北京秋季大风条件下大气气溶胶的尺度谱分布特征

The Element Size-Spectrum Distribution of Atmospheric Aerosol in Strong Autumn Winds over Beijing

Atmospheric aerosol samples collected in Beijing during 17-21 September 2004 were analyzed using the proton-induced X-ray emissions (PIXE) method, yielding concentrations of 20 elements. Analyzing the aerosol element size-spectrum distribution, enrichment factor (EF) and source over Beijing showed that under strong wind weather conditions, there were double peak distributions in the element size-spectra of Cu, S, K, Mn, As, Br, and Pb: one in fine mode and another in coarse mode. The peak in fine mode resulted from local emissions related to human activities, while the peak in coarse mode was caused by long range transport. The EF values of elements Ni, Cu, Zn, As, Se, Br, and Pb were relatively high, suggesting an evident characteristic polluted by regional aerosol. Results from factor analysis indicated that soil dust, coal-burning, industry and vehicle emissions contributed considerably to the autumn aerosol pollution in Beijing.