Characteristics of trace elements and lead isotope ratios in PM2.5 from four sites in Shanghai

PM2.5 samples were collected in Shanghai at four sites with different typical land-uses. The sampling was done concurrently once per month from April 2004 to April 2005, and the ambient mass concentration, the elemental composition and the stable lead isotope ratios in these PM2.5 samples were determined. The annual average concentrations of PM2.5 samples at each site were 84+/-30, 65+/-20, 55+/-18, and 41+/-10 ug m-3, respectively, indicating there were severe air pollution levels in Shanghai. The site-to-site comparison of mass concentrations demonstrated that the contribution of stationary industrial emissions was more important than the mobile sources even in areas with heavy traffic use. The enrichment factor was calculated for each element and the comparison and discussion of elements with significant anthropogenic contributions between Shanghai and Tokyo suggested that the major source of PM2.5 in Shanghai was not traffic-derived emissions, but the stationary industrial contribution emitted from coal use. Moreover, the analysis of stable lead isotope ratios revealed only a slight difference within the samples at the four sites which fell well within the scope of coal composition difference, further confirming that the contribution from stationary industrial emissions to atmospheric lead pollution of PM2.5 was very substantial in Shanghai