Volume 6, No. 3, September 2006, Pages 268-280 PDF(384 KB)
Physicochemical Characterization and Origin of the 20 March 2002 Heavy Dust Storm in Beijing
Renjian Zhang1, Zifa Wang2, Zhenxin Shen3, S. Yabuki4, Y. Kanai5, A. Ohta5
1 Key Laboratory of Regional Climate-Environment Research for Temperate East Asia (REC-TEA), Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 100029, China
2 Nansen-Zhu International Research Centre, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 100029, China
3 Xi’an Jiaotong University, Xi’an, China
4 The Institute of Physical and Chemical Research, Wako, Saitama, 351-0198 Japan
5 Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology
This study characterized the profiles of particles collected during a dust-storm (DS) period in Beijing on 19-21 March 2002, which was one of the heaviest episodes in the previous decade. Several determinations of particle measurements were observed, including total mass concentrations, particle size distributions, dry deposition flux, and chemical ions concentrations. The TSP concentrations reached an extremely high peak value of 12 mg/m3 in DS period, and especially showed a characteristic increase in the size range of coarse particles (> 2.0 μm). The mass concentrations of coarse particles during DS period accounted for 91% of total particles, compared to 61% on non-DS days. The dry deposition mass flux of the dust storm reached 17.5 g/m2-d on 20 March in Beijing. Additionally, the transported pathway of the pollutants was investigated by using backward trajectory analysis. The result of analysis indicated that the high level of dust sand originated from the arid regions of southern Mongolia, passing through central Inner Mongolia, Shanxi Province, and then to Beijing. Concentrations of Cl−, NO3−, and SO42− in TSP were about 10 times higher in DS period than non-DS, probably because of some atmospheric processes enhancing chemical accumulation in the transported aerosols.
Dust storm; Size distribution; Number concentration; Backward trajectory analysis.