Prajapati Santosh Kumar, Pandey Sudhir Kumar, Tripathi B D
Pollution Ecology Research Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India.
Environ Monit Assess. 2006 Sep;120(1-3):169-75. doi: 10.1007/s10661-005-9055-y. Epub 2006 Jun 9.
Biomonitoring of vehicle-derived particulates is conducted by taking magnetic measurements of roadside tree leaves. Remanent magnetization (IRM(300 mT)) of more than 400 Delbergia sissoo leaves was determined and IRM(300 mT) normalized for the leaf area. The normalized 2-D magnetization as shown by results is dominantly controlled by the tree's distance to the road. The spatial and temporal variations of vehicle-derived particulates were mapped using magnetic analysis. 2D-magnetizations values were higher for leaves collected adjacent to major road sections than for those from village road suggesting vehicle emissions, rather than resuspended road dust, as the major cause of magnetic particles of roadside tree leaves. Vehicles derived particulates are responsible for tree leaf magnetism, and the leaf magnetizations values fall significantly from high values proximal to the roadside to lower values at the distal side. This suggests the ability of trees to reduce particulates concentrations in the atmosphere. The rainfall produces a net decrease in the leaf magnetic dust loadings.
通过对路边树叶进行磁性测量来开展车辆衍生颗粒物的生物监测。测定了400多片印度黄檀树叶的剩余磁化强度（IRM(300 mT)），并将IRM(300 mT)按叶面积进行归一化处理。结果所示的归一化二维磁化强度主要受树木与道路距离的控制。利用磁性分析绘制了车辆衍生颗粒物的时空变化图。与乡村道路树叶相比，主要路段附近采集的树叶二维磁化强度值更高，这表明车辆排放而非道路扬尘再悬浮是路边树叶磁性颗粒的主要来源。车辆衍生颗粒物导致树叶产生磁性，树叶磁化强度值从路边附近的高值显著下降到远端的低值。这表明树木具有降低大气中颗粒物浓度的能力。降雨使树叶磁性尘埃负荷净减少。
