Response of atmospheric lead to decreased use of lead in gasoline

Wet-only precipitation collected in urban and rural sites in Minnesota have been monitored for lead since the late 1970s. Annual volume-weighted mean concentrations of Pb in precipitation have decreased from 29 to 4.3 mg/l at the urban site and from 5.7 to 1.5 mg/l at the rural station during 1979-83. Annual Pb fluxes in precipitation have decreased during this period: from 2000 to 370 ng/sq cm at the urban site and from 430 to 100 ng/sq cm at the rural site. The decreases in atmospheric Pb fluxes are closely correlated with decreases in Pb used in gasoline in Minnesota and nationally.