Isotopic Determinations and Source Study of Lead in Ambient PM2.5 in Beijing
北京大气PM2.5中铅的同位素测定和来源研究

Fine atmospheric aerosol(PM2.5) samples were collected on quartz filter in spring 2003 in Beijing,and multiple elements,organic carbon,elemental carbon,and lead isotopes were subsequently measured.Sample groups classified using cluster analysis method were discussed in conjunction with meteorological information.Two episodes of lead pollution were identified and described.Both episodes were featured by high lead content and low 206Pb/207Pb ratio.Concentration of elements such as Al,Ca,K varied differently from that of lead,implying soil dust a minor source of lead in air.Based on the variation correlation among Pb,As,Zn,Se,Al,Ca,it was induced that both episodes were dominated by non-ferrous industrial emission and coal combustion,the episode from February 28 to March 2,2003 had more coal combustion and less non-ferrous industry contributions.After phase-out of leaded petrol,non-ferrous industry and coal combustion appeared as the major source of aerosol lead pollution in Beijing.