Mass balance for lead in the California South Coast Air Basin: an update.
A mass balance for lead for the year 1989 in the South Coast Air Basin has inputs to the atmosphere of 600 +/- 190 kg/day and outputs of 580 +/- 160 kg/day, showing rough agreement. Stationary sources are responsible for only about 5% of the total lead emissions. The bulk of the lead is emitted from vehicles using leaded gasoline (37%) and unleaded gasoline (15%), as well as from resuspension of previously deposited lead on roads (43%). Over half of the total emitted lead deposits on roads and nearby soil, while about one-third is carried out the basin by wind. A small amount, less than 10%, is deposited on surfaces throughout the basin. These percentages are approximately the same as those in a mass balance for the same region calculated for 1972, when lead emissions from leaded gasoline were about a factor of 70 greater than leaded gas emissions in 1989. When the lead emissions are used as inputs to a simple continuously stirred flow reactor model for the basin, reasonable agreement is obtained between calculated and measured concentrations.
Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
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Lankey
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Davidson
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McMichael
D000393:Air Pollutants / Q000032:analysis*; D002140:California; D005742:Gasoline / Q000032:analysis*; D006801:Humans; D007854:Lead / Q000032:analysis*; D008956:Models, Chemical; D001335:Vehicle Emissions / Q000032:analysis*; D014919:Wind
D000393:Air Pollutants; D005742:Gasoline; D001335:Vehicle Emissions; D007854:Lead