Abstract:

Seasonal samples were collected in Baoshan and Xuhui areas. Fine particles were extracted with acidic extraction solution and strong acidity measured. Composition of water soluble ions was measured with ion chromatography. In situ acidity of fine particles was estimated with the thermodynamic aerosol inorganic model. The results show that fine particles were acidic in the urban area while sometimes alkaline in the suburb industrial area. Acidity of fine particles was significantly correlated with concentrations of mineral components such as calcium and magnesium. Anthropogenic fine particles would promote the formation of acid rain, increase of the relative concentration of fine particles in the total airborne particles could be an important reason for the increase of acid rain frequency in recent years.

Key words: fine particles; acidity; water soluble ions; acid rain