昆明市城区旱季尘土磁化率特征及环境意义

Magnetic Characteristics of Street Dust in Drought Season of Kunming and Its Environmental Significance

分析了昆明市区旱季道路尘土样品磁化率特征。结果表明，样品的Xlf的变化范围为96×10^-4-9×10^-4m3／kg，平均值为46．5×10^-4m3／kg，删值变幅为0．3％～13．8％，平均为2．0％；磁化率数值由市中心区向郊区呈下降趋势，且城市不同功能区的磁化率值也存在明显差异，表明影响昆明市街道尘土磁化率因素的多元性，工业活动可能不是昆明市城区道路尘土磁性矿物颗粒最主要来源，而主要是来自市区日常生产与生活活动，特别是昆明市众多机动车辆产生的磁性颗粒物；道路尘土中磁性矿物含量较高，以人为源为主，重金属污染较重。

The paper reveals the magnetic characteristics of street dust in a drought season of Kunming. The street dust sample magnetic susceptibility are ranging from 96-9×10^-8m3/kg, and the average value is 46.5×10^-7m3/kg, meanwhile the Xfd are ranging from 0.3~13.8 % and the average value is 2.0%. These results suggest that the main magnetic minerals in the street dust are in a high level and mainly from human activities, and the heavy metal become seriously pollution. The data demonstrates that the magnetic susceptibility of street dust is in the decline tendency from central of urban area to suburban districts, and the magnetic susceptibility in different urban area is clearly different. It indicates that different factors influence on the magnetic susceptibility in the street dust of Kunming. The main magnetic minerals in the street dust of Kunming may not from the main sources of industrial activities, but from the urban area daily manufacture and living activities, especially from the numerous motor vehicles. Kunming is a city which has few heavy industries and does not supply of heat in winter, whose magnetic susceptibility and heavy metal are mainly related to vehicles. This paper might be used as references for further researches for other cities.