Chemical composition and component analysis of atmospheric wet deposition in Chiang Mai province

Abstract

This study examined the chemical composition and sources of atmospheric wet deposition collected for 16 months from September 2006 to December 2007 at Mea Hia Research Center, Chiang Mai University, Chiang Mai Province. Total precipitation was 1219.0 mm. Mean Electro conductivity and pH values were 0.62 mS/m and 5.93, respectively. The relative volume weight mean concentrations eq/L of anions in a descending order were SO4 2- (11.94) > NO3 - (8.13) > Cl- (5.31) > CH3 COO- (3.72) > HCOO- (2.61) > PO4 3- (0.32) and those of cations were NH4 + (17.29) > Ca2+ (12.89) > Mg2+ (5.77) > Na+ (3.63) >H+ (1.17) > K+ (1.93). The dominant ions for cations and anions are NH4 + and SO4 2- , respectively. Results of a component analysis highlighted the influence of various sources, such as combustion fuel, agricultural activity, photochemical processes, soil resuspension and marine source on the chemical composition of the rainwater collected at this study site.