乌鲁木齐市大气降尘环境磁学特征  

Magnetic properties of Urumqi dustfall and its implication to urban pollution

作　　者：徐莉[1,2] 李艳红[1,2] 

机构地区：[1]新疆师范大学地理科学与旅游学院,新疆乌鲁木齐830054 [2]新疆维吾尔自治区重点实验室"新疆干旱区湖泊环境与资源实验室",新疆乌鲁木齐830054

出　　处：《干旱区地理》2014年第2期274-280,共7页Arid Land Geography

基　　金：国家自然科学地区基金项目资助(41161010);新疆师范大学研究生创新基金项目(20121203)资助

摘　　要：应用环境磁学方法研究了乌鲁木齐市大气自然降尘所含磁性矿物的磁学特征,同时对该市实施"煤改气"工程前后的空气质量变化进行对比。结果表明:(1)大气降尘样品的磁化率(x)平均值为508.77×10^(-8)m^3/kg,频率磁化率(x_(fd)%)平均值为2.17,表明该市降尘样品中载磁矿物主要为亚铁磁性矿物,超顺磁(SP)性颗粒物的含量较低;(2)X值、SIRM和SOFT都有较为显著的季节变化,其数值夏季低于冬季。且降尘样品中磁化率和软剩磁与饱和等温剩磁(SIRM)呈正相关,说明低矫顽力亚铁磁性矿物是样品剩余磁性的主要载体;(3)大气降尘磁化率与空气污染物浓度随时间的变化曲线特征趋势相一致,且2011年较2012年污染程度明显减轻;(4)该市大气降尘样品冬季可能主要受控于供暖期燃煤排放的废气。Magnetic susceptibility has been ascertained to be a valid method in identifying pollution source and sedimentary process of fine-grained PMs （ 〈 10 μ m） in the air. Thereafter, magnetism has been collectively used to monitor air pollution. In this paper a set of environmental magnetic parameters was measured on the monthly collect- ed dustfall samples, which were collected from 2012 to 2013 at campus of Xinjiang Normal University, Urumqi, Xin- jiang, China, and compared air quality index changes since the city implemented ＂coal to gas＂ from 2011-2012. All the samples were subjected to measurement of low-field magnetic susceptibility using a Bartington MS2, such as magnetic susceptibility （X）, frequency dependent susceptibility （Xfd %）- Samples were also subjected to magnetic measurement of isothermal remanent magnetization （ IRM ）, IRM acquired in a field of 1 T was regarded as satura- e parameters have repeatedly been and concentration of ferrimagnetism in atmospheric air particulate were summarized as follows： the magnetic susceptibility used to identify magnetic composition, grain size matter（PM） samples. The results from the study （X） and frequency dependent susceptibility （X：d%） reveal that the dominant magnetic minerals are ferromagnetic mineral and the lower content of super-paramagnetic （SP）, which were characterized by high （average 508.77 ×10^-8 m^3/kg）, frequency dependent susceptibility （average 2.17%）. χ,SIRM and SOFT changed obviously in season,and whose values in summer is lower than that in win- ter. Magnetic susceptibility values of dustfall have significantly positive correlation with Soft IRM and saturation isothermal remanent magnetization （ SIRM ）, suggesting that the ferromagnetic minerals are the main magnetic carri- ers. Correlations between magnetic susceptibility and temporal variations of concentration of air pollutants indicate that the level of air pollution degree was reduced from 2011 to 2012. the coal burning for heating is

关 键 词：大气降尘 环境磁学 空气污染指数 乌鲁木齐 

分 类 号：X513[环境科学与工程—环境工程]