Problems of soot pollution and environmental effects in northern china

Abstract

This paper presents results from a study of soot pollution problems in the Beijing-Tianjin area of China in 1983-1984. Soot is one of the main air pollutants in northern China. The average particular carbon concentration in the air is about 30 μg m−3 and the source is mainly coal combustion. Based on these experiments, using the moving parcel method, we estimate the conversion rate for oxidation of SO2 to sulfate to be in the range 2.2%-5.7% h−1. Contributions of the different components of the aerosol to visibility reduction have been calculated. The apparent sulfate and soot contributions to the visibility decrease are 52%-58% and 22%-29%, respectively. Results of a laboratory study indicate that transition metal ions and soot can be important catalysts for the oxidation of S(IV) in aqueous solution. Under ultraviolet light, transition metal catalysis is faster, while absence of such light favors catalysis by soot. Thus soot can negatively affect visibility both directly, by light absorption and scattering, and indirectly, through catalysis of SO2 oxidation. © 1989 Elsevier Science Publishing Co., Inc.