Lead in children's blood is mainly caused by coal-fired ash after phasing out of leaded gasoline in Shanghai.

Lead (Pb) is a highly toxic element to the human body. After phasing out of leaded gasoline we find that the blood lead level of children strongly correlates with the lead concentration in atmospheric particles, and the latter correlates with the coal consumption instead of leaded gasoline. Combined with the (207)Pb/(206)Pb ratio measurements, we find that the coal consumption fly ash is a dominate source of Pb exposure to children in Shanghai, rather than vehicle exhaust, metallurgic dust, paint dust, and drinking water. Those particles are absorbed to children's blood via breathing and digesting their deposition on ground by hand-to-mouth activities. Probably the same situation occurs in other large cities of developing countries where the structure of energy supply is mainly based on coal-combustion.

Characteristics of trace elements and lead isotope ratios in PM(2.5) from four sites in Shanghai.

PM(2.5) 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 PM(2.5) samples were determined. The annual average concentrations of PM(2.5) samples at each site were 84+/-30, 65+/-20, 55+/-18, and 41+/-10 microg m(-3), respectively, indicating there were severe air pollution levels in Shanghai. 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 PM(2.5) 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 PM(2.5) was very substantial in Shanghai.