Observation and Analysis of SO2 and NO2 in Clean Air of Western China

Atmospheric SO2 and NO2 were sampled during the period from August 1994 to July 1995 by using filter packs (FP) method, and the concentrations of these gases were analysed with ion chromatography (IC) at Waliguan background baseline station (3810 m asl, 100o54’E, 36o17’N) of Qinghai Province, western China. It is found that the average concentrations of SO2 and NO2 are 0.147×10-9 and 0.055×10-9 ,respectively. There is a good correlation between SO2 and NO2 concentrations with a coefficient of 0.87, the ratio of SO2 to NO2 derived from the linear regression is about 2.6. Furthermore, the concentrations of SO2 to NO2 vary with seasons and wind directions. Higher concentrations are from easterly, and lower from westerly. The concentrations of SO2 and NO2 are lower in winter season and higher in summer.