宜昌市PM10水溶性无机组分与硫酸盐的δ34S值变化特征

Characteristics of Water-Soluble Inorganic Components and Stable Sulfur Isotope Compositions in PM10 in the Yichang City

利用TH-150中流量颗粒物采样器,在2012年12月至2013年3月采集了宜昌市PM10样品,测试了水溶性无机离子和硫酸盐硫同位素组成。研究显示,宜昌市PM10主要的水溶性无机离子有SO4^2-、NO3^-、NH4^＋、Na^＋、Ca^2＋,二次离子（SO4^2-＋NO3^-＋NH4^＋）的含量与总水溶性无机离子质量浓度比值超过70%,说明宜昌市大气二次污染严重;无机离子冬季以（NH4）2SO4、NH4NO3、Ca SO4和Na2SO4为主,春季则以NH4NO3、Ca SO4、Na2SO4为主。冬季白天PM10中硫酸盐δ^34S值为2.8‰~4.7‰,夜间为2.9‰~4.8‰;春季白天为1.5‰~4.7‰,夜间为1.7‰~4.0‰,昼夜变化不明显,春季比冬季偏负。研究结果表明,宜昌市PM10的来源主要有燃煤、机动车尾气、道路二次扬尘,春季还受农业活动和生物源释放影响。

In this study,PM10 samples were collected by TH-150 middle flow sampler during Dec.2012 and Mar.2013 in the Yichang City.These samples contain SO4^2-,NO3^-,NH4^＋,Na^＋,Ca^2＋ as major water soluble inorganic ions.Among them,secondary ions（SO4^2-＋NO3^-＋ NH4^＋） accounted for more than 70 percent of total water soluble inorganic ions,indicating the secondary pollution was serious in the Yichang City.These inorganic ions mainly occurred as（NH4）2SO4,NH4NO3,CaSO4 and Na2SO4 in wintertime,and formed NH4NO3,CaSO4,Na2SO4 in springtime.In winter,the δ^34S values of sulfate ranged from 2.8‰ to 4.7‰ and from 2.9‰ to 4.8‰ in the daytime and in the nighttime,respectively.In spring,the δ^34S ratios ranged from 1.5‰ to 4.7‰ and from 1.7‰ to 4.0‰ in the daytime and in the nighttime,respectively.The sulfur isotopic compositions of PM10 samples are similar in the daytime and nighttime.However,and the δ^34S values in spring were slightly negative than those in winter.The chemical and isotopic compositions of PM10 samples from the Yichang City suggested that the coal burning,vehicle exhaust,and re-entrainment of road dust are the dominant sources of the PM10 in Yichang City.In spring,agriculture activity also has contribution for PM10.