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Abstract: This paper presents results of measurements of tropospheric sulphur dioxide (SO2) from satellite over China during 2004–2009. SCIAMACHY/ENVISAT SO2 data products have been validated by ground based remote sensing instrument MAXDOAS in China, and with predictions of the atmospheric model GEOS–Chem. The spatial and temporal distribution of tropospheric SO2 over China is discussed in this study. The result shows that the SO2 load over East China is decreasing since strong control for pollution emission in 2007 for preparation of 2008 Olympic Games in China, while the SO2 load in West China is increasing all the way during 2004–2009, which might reflect that the anthropogenic activity was added to promote the economy development in west of China. Typical seasonal variation with high pollution levels in winter and low in summer is found in the northwest of China, while the inverse seasonal variation is found for the south of China. The characteristics of tropospheric SO2 over the major cities in China were explored and found that tropospheric SO2 was partly under control from 2007 because of the policy from China government for reduction in SO2 emissions in 2006. And the SO2 value shows remarkably decrease in most of the major cities after 2007 because strong control for the pollution emission for 2008 Olympic games. Guangzhou city shows high SO2 pollution levels in summer time, since most of the coal power plants and thermal power industry are located to the south of Guangzhou city and southerly winds dominate during summer time. [Copyright &y& Elsevier]

Abstract: Daily total suspended particulate (TSP), particle size smaller than 100μm and particle size smaller than 2.5μm (PM2.5) aerosol samples were collected at two sites in Shanghai in four seasons from September 2003 to January 2005. Concentrations of the water-soluble ions (SO4 2−, NO3 −, Cl−, F−, PO4 3−, HCOO−, CH3COO−, NO2 −, MSA, C2O4 2−, NH4 +, Ca2+, Na+, K+, Mg2+) were measured for a total of 202 samples. Daily TSP and PM2.5 mass concentrations ranged from 66.1 to 666.8μgm−3 and 17.8 to 217.9μgm−3, with annual average concentrations of 230.5 and 94.6μgm−3, respectively. The sum of ions contributed an average of 26% and 32% of TSP and PM2.5 mass concentrations, respectively. In PM2.5, the concentration of the major ions followed the order of SO4 2−>NO3 −>NH4 +>Cl−>Ca2+>K+, while in TSP was SO4 2−>NO3 −>Cl−>Ca2+>NH4 +>Na+. These major ions were mainly in the form of (NH4)2SO4, Ca(NO3)2, CaCl2, and CaSO4 in aerosol particles. The aerosol was slightly acidic in the fine particle size range, and alkaline in the coarse mode. Seasonal variation of ion concentrations was significant, with the highest concentrations observed in winter and spring and the lowest in summer and autumn. Three types of air masses, i.e. marine, mixing, and continental, were frequently observed, and their distribution in four seasons might result in the clear seasonal variation. It is Shanghai that has the highest NO3 −/SO4 2− value among all of those cities in China, indicating that as the biggest city in China the mobile source of the air pollution becomes more and more predominant. However, stationary emissions were still the dominant source in Shanghai indicated by the NO3 −/SO4 2− ratio of lower than 1. The formation of NO3 − was largely from the gas-phase photochemical reaction in the cold season, and from the heterogeneous reaction in the warm season, while the formation of SO4 2− might be from the heterogeneous reaction in the entire year round. NH4 +, K+, Cl−, NO3 −, and SO4 2− were mainly influenced by the anthropogenic emissions in land, meanwhile Cl− and SO4 2− might be partly influenced by the sea. Na+, Mg2+, and Ca2+ were derived from both inland crustal and marine sources. Chloride depletion was found especially in summer. The air pollution in Shanghai has proved to be under the influence of both the local emissions and the long-range transport from outside areas. [Copyright &y& Elsevier]