Comprehensive Study of Lead Pollution in Shanghai by Multiple Techniques

摘要

Aerosol samples of PM_(10) particulates were examined with particle-induced X-ray emission (PIXE and micro-PIXE), inductively coupled plasma-mass spectrometry, and X-ray absorption fine structures (XAFS) to investigate atmospheric Pb concentrations and its chemical species and to decide the source assignment. From the elemental analyses, lead concentrations were averaged at 369 and 237 ng(centre dot)m~(-3) in aerosol samples of PM_(10) collected from 19 monitor sites in Shanghai in the winter of 2002 and 2003, respectively. The XAFS results show that major chemical forms of the lead particulates are probably PbCl_(2), PbSO_(4), and PbO. A calculation of isotope ratio and chemical mass balance of the PM_(10) samples revealed that the atmospheric lead particulates in Shanghai in the two periods were mainly from coal combustors, iron and steel plants, and automobile exhausts, with coal combustion dominating the lead pollution after the phasing out of leaded gasoline in 1997 in Shanghai.