沙尘暴对上海大气颗粒物中S、Cl、Ca化学种态的影响  

Impact of dust storm on chemical species of S,Cl and Ca in Shanghai atmosphere particles

作　　者：龙时磊[1,2,3] 刘可[1,2,3] 曾建荣[1] 曹玲玲[1,2,3] 包良满[1,3] 林俊[1] 李燕[1,3] 马陈燕 

机构地区：[1]中国科学院上海应用物理研究所,嘉定园区上海201800 [2]中国科学院大学,北京100049 [3]中国科学院核辐射与核能技术重点实验室,上海201800 [4]中国科学院高能物理研究所,北京100049

出　　处：《核技术》2013年第10期1-8,共8页Nuclear Techniques

基　　金：中国科学院知识创新工程重要方向项目(KJCX3.SYW.N3);国家自然科学基金(11079049、11005141)、国家自然科学基金青年项目(11105171)资助

摘　　要：为研究沙尘暴对上海大气颗粒物化学组成的贡献,本文连续采集了沙尘暴前、中、后期的颗粒物样品,使用同步辐射XRF以及XANES技术解析样品颗粒物中元素浓度以及S、Cl、Ca化学组成在沙尘暴过程中的变化。元素浓度变化结果显示,大气颗粒物样品地壳元素(Si、Al、Ca、K、Mg、Fe、Ti)随沙尘暴的到来大幅度增加,但是本地污染元素(S、Zn、Pb、Cu、V、Cr、As)却由于沙尘暴的"清洁"作用而降低。沙尘暴前后颗粒物样品中S元素主要以(NH4)2SO4的形式存在,Cl元素主要以有机氯的形式存在,而Ca元素主要以石膏形式存在。而沙尘暴期间的样品S元素主要存在形式是石膏(CaSO4·2H2O),Cl元素存在形式是有机氯及无机氯(–1价),Ca元素主要存在形式是CaCO3。结合后向轨迹,无机氯的来源可能是沙尘暴沿途(海面)携带的海盐成分,而石膏则是沙尘中富含的CaCO3在传输途中与SO42发生反应形成的。沙尘暴不仅给上海大气颗粒物带来了丰富的地壳颗粒物,而且沿途携带颗粒物,使得原本滞留的颗粒物随着沙尘暴输送到上海大气环境中,沙尘颗粒在传输过程中还会与当地污染颗粒物发生化学反应。Background： Dust storm originated from the northwest region of China brought dust particles for Shanghai every spring, which resulted in serious particulate pollution. However, the studies of the impact of dust storm on the Shanghai atmospheric aerosols were limited to the concentrations of ions and elements. It is considered that the chemical species of atmospheric aerosols were much more necessary for the evaluation of the impact of dust storm on the particulate pollution in Shanghai. Purpose： Based on the elements concentration variations, backward trajectories of air masses and chlorine, calcium, sulfur species in aerosols during the dust event, the impact of dust storm on the chemical species of aerosols in Shanghai was studied. Methods： Elements concentrations of the samples were analyzed by X-ray fluorescence （XRF） based on synchrotron radiation. To identify the potential importance of different source regions on aerosol composition during dust events, the air mass trajectories were calculated by using the model HYSPLIT version 4 developed by NOAA/ARL. Chemical species of S, C1, Ca were analyzed by synchrotron radiation X-ray absorption near edge structure （XANES）. Sulfur K-edge XANES is capable of distinguishing various sulfate species in a non-destructive way and we used linear combination fitting procedure to quantify the concentrations of sulfate species in PM. Results： Elements concentration variations during the dust storm period showed that crust elements （Si, A1, Ca, K, Mg, Fe, Ti） in particles increased substantially during dust storm. However, pollution elements （S, Zn, Pb, Cu, V, Cr, As） from local region decreased by the clean effect of dust storm. Combined XANES of S, C1, Ca in particulate samples with backward trajectories, the possible sources and reasons of their chemical species were studied. During dust storm, sulfur mainly existed as CaSO4-2H2O, C1 existed as organic chloride and CI-, Ca existed as CaCO3. In the samples of other days, sulfur was mainly existed as

关 键 词：沙尘暴 后向轨迹 X射线吸收近边结构(XANES)谱 颗粒物 

分 类 号：TL99[核科学技术—核技术及应用]