Atmospheric LeadA Success Story

The Natural State

• Soil dust aerosols derived from rock weathering• 0.010 ± 0.002 mg//year with some variation caused by changes in source• For example: During the Younger Dryas (YD), background rates increased by a

factor of 35

The Unnatural StateLead in Air• Petrol• Industrial Processes• Soil tillage and enhanced rates of

soil erosion, thereby promoting the creation and release of soil dust

• Lead Mining

By 1979, the lead flux had reached 15.7 mg//year, exceeding the natural flux by a factor of more than 1500

Pb EF (Pb levels normalized to Sc levels)

Historic Lead Ratios (206Pb/207Pb)