西安市大气降尘的磁学特征及其环境意义  

Magnetic Properties of Dustfall and Its Environmental Significance in Xi'an,China

作　　者：张俊辉[1] 张健[2,3] 王晓静[4] 王瑾[1] 夏敦胜[5] 

机构地区：[1]宝鸡文理学院陕西省灾害监测与机理模拟重点实验室,陕西宝鸡721006 [2]西北大学城市与环境学院,陕西西安710127 [3]西北大学丝绸之路研究院,陕西西安710069 [4]西安科技大学地质与环境学院,陕西西安710120 [5]兰州大学西部环境与气候变化研究院,甘肃兰州730000

出　　处：《中国沙漠》2015年第3期699-706,共8页Journal of Desert Research

基　　金：陕西省教育厅科研计划项目(12JK0476)

摘　　要：对西安市电子二路(XZ)和长安区郭杜镇(XCA)两个样点2012年1月至2013年12月连续两年的大气降尘进行详细系统环境磁学实验分析。结果表明:西安市大气降尘中磁性矿物含量相对较高,主要的磁性矿物为多畴和假单畴的低矫顽力亚铁磁性矿物,并伴有少量的赤铁矿等高矫顽力的硬磁性矿物,磁畴主要由粗颗粒的MD(多畴)和PSD(准单畴)组成。XZ样点大气降尘的磁性浓度和磁性矿物的粒径大于XCA样点,表明城市不同功能区污染源类型存在差异。西安市大气降尘磁性矿物含量表现出明显的季节变化的特征,5—8月(夏季)磁性矿物的浓度明显较低,10月到次年的1月(冬季)是磁性矿物浓度最大的时期,这主要与采暖期排放源的变化有关,另外,西安市特殊的地形和气象因素对大气粉尘的扩散产生重要的影响,导致冬季粉尘的富集。Environmental magnetic measurements were carried out on the dustfall samples from Xi'an.These samples were collected in every month from January 2012 to December 2013 at XZ and XCA sites.The magnetic parameters(χlf,χARM,SIRM,FORC diagram and magnetic hysteresis parameters)indicate a relatively high concentration of ferrimagnetic minerals in Xi'an,dominated by multiple domain(MD)and pseudo-single domain(PSD)ferrimagnetic minerals.The concentration of magnetic minerals in XZ site is higher than those in XCA site,suggesting the different pollution sources in different functional district of Xi'an.The concentration of magnetic minerals has significant changes according to the seasons in each year,and the values rise from October to January of next year,and decrease in summer,which mainly not only come from the pollution of coal-burning,but also are influenced by the special topography and meteorological conditions.

关 键 词：大气降尘 磁学特性 污染 西安市 

分 类 号：X513[环境科学与工程—环境工程]