Lead in the ambient air and blood of children in Helsinki.

Lead concentrations have been measured in the ambient air of Helsinki since 1978. The mean air concentrations at various stations reached maximum values in 1980 of 333-1150 ng/m3. From 1980 to 1996 the concentrations decreased to one-hundredth, from 745 to 7 ng/m3, at the two centrally situated stations where measurements were made continuously. Concomitantly, the estimated annual emissions of lead in Helsinki decreased from 78 tons to < 1 ton, mainly owing to the cessation of lead emissions in exhaust gases from road traffic. The reduction in lead levels in the ambient air has been reflected by the lead levels in the blood of children in a centrally situated day-care centre. The mean concentration of lead in the blood of children in the day-care centre was 46 micrograms/l in 1983, 30 micrograms/l in 1988 and 26 micrograms/l in 1996.