asian Dust event from April 6 to 8,2002.The Asian Dust event could be divided into the front part and the sequential part.The mineral dusts of the front part intereacted extensively with a variety of pollutants,and featured by the elevated sulfur content;while mineral dusts of the sequential part preserved their inherent chemical compositional characteristics during long-range transport process.Ammonium sulfates were found the major compounds mainly in fine mode aerosol.It implies that heterogeneous phase oxidation as the major route for sulfate formation,rather than the neutralization between basic components of mineral dusts and acidic pollutants in air.This formation process was dominated by fine particles.Ammonium sulfates might be converted into other sulfates such as koktaite and gypsum during atmospheric transport.During transportation course of the Asian Dust,conversion of sulfur-containing pollutants goes on not only from gases to particulate,but also from fine to coarse particles.