Chemical Element Balances and Identification of Air Pollution Sources in Sakai, Osaka (II)

Abstract

Size distributions of total suspended particulate matter (TSP) and various elements were predicted by chemical element balance method and compare with observed ones. The size distribution of particles originating from main source components were estimated separately. The predicted size distribution of TSP agreed fairly well with the observed one in coarse particle region, but disagreed appreciably in fine particle region. The predicted and observed elemental size distributions agreed with each other in a wide range of particle size for non-volatile, lithophile elements, but disagreed appreciably for the elements, S, Cl, Cr, Co, Ni, As, Se, Cd, Sb, I and W. Possible explanations for these disagreements were given. The comparison of predicted and observed size distributions, in addition to the comparison of predicted and observed atmospheric concentrations, will be useful for deepening the understanding about the contributions of various aerosol source components and for testing the quality of the prediction. The following items are regarded to be important for improving the chemical element balance method attempted in the present study.(1) Appropriate elemental compositions of particles originating from iron-and-steel industry and diesel engine exhaust should be determined.(2) Accurate data on the secondary aerosol formation from SO₂, NO_x and hydrocarbons should be collected.(3) A new method to make better prediction for volatile elements should be developed, in which it is taken into consideration that they condense on particles upon cooling in ambient air after escaping from high temperature flues.