title: Chemical and sulfur isotopic composition of precipitation in Beijing, China.
abstract: China is experiencing serious acid rain contamination, with Beijing among the worst-hit areas. To understand the chemical feature and the origin of inorganic ions in precipitation of Beijing, 128 precipitation samples were collected and analyzed for major water-soluble ions and δ(34)S. The pH values ranged from 3.68 to 7.81 and showed a volume weighted average value (VWA) of 5.02, with a frequency of acid rain of 26.8 %. The VWA value of electrical conductivity (EC) was 68.6 μS/cm, which was nearly 4 times higher than the background value of northern China. Ca(2+) represented the main cation; SO4 (2-) and NO3 (-) were the dominant anion in precipitation. Our study showed that SO4 (2-) and NO3 (-) originated from coal and fossil fuel combustion; Ca(2+), Mg(2+), and K(+) were from the continental sources. The δ(34)S value of SO4 (2-) in precipitation ranged from +2.1 to +12.8‰ with an average value of +4.7‰. The δ(34)S value showed a winter maximum and a summer minimum tendency, which was mainly associated with temperature-dependent isotope equilibrium fractionation as well as combustion of coal with relatively positive δ(34)S values in winter. Moreover, the δ(34)S values revealed that atmospheric sulfur in Beijing are mainly correlated to coal burning and traffic emission; coal combustion constituted a significant fraction of the SO4 (2-) in winter precipitation.
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China. zhuguangxu@mail.gyig.ac.cn.|State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China. zhuguangxu@mail.gyig.ac.cn.
authors.forename: Guangxu
authors.initials: G
authors.lastname: Zhu
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China. guoqj@igsnrr.ac.cn.
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Tongbin
authors.initials: T
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.
authors.forename: Yunchao
authors.initials: Y
authors.lastname: Lang
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Marc
authors.initials: M
authors.lastname: Peters
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Tian
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Hanzhi
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Chunyu
authors.initials: C
authors.lastname: Wang
mesh_terms: D015258:Acid Rain / Q000032:analysis*; D000068476:Beijing; D002681:China; D004784:Environmental Monitoring; D012621:Seasons; D013455:Sulfur / Q000737:chemistry; D013460:Sulfur Isotopes / Q000737:chemistry*
chemical_list: D015258:Acid Rain; D013460:Sulfur Isotopes; D013455:Sulfur
keywords: Beijing; Chemical composition; Precipitation; Sources; Sulfur isotope