Aerosol size distribution and elemental composition in urban areas of Northern China

Based on monitoring data collected in the northern cities of China since 1980, the particle size spectra, distribution modes and the elements distribution features are discussed in this article. It is found that the major aerial contaminant in urban aerosol of northern China is fine dust. It makes up about 70% of the total suspended particulate matter by mass concentration. The spectra of aerosol particles in the range 0.5–15.0 μm are all unimodal structures. Regardless of narrow or broad profiles, their peak values fall between 0.5 and 1.0 μm, while their surface area spectra present a trimodal structure. The three peaks are in the range 0.5-1.8, 2–8 and 10–20 μm, respectively. Of these peaks, the surface area concentration of particulates had made a large contribution to the first and the second peaks. The shape of mass distribution also presents a trimodal structure, and the positions of the three peaks are the same as those found in the surface area pattern. Mineral elements mainly exist in large size particles. The anthropogenic pollution elements, however, are contained in corpuscles (< 2.0 μm). Compared to the situation in winter, some element concentrations of particulates in summer are found to have generally decreased.