Aerosol oxalate and its implication to haze pollution in Shanghai,China  

作　　者：Yilun Jiang Guoshun Zhuang Qiongzhen Wang Tingna Liu Kan Huang Joshua S.Fu Juan Li Yanfen Lin Rong Zhang Congrui Deng 

机构地区：[1]Center for Atmospheric Chemistry Study, Department of Environmental Science and Engineering, Fudan University [2]Department of Civil and Environmental Engineering,The University of Tennessee

出　　处：《Chinese Science Bulletin》2014年第2期227-238,共12页

基　　金：supported by the Great International Collaboration Project of MOST,China(2010DFA92230);the National Basic Research Program of China(2006CB403704);the National Natural Science Foundation of China(20877020 and20977017)

摘　　要：A total of 238 samples of PM2.5and TSP were analyzed to study the characteristics,sources,and formation pathways of aerosol oxalate in Shanghai in four seasons of 2007.The concentrations of oxalate were0.07–0.41 lg/m3in PM2.5and 0.10–0.48 lg/m3in TSP,respectively.Oxalate displayed a seasonal variation of autumn[summer[winter[spring in both PM2.5and TSP and was dominantly present in PM2.5in all samples.Correlation between oxalate and K?and high ratio of oxalate/K?suggested that biomass burning was a secondary source of aerosol oxalate in Shanghai,in addition to urban VOCs sources(vehicular and industrial emissions),especially in autumn.Secondary formation accounted for the majority of aerosol oxalate in Shanghai,which was supported by the high correlation of oxalate with nssSO42-,K?and NO3-,proceeding from different mechanisms.Relatively high ambient RH together with high cloud cover was found benefiting the secondary formation of aerosol oxalate.The in-cloud process(aqueous-phase oxidation)was proposed to be likely the major formation pathway of aerosol oxalate in Shanghai,which was supported by the high correlation of oxalate with nss-SO42-and K?,dominant residence of oxalate in droplet mode and result of favorable meteorological condition analysis.High correlation of oxalate and NO3-reflected the OH radical involved oxidation chemistry of the two species in the atmosphere and also suggested that gas-particle surface reactions and the evaporation–condensation process were both possible secondary formation pathways of aerosol oxalate in coarser particle mode([1.0 lm).As a major water-soluble organic compound in aerosols,concentration of oxalate showed a distinct negative correlation to the atmospheric visibility,which implied that aerosol organic compounds could play an important role in haze pollution as well as in air quality in Shanghai.A total of 238 samples of PM2.5 and TSP were analyzed to study the characteristics, sources, and formation pathways of aerosol oxalate in Shanghai in four seasons of 2007. The concentrations of oxalate were 0.07-0.41 μg/m3 in PM2.5 and 0.10-0.48 μg/m3 in TSP, respectively. Oxalate displayed a seasonal variation of autumn 〉 summer 〉 winter 〉 spring in both PM2.5 and TSP and was dominantly present in PM2.5 in all samples. Correlation between oxalate and K＋ and high ratio of oxalate/K＋ suggested that biomass burning was a second- ary source of aerosol oxalate in Shanghai, in addition to urban VOCs sources （vehicular and industrial emissions）, especially in autumn. Secondary formation accounted for the majority of aerosol oxalate in Shanghai, which was supported by the high correlation of oxalate with nss- SO42-, K＋ and NO3-, proceeding from different mecha- nisms. Relatively high ambient RH together with high cloud cover was found benefiting the secondary formation of aerosol oxalate. The in-cloud process （aqueous-phase oxidation） was proposed to be likely the major formation pathway of aerosol oxalate in Shanghai, which was sup- ported by the high correlation of oxalate with nss-SO42- and K＋, dominant residence of oxalate in droplet mode and result of favorable meteorological condition analysis. High correlation of oxalate and NO3- reflected the OH radical involved oxidation chemistry of the two species in the atmosphere and also suggested that gas-particle surface reactions and the evaporation-condensation process were both possible secondary formation pathways of aerosol oxalate in coarser particle mode （〉1.0 μm）. As a major water-soluble organic compound in aerosols, concentration of oxalate showed a distinct negative correlation to the atmospheric visibility, which implied that aerosol organic compounds could play an important role in haze pollution as well as in air quality in Shanghai.

关 键 词：草酸盐 气溶胶 上海 污染 灰霾 有机化合物 中国 气象条件分析 

分 类 号：X513[环境科学与工程—环境工程] O614.33[理学—无机化学]