The anthropogenic nitrogen oxides emissions in China in the period 1990-1998

NO_x emissions arising from rapid economic growth and large fossil fuel energy consumption in China have increased ambient concentration of NO_x, regional levels of acid deposition and tropospheric ozone, and have drawn much attention by scientists domestic and abroad. In this paper, NO_x emissions in China in the period 1990-1998 were presented on the basis of provincial historical energy consumption and specific NO_x emission factors for different sectors and fuel types. Specially, the regional and sectoral NO_x emission inventories in 1998 were developed and discussed. NO_x emissions in China increased from 8.4Mt in 1990 to 11.18Mt in 1998. However, compared with those of 1995 and 1996, NO_x emissions in 1998 decreased by an amount of 0.12 and 0.82Mt because of descending energy consumption, which can be partly explained by Asian financial crisis and domestic economic restructure. NO_x emissions by fuels were dominated by coal combustion (72%) and sectoral emissions were by industry (41%), electric power (38%) and transportation (13%). NO_x emissions in seven provinces exceeded 0.5Mt, namely Hebei, Jiangsu, Liaoning, Shandong, Shanxi, Guangdong and Henan, while NO_x emissions in Hainan, Ningxia and Qinghai provinces were less than 0.1Mt. The provinces with hightest NO_x emissions intensities (>10t km^-2yr^-1) were Shanghai, Tianjin and Beijing. In general, NO_x emissions were mainly concentrated in the populated and industrialized areas of China, namely the Eastern Central and Southeastern provinces.