To investigate the characteristic and sources of the fine particulate matter(PM2.5),and the major sources affecting particulate air pollution in Shanghai,China,the individual aerosol particles were analyzed using the synchrotron radiation micro-beam X-ray fluorescence analysis(?-SXRF),and the PM2.5 multi-elements were determined by the inductively coupled plasma mass spectrometer(ICP-MS).The results show that the mass concentration and chemical elements have seasonal variation,and the enrichment factors show that the chemical elements in the inhalable particles could come from the earth crust and anthropogenic pollution.The extent of metal pollution was assessed by comparing the measured concentrations with those reported in the literature.Nine categories of PM2.5 pollution sources identified at the center of Shanghai show that the vehicle exhaust,emission of metallurgic industry and coal combustion are important.
In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores-cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was applied to analyze the individual PM2.5 particles collected from Shanghai air in the winter of 2007.Eight categories of emission sources were recognized in these individual particles.The source identification shows that most of the analyzed PM2.5 particles are derived from vehicle exhaust and metallurgical emissions.This suggests that the important emission sources of PM2.5 in Shanghai air would be vehicle exhaust and metallurgical activities.
The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites (6 traffic, 5 industrial, and 6 residential sites), and 3 suburban sites to assess the lead pollution in fine particulate matter (PM2.5) after phasing out leaded gasoline in Shanghai. Compared with Pb levels reported in other places, the Pb pollution in Shanghai is still serious after phasing out leaded gasoline, which remains at high concentration range (213–176 ng/m3) in PM2.5 in winter. Significant spatial variation of Pb concentrations and strong seasonal variation of higher Pb concentration in winter than that in summer were detected. The size distribution of Pb in particulate matter has a unimodal mode that peaks at approximately 0.154–1.59 μm particle diameter, indicating that Pb is mainly concentrated in fine fraction. Lead in the fine fraction is enriched by a factor of 103–104 relative to Pb abundance in crust. Eight categories of Pb pollution sources were identified in the PM2.5 in the winter of 2007 in Shanghai. The important emission sources among them are vehicle exhaust derived from combustion of unleaded gasoline, metallurgic industry emission, and coal combustion emission.
LI XiaolinZHANG YuanxunTAN MingguangLIU JiangfengBAO LiangmanZHANG GuilinLI YanIIDA Atsuo
