Source-receptor reconciliation of routine air monitoring data for trace metals: an emission inventory assisted approach

Inventory procedures for fine-particle trace-metals emissions are developed that assist aerosol source apportionment by receptor modeling techniques. It is shown how sparse routine air monitoring data sets on a very few trace elements can be used in chemical element balance calculations once emission inventory data have shown that a very few source signatures do complete a mass balance on those chemical elements that were measured. Methods developed are tested in the South Coast Air Basin of California for the year 1976, where it is shown that over 80% of the fine lead emissions comes from highway traffic, 81% of the nickel arises from fuel oil fly ash, and more than 90% of the iron and manganese comes from soil-like materials. With use of readily available trace element data from local and Federal monitoring networks, it is found that most monitoring sites are exposed to aerosol containing about 20% highway vehicle exhaust, 1-2% fuel oil fly ash, 20-50% soil dust or road dust, with sulfates and nitrates each present at about 15% of total mass.