摘要
应用环境磁学方法研究了2008年奥运会前后北京市朝阳区大气降尘及对照点表土样品的磁学特征.结果表明,所有样品中载磁矿物主要为低矫顽力的亚铁磁性矿物(主要为磁铁矿).但大气降尘样品的磁性颗粒粒度较表土偏粗;磁性矿物含量高于表土样品,大气降尘除来自于自然源外,更多为来自于人为因素的结果.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一致,说明大气降尘样品的磁学监测可以快速、准确地反映城市空气污染程度及其变化,同时揭示出北京市朝阳区大气降尘样品夏季主要来源于工业和交通,冬季主要受控于集中供暖期间煤燃烧排放的废气.快速的磁化率测量可以对空气污染指数有良好的指示作用.环境磁学参数随时间的变化特征显示,奥运期间各项污染物临时减排措施落实到位,对空气质量明显改善发挥了根本性作用.
Magnetic properties of atmospheric dusts collected during the period of Beijing Olympic Games in Chaoyang, and some topsoil samples were measured in order to disclose the source of air pollutants. Thermomagnetic, isothermal remanent magnetization and hysteresis measurements reveal that the dominant magnetic minerals are magnetite. Compared with topsoil samples, the concentration of magnetic particles in atmospheric dust samples are higher, and the magnetic grains are coarser. These results suggest that the magnetic particles in atmospheric dust samples come from anthropogenic rather than natural sources. Correlations between magnetic susceptibility and temporal variations of concentration of air pollutants indicate that magnetic particles mainly originated from industrial and traffic emissions in summer, whilst the coal burning for heating is a prominent contribution to the high magnetic mineral concentrations in winter. The temporal variations of magnetic parameters imply that the traffic control regulations in Beijing were essentially remarkable during the period of Olympic Games. These results suggest that magnetic measurement can serve as an efficient complementary tool for monitoring environmental pollution.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第1期151-162,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(40804014,20677059,40525013和40821091)资助
