Elemental concentrations and their size distributions of Beijing aerosol in January

Aerosol sampling was carried out at a city centre site and a suburb site in Beijing in January 1983. PIXE (Proton Induced X-ray Emission) compatible cascade impactors were employed. The samples were analysed for 20 elements by PIXE in Fudan University. It has been found that most of the elements have bi-mode size distributions with a gradual progression from mainly coarse mode Ca, Ti and Al to mainly fine mode Zn, As and Pb. Elements Cl, K, S and Si show most obvious bi-mode, of which Si and S are particularly interesting. The concentrations of coarse mode aerosol in the city centre are about 1.4 times as large as that in the suburb for most of the elements, while the concentrations of fine mode aerosol in the city centre differ greatly from that in the suburb and vary significantly among elements, indicating some industrial sources. The enrichment factors of elements indicate that the coal smoke has a large-scale influ-ence in North China.