南京北郊地区昼夜大气PM_(2.5)中硫同位素的组成及来源
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摘要
为研究南京地区昼夜大气PM_(2.5)中的硫同位素组成情况,采用Delta V Advantage同位素质谱仪技术对2016年3—4月南京北郊地区大气PM_(2.5)中昼夜δ~(34)S (硫同位素值)进行分析,结合大气颗粒物化学组成,追溯昼夜大气PM_(2.5)及SO_4~(2-)的来源.结果表明:南京北郊地区PM_(2.5)和SO_4~(2-)的整体变化趋势一致,具有同源性.南京北郊地区白天大气PM_(2.5)的δ~(34)S范围为4. 23‰～7. 16‰,平均值为5. 45‰±0. 91‰;晚上δ~(34)S的范围为4. 20‰～6. 73‰,平均值为5. 22‰±0. 83‰.相较于晚上,白天δ~(34)S略高主要与NO_x对SO_2的异相氧化反应和机动车尾气的排放有关.重霾天δ~(34)S范围为4. 20‰～7. 16‰,平均值为5. 39‰±0. 87‰;清洁天δ~(34)S范围为3. 14‰～5. 14‰,平均值为4. 03‰±0. 57‰.重霾天的硫源与燃煤、机动车尾气排放及NOx对SO2的异相氧化反应有关;而清洁天主要受到机动车尾气排放及SO_2与O_3均相氧化反应的影响.研究显示,南京北郊地区ρ(PM_(2.5))昼大于夜,而ρ(SO_4~(2-))夜大于昼,重霾天大气PM_(2.5)的δ~(34)S高于清洁天,这主要与NO_x、SO_2、O_3的相互转化有关.
To investigate the origin of PM_(2.5) and sulfate at a suburban site in the north of Nanjing City,PM_(2.5) samples were collected from March to April 2016,and the Delta V Advantage isotope ratio mass spectrometry was used to analyze the isotopic composition( δ~(34)S) of sulfur during the day and night time. The PM_(2.5) concentrations were higher at daytime than at night,while sulfate exhibited higher concentrations at night. In general,PM_(2.5) and sulfate had consistent temporal variation throughout the sampling period. The δ~(34)S values ranged from 4. 23‰ to 7. 16‰ with an average of 5. 45‰ ± 0. 91‰ during the daytime. The average δ~(34)S value at night was 5. 22‰ ±0. 83‰,ranging from 4. 20‰ to 6. 73‰. The δ~(34)S values of day and night changed in a similar trend. The higher δ~(34)S values during the daytime could be ascribed to heterogeneous oxidation of SO_2 by NO_x and motor vehicle emissions. The δ~(34)S values were 4. 20‰-7. 16‰ in haze days and 3. 14‰-5. 14‰ in clean days,with the averages of 5. 39‰±0. 87‰ and 4. 03‰±0. 57‰,respectively. We found that the sulfur in PM_(2.5) during haze days were mainly from coal burning,motor vehicle exhaust and heterogeneous oxidation of SO_2 by NO_x,while motor vehicle exhaust and homogeneous oxidation of SO_2 by O_3 were the major sources during clean days. The daytime concentration of PM_(2.5) in the northern suburbs of Nanjing City was greater than that of night,while the concentration of SO_4~(2-)was greater at night time. The average δ~(34)S value of ambient PM_(2.5) was higher during haze days than that during clean days,which was likely related to the different oxidation mechanisms of SO_2 during haze and clean days.
To investigate the origin of PM_(2.5) and sulfate at a suburban site in the north of Nanjing City,PM_(2.5) samples were collected from March to April 2016,and the Delta V Advantage isotope ratio mass spectrometry was used to analyze the isotopic composition( δ~(34)S) of sulfur during the day and night time. The PM_(2.5) concentrations were higher at daytime than at night,while sulfate exhibited higher concentrations at night. In general,PM_(2.5) and sulfate had consistent temporal variation throughout the sampling period. The δ~(34)S values ranged from 4. 23‰ to 7. 16‰ with an average of 5. 45‰ ± 0. 91‰ during the daytime. The average δ~(34)S value at night was 5. 22‰ ±0. 83‰,ranging from 4. 20‰ to 6. 73‰. The δ~(34)S values of day and night changed in a similar trend. The higher δ~(34)S values during the daytime could be ascribed to heterogeneous oxidation of SO_2 by NO_x and motor vehicle emissions. The δ~(34)S values were 4. 20‰-7. 16‰ in haze days and 3. 14‰-5. 14‰ in clean days,with the averages of 5. 39‰±0. 87‰ and 4. 03‰±0. 57‰,respectively. We found that the sulfur in PM_(2.5) during haze days were mainly from coal burning,motor vehicle exhaust and heterogeneous oxidation of SO_2 by NO_x,while motor vehicle exhaust and homogeneous oxidation of SO_2 by O_3 were the major sources during clean days. The daytime concentration of PM_(2.5) in the northern suburbs of Nanjing City was greater than that of night,while the concentration of SO_4~(2-)was greater at night time. The average δ~(34)S value of ambient PM_(2.5) was higher during haze days than that during clean days,which was likely related to the different oxidation mechanisms of SO_2 during haze and clean days.
引文
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[19]董群,赵普生,陈一娜.降雨对不同粒径气溶胶粒子碰撞清除能力[J].环境科学,2016,37(10):3686-3692.DONG Qun,ZHAO Pusheng,CHEN Yina.Impact of collision rremoval of rainfall on aerosol particles of different sizes[J].Environmental Science,2016,37(10):3686-3692.
[20]WANG Gehui,ZHANG Renyi,GOMEZ M E,et al.Persistent sulfate formation from London fog to Chinese haze[J].Proceedings of the National Academy of Sciences of the United States of America,2016,113(48):13630-13635.
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[27]HUNG Huiming,HOFFMANN M R.Oxidation of gas-phase SO2on the surfaces of acidic microdroplets:implications for sulfate and sulfate radical anion formation in the atmospheric liquid phase[J].Environmental Science&Technology,2015,49(23):13768-13776.
[28]ERIKSEN T E,THIEDEN H I D,DICH J,et al.Sulfur isotope effects.3.enrichment of34S by chemical exchange between SO2g and aqueous solutions of SO2[J].Acta Chemica Scandinavica,1972,26:975-979.
[29]TANAKA N,RYE D,XIAO Y,et al.Use of stable sulfur isotope systematics for evaluating oxidation reaction pathways and in-cloudscavenging of sulfur dioxide in the atmosphere[J].Geophysical Research Letters,1994,21(14):1519-1522.
[30]GUO Zhaobing,SHI Lei,CHEN Shanli,et al.Sulfur isotopic fractionation and source appointment of PM2.5in Nanjing Region around the second session of the Youth Olympic Games[J].Atmospheric Research,2016,174/175:9-17.
[2]SINHA B,HOPPE P,HUTH J,et al.Sulfur isotope analyses of individual aerosol particles in the urban aerosol at a central European site(Mainz,Germany)[J].Atmospheric Chemistry&Physics,2008,8(23):11-36.
[3]MARUFU L T,DICKERSON R,LI Zhanqing,et al.In situ measurements of trace gases and aerosol optical properties at a rural site in northern China during East Asian study of tropospheric aerosols:an international regional experiment 2005[J].Journal of Geophysical Research Atmospheres,2007,112(S22):321-341.
[4]白志鹏,张利文,朱坦,等.稳定同位素在环境科学研究中的应用进展[J].同位素,2007,20(1):57-64.BAI Zhipeng,ZHANG Liwen,ZHU Tan,et al.The status of applying stable isotope in the studies of environmental science[J].Journal of Isotopes,2007,20(1):57-64.
[5]GUO Zhaobing,WU Menglong,LIU Fengling,et al.Multiple sulfur and oxygen isotope compositions in Beijing aerosol environment in central Zhejiang,China[J].Science China:Earth Sciences,2014,57(11):2671-2675.
[6]HAN Xiaokun,GUO Qingjun,LIU Congqiang,et al.Using stable isotopes to trace sources and formation processes of sulfate aerosols from Beijing,China[J].Scientific Reports,2016,6(6):29958.
[7]ZHANG Miaoyun,WANG Shijie,MA Guoqiang,et al.Sulfur isotopic composition and source identification of atmospheric environment in Central Zhejiang,China[J].Science China:Earth Sciences,2010,53(11):1717-1725.
[8]贾梦唯,赵天良,张祥志,等.南京主要大气污染物季节变化及相关气象分析[J].中国环境科学,2016,36(9):2567-2577.JIA Mengwei,ZHAO Tianliang,ZHANG Xiangzhi,et al.Seasonal variations in major air pollutants in Nanjing and their meteorological correlation analyses[J].China Environmental Science,2016,36(9):2567-2577.
[9]赵辉,郑有飞,吴晓云,等.青年奥林匹克运动会期间南京市主要大气污染物浓度变化与分析[J].环境化学,2015,34(5):824-831.ZHAO Hui,ZHE Youfei,WU Xiaoyun,et al.Variation and analysis of air pollutants concentration in Nanjing during the Youth Olympic Games[J].Environmental Chemistry,2015,34(5):824-831.
[10]魏英,郭照冰,葛鑫,等.硫氧同位素示踪南京北郊大气PM2.5中硫酸盐来源[J].环境科学,2015,36(4):1182-1186.WEI Ying,GUO Zhaobing,GE Xin,et al.Tracing sources of sulfate aerosol in Nanjing northern suburb using sulfur and oxygen isotopes[J].Environmental Science,2015,36(4):1182-1186.
[11]MUKAI H,TANAKA A,FUIJI T,et al.Regional characteristics of sulfur and lead isotope ratios in the atmosphere at several Chinese urban sites[J].Environmental Science&Technology,2001,35(6):1064.
[12]OHIZUMI T,TAKE N,INOMATA Y,et al.Long-term variation of the source of sulfate deposition in a leeward area of Asian continent in view of sulfur isotopic composition[J].Atmospheric Environment,2014,140:42-51.
[13]SAKATA M,ISHIKAWA T,MITSUNOBU S,et al.Effectiveness of sulfur and boron isotopes in aerosols as tracers of emissions from coal burning in Asian continent[J].Atmospheric Environment,2013,67:296-303.
[14]LEUNG F Y,COLUSSI A J,HOFFMANM M R,et al.Sufur isotopic fractionation in the gas-phase oxidation of sulfur dioxide initiated by hydroxyl radicals[J].Journal of Physical Chemistry A,2001,5(34):8073-8076.
[15]NORMAN A L,ANLAUF K,HAYDEN K,et al.Aerosol sulphate and its oxidation on the Pacific NW coast:S and O isotopes in PM2.5[J].Atmospheric Environment,2006,40(15):2676-2689.
[16]郭安可,郭照冰,张海潇.南京北郊冬季PM2.5中水溶性离子以及碳质组分特征分析[J].环境化学,2017,36(2):248-256.GUO Anke,GUO Zhaobing,ZHANG Haixiao.Analysis of water soluble ions and carbon component in PM2.5in the northern suburb of Nanjing in winter[J].Environmental Chemistry,2017,36(2):248-256.
[17]刘广深,洪业汤.用稳定同位素方法探讨大气颗粒物中硫的来源[J].中国环境科学,1996,16(6):426-429.LIU Guangshen,HONG Yetang.Study on sources of sulfur in atmospheric particulate matter with stable isotope method[J].China Environmental Science,1996,16(6):426-429.
[18]YANAGISAWA F,SAKAI H.Thermal decomposition of barium sulfate-vanadium pentoxide-silica glass mixtures for preparation of sulfur dioxide in sulfur isotope ratio measurements[J].Analytical Chemistry,1983,55(6):985-987.
[19]董群,赵普生,陈一娜.降雨对不同粒径气溶胶粒子碰撞清除能力[J].环境科学,2016,37(10):3686-3692.DONG Qun,ZHAO Pusheng,CHEN Yina.Impact of collision rremoval of rainfall on aerosol particles of different sizes[J].Environmental Science,2016,37(10):3686-3692.
[20]WANG Gehui,ZHANG Renyi,GOMEZ M E,et al.Persistent sulfate formation from London fog to Chinese haze[J].Proceedings of the National Academy of Sciences of the United States of America,2016,113(48):13630-13635.
[21]UDHEER A K,RAMABADRAN R,DIPJYOTI D,et al.Diurnal and seasonal characteristics of aerosol ionic constituents over an urban location in western India:secondary aerosol formation and meteorological influence[J].Aerosol&Air Quality Research,2014,14(6):1701-1713.
[22]GALINDO N,YUBERO E.Day-night variability of water-soluble ions in PM10samples collected at a traffic site in southeastern Spain[J].Environmental Science and Pollution Research International,2017,24:805-812.
[23]YAO Xiaohong,CHAN C K,FANG M,et al.The water-soluble ionic composition of PM2.5in Shanghai and Beijing,China[J].Atmospheric Environment,2002,36(26):4223-4234.
[24]ARIMOTO R,DUCE R A,SAVOI D L,et al.Relationships among aerosol constituents from Asia and the North Pacific during PEM-West A[J].Journal of Geophysical Research,1996,101:2011-2023.
[25]石磊,郭照冰,姜文娟,等.南京地区大气PM2.5潜在污染源硫碳同位素组成特征[J].环境科学,2016,37(1):22-27.SHI Lei,GUO Zhaobing,JIANG Wenjuan,et al.Investigations on sulfur and carbon isotopic compositions of potential polluted sources in atmospheric PM2.5in Nanjing Region[J].Environmental Science,2016,37(1):22-27.
[26]HERAS A D L.Air pollution and anthropogenic climate change[M].Boca Raton:CRC Press,2014:173-194.
[27]HUNG Huiming,HOFFMANN M R.Oxidation of gas-phase SO2on the surfaces of acidic microdroplets:implications for sulfate and sulfate radical anion formation in the atmospheric liquid phase[J].Environmental Science&Technology,2015,49(23):13768-13776.
[28]ERIKSEN T E,THIEDEN H I D,DICH J,et al.Sulfur isotope effects.3.enrichment of34S by chemical exchange between SO2g and aqueous solutions of SO2[J].Acta Chemica Scandinavica,1972,26:975-979.
[29]TANAKA N,RYE D,XIAO Y,et al.Use of stable sulfur isotope systematics for evaluating oxidation reaction pathways and in-cloudscavenging of sulfur dioxide in the atmosphere[J].Geophysical Research Letters,1994,21(14):1519-1522.
[30]GUO Zhaobing,SHI Lei,CHEN Shanli,et al.Sulfur isotopic fractionation and source appointment of PM2.5in Nanjing Region around the second session of the Youth Olympic Games[J].Atmospheric Research,2016,174/175:9-17.