The following appears in a box on
page 48 of the printed report.
Evaluating Results: Reducing the Use of
Leaded Gasoline
One of
best documented evaluations of the impact of a risk management
action on pollutant emission levels concerns leaded gasoline. The
burning of gasoline was the single largest source (90%) of lead
in the atmosphere beginning in the 1920s. Significantly less of
the lead monitored in the air today comes from gasoline because
EPA phased out the use of lead in gasoline. In 1984, the average
lead content of gasoline was 0.44 grams per gallon; in 1991-1992,
it was less than 0.0003 grams per gallon. EPA estimated that
before the regulations to control lead in gasoline were in place,
the total amount of lead released to the air from motor vehicles
was about 95 metric tons in 1979. After the controls were in
place, only 2 metric tons were emitted from motor vehicles in
1989, with less than 35% of the lead in air attributable to
gasoline. Today, the emission of lead from motor vehicles should
be nearly zero, as required by the 1990 Clean Air Act.