Effects of Reducing Lead in Gasoline:  An Analysis of the International Experience

To assess the relations between use of lead in gasoline (GPb) and population blood lead levels (BPb), we examined 19 studies from six continents. In 17 of the studies, there are data on changes in BPb before and after changes in use of lead in gasoline. In 11 of the studies, there are data on air lead levels (APb). For a given location, there is a strong linear correlation between BPb and GPb, with a median correlation coefficient of 0.94. Across locations for a given GPb, BPb is positively correlated with city population. As GPb is reduced to zero, blood lead levels across locations converge to a median of 3 μg/dL. This convergence of BPb levels occurs at different times for different locations and corresponds to the timing of gasoline lead reductions. For those locations with available air lead data, air lead concentrations converge to ≤0.2 μg/m³ as GPb is reduced to zero. Together, these features indicate that reductions in gasoline lead levels have been a major causal factor in the observed reductions in population blood lead levels at these locations and show that BPb levels of about 3 μg/dL are widely achievable.