[Magnetic characteristics of street dust in Lanzhou and its environmental significance].
Lanzhou has been one of the most seriously polluted cities in the world due to its special geographical location and weather conditions, which make it an ideal place for urban pollution studies. A set of environmental magnetic parameters (chi lf, chi fd%, chi ARM, chi HIRM, SOFT and back field IRM) of the street dust sampled in Lanzhou during spring and summer 2005 were analyzed. These samples were collected along a main street across the urban area and a mountain route from foot to the top. Results demonstrate that the main magnetic minerals in the street dust are magnetite, maghaemite and haematite with some paramagnetic minerals. Plots of Mrs/Ms vs. Bcr/Bc and chi fd% vs. chi ARM/SIRM indicate that the main grain size of magnetic minerals in the street dust are pseudo single domain (PSD). The results reveal that the Lanzhou city is more polluted in spring than in summer. The main pollution sources are anthropogenic activities (81.9%) and natural dust (18.1%), especially the former. The spatial distribution of pollution is controlled by the topography and weather conditions.
Xia
Dun-sheng
DS
Key Laboratory of Desert and Desertification, Institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of Sciences, Lanzhou 730000, China. dsxia@lzb.ac.cn
Yu
Ye
Y
Ma
Jian-ying
JY
Wang
Guan
G
Yang
Li-ping
LP
Jin
Ming
M
Liu
Xiu-ming
XM
Chen
Fa-hu
FH
D000393:Air Pollutants / Q000032:analysis*; D002681:China; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring; D004787:Environmental Pollution / Q000032:analysis; D008280:Magnetics; D001335:Vehicle Emissions / Q000032:analysis*
D000393:Air Pollutants; D004391:Dust; D001335:Vehicle Emissions