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LEE XinQing 《科学通报(英文版)》2010,55(16):1667-1673
Low molecule weight carboxylic acids are ubiquitous and important chemical constituents in the troposphere.Seven carboxylic acids in the rainwater of Guiyang and Shangzhong were simultaneously determined by ion chromatography from April 2006 to April 2007.Formic, acetic and oxalic acids were found to be the predominant carboxylic acids.Their volume weighted average concentration (VWA) in the rainwater of Guiyang were 14.24 μmol/L, 9.35 μmol/L and 2.79 μmol/L, respectively;as compared to 4.95 μmol/L, 1.35 μm... 相似文献
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Low molecular weight (LMW) organic acids are important and ubiquitous chemical constituents in the atmosphere. A comprehensive
study of the chemical composition of precipitation was carried out from June 2007 to June 2008 at a rural site in Anshun,
in the west of Guizhou Province, China. During this period, 118 rainwater samples were collected and the main LMW carboxylic
acids were determined using ion chromatography. The average pH of rainwater was 4.89 which is a typical acidic value. The
most abundant carboxylic acids were formic acid (volume weight mean concentration: 8.77 μmol L−1) and acetic acid (6.90 μmol L−1), followed by oxalic acid (2.05 μmol L−1). The seasonal variation of concentrations and wet deposition fluxes of organic acids indicated that direct vegetation emissions
were the main sources of the organic acids. Highest concentrations were observed in winter and were ascribed to the low winter
rainfall and the contribution of other air pollution sources northeast of the study area. The ratio of formic and acetic acids
in the precipitation ([F/A]
T
) was proposed as an indicator of pollution source. This suggested that the pollution resulted from direct emissions from
natural or anthropogenic sources. Comparison with acid precipitation in other urban and rural areas in Guizhou showed that
there was a decreasing contribution of LMW organic acids to free acidity and all anions in rainwater from urban to remote
rural areas. Consequently, it is necessary to control emissions of organic acids to reduce the frequency of acid rain, especially
in rural and remote areas. 相似文献
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