Pollution status and trend analysis of the main atmospheric pollutants in five national central cities in China

摘要

Beijing, Tianjin, Shanghai, Guangzhou and Chongqing are the five national central cities in China. Base on the method of Spearman rank correlation, concentrations of the main atmospheric pollutans declined generally from 2002 to 2013 in the five cities and the decreasing trends of SO_2 were more significant than those of NO_2, probably due to the wide use of desulfurization and increasing number of vehicles. However, the air pollution was still serious in 2013 and the contamination caused by atmospheric particulate matter was prominent. Transformations between gaseous pollutants (including SO_2 and NO_2) and PM10 were observed and different among the cities. The variations of PM10 were closely related to SO_2 in Shanghai and NO_2 in Tianjin, respectively. While in other three cities, both of SO_2 and NO_2 probably contributed to the formation of PM_10.