【作者】 张春霞； 黄宝春； 李震宇； 刘贺；

【Author】 Zhang Chunxia Huang Baochun Li Zhenyu Liu he Institute of Geology and Geophysics Chinese Academy of Sciences,Beijing 1000029,China

【机构】 中国科学院地质与地球物理研究所岩石圈演化国家重点实验室古地磁学与年代学实验室；

【摘要】 近年来,随着日益加速的城市化和工业化进程,大都市及周边的大气环境质量日益受到关注.本文通过对北京首都机场高速公路旁树叶样品的磁学研究,揭示出:高速公路旁树叶样品中的磁性矿物为准单畴的磁铁矿,平均粒径介于0.2～5μm之间;树叶样品中磁性矿物的含量和粒径随着与高速公路沥青路面距离的增大而减小,现代交通污染磁响应高值区局限于距高速公路沥青路面大约2 m宽的条带状区域内.此外,尽管磁化率测量可作为一种简单、快速且廉价的交通污染检测方法,但当污染样品磁性很弱时,饱和等温剩磁(SIRM)可取代磁化率而成为大气微粒含量的指示器.因此,多参数岩石磁学研究能有效地确定微粒的含量及粒度特征,是一种有效的且经济、快速的大气污染监测手段.更多还原

【Abstract】 This is a report on magnetic properties of highroad-side tree(Pinus pumila Regel) leaves collected along an expressway linking Beijing City and the Capital International Airport and further focus on their environmental contributions.A series of rock magnetic experiments show that the primary magnetic mineral of leaf samples was identified to be magnetite,in the pseudo-single domain(PSD) grain size range 0.2—5.0μm.On the other hand,magnetite concentration and grain size in leaves are ascertained to decrease with increasing of sampling distance to highroad asphalt surface,suggesting that high magnetic response to traffic pollution is localized within a distance of some two meters away from highroad asphalt surface.Although magnetic susceptibility is ordinarily regarded as a simple,rapid and low-cost method for monitoring traffic pollution,saturation isothermal remanent magnetization(S1RM) can be treated as a valid proxy for monitoring of air particulate matter(PM) when samples are magnetically weak.It is believed that a synthetic rock magnetic study is an effective method for determining concentration and grain size of ferromagnets in the atmospheric PM,and then it should be a rapid and feasible technique for monitoring atmospheric pollution.更多还原