AN ANALYSIS OF THE AEROSOLS IN THE LOWER-LEVEL ATMOSPHERE OVER BEIJING NORTHERN SUBURBS IN WINTER^*

The physical and chemical characteristics of the aerosol samples were studied.The samples were collected on the 3 platforms (at levels 8 m,100 m and 320 m respectively) of IAP (Institute of Atmospheric Physics,Chinese Academy of Sciences) observation tower during the periods from January 1 to 16 and from February 20 to March 2,2001.The concentrations of TSP (total suspended particles),chemical components and size distribution for aerosols were calculated.The effects of the meteorological conditions on the aerosol concentrations and its distributions werestudied.The main aerosol sources from which the aerosols in the samples collected came were investigated.The conclusion was drawn preliminarily as follows.The TSP concentrations decreased with height.Over 70% of the aerosol mass were distributed in the fine particle group (d2.1μm).The top 20 aerosol elements with high concentration are listed from high to low according to their concentrations,and they are S,Fe,Ca,K,A1,Na,Mg,Zn,Cl,Ba,P,Ti,Pb,Mn,As,Cu,V,Br,Cr,and Sb.The aerosol element concentrations decreased with height,too.The mass of volatile elements was mainly distributed in the fine particle group.The ion mass was distributed in the same way as the element mass.From the point of view of contribution to the air aerosols,both anthropogenic and natural sources are important for Beijing.