A lead isotope record of shanghai atmospheric lead emissions in total suspended particles during the period of phasing out of leaded gasoline

The concentrations of lead as well as the stable lead isotope ratios were measured in the total suspended particles (TSP), collected at three monitoring sites in Shanghai, China, since 1995 ranging the period of phasing out of leaded gasoline. During all these years, the variation of lead concentrations in TSP showed the feature of site- dependence. In the traditionally industrial area of YangPu district, the concentrations were sometimes extremely high and did not have temporal correlation. In the other residential areas, the concentrations dropped quite a lot, but were still highly above the average contents of other counterpart cities in the world. The analysis of stable lead isotope ratios showed that lead isotopic composition in YangPu district varied much and changed randomly with time, while in Huangpu and PuTuo districts, the value of 207Pb/206Pb dropped significantly from 0.872±0.002 to 0.861±0.002. Combined with the data of lead contents and isotopic compositions of source-related samples, such as cements, coals, coal fly ashes, metallurgic dusts, oil combustion dusts, gasoline samples and soils, it was indicated that contribution from lead additives to airborne lead pollution in Shanghai was less than 30% in the time when leaded gasoline was used. However, stationary emission was always a dominant source in Shanghai, and the primary component of lead was believed to be contributed by the vast combustion of lead-containing coal emitted mainly by industrial activities all these years.