北京市朝阳区大气降尘磁学特征及对空气污染物浓度的指示

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...

Magnetic properties and indicator of concentration of pollution of atmospheric dust in Chaoyang,Beijing

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.