An analysis of winds affecting air pollution concentrations in Hong Kong

A study of concentrations of SO2 and TSP has been performed in Hong Kong. The results were discussed from the standpoint of seasonal, monthly, and weekly variations and wind effects. The monthly mean SO2 concentrations were in the range of 16.6–43.7 μg m-3 and showed regular seasonal variations with the highest concentrations in summer and the lowest in autumn. On the other hand, the monthly TSP concentrations reached the highest (117.7 μg m-3) in December and the lowest (72.9 μg m-3) in June. The procedure was able to identify that the high SO2 concentrations were generally associated with the southwesterly and westerly winds, while the high TSP concentrations were usually related to the northerly and westerly winds. From 1983 to 1992, 85% of the total high and severe SO2 concentration days were observed when there were the SSW-WNW winds over Hong Kong; and 70% of the total severe TSP concentration days occurred in the days with the W-ENE winds. Finally, the proportion of the total SO2 concentrations contributed by each of the source regions was quantitatively estimated. On an average the power stations, industry, and automobiles, etc., are responsible for 40, 35, and 25% of the total SO2 concentrations in the urban air of Hong Kong, respectively.