Lead in the atmosphere has decreased significantly since the 1970s primarily due to:

Question

Quizplus · Accepted Answer

The phasing out of leaded gasoline and replacing it with unleaded gasoline has been the primary reason for the decrease in lead in the atmosphere since the 1970s. Leaded gasoline was a significant source of lead emissions, and its replacement has led to significant improvements in air quality. The other options may have contributed, but the most significant factor was the switch to unleaded gasoline.

Lead in the Atmosphere Has Decreased Significantly Since the 1970s