Atmospheric Trace Elements And Their Application In Tracing Air Pollution

Atmospheric Trace Elements and Their Application in Tracing Air Pollution

The atmospheric trace element abundances associated with several major sources of air pollution in Western Oregon, such as the paper industry, the metallurgical processing industry, the plywood industry and agricultural field burning have been measured by instrumental neutron activation analysis (INAA). Air samples were collected directly from industrial stacks and during the field burning season using high volume air samplers, tape samplers and a cascade impactor. Nuclepore filter paper and Handiwrap were used as collection media for air particulates. The results show that some of the trace elements are highly correlated with a particular source of pollution, e. the high concentration of Zr, Hf, Ta, As, Cl, and Br associated with the metallurgical processing company; Na, Cl, Br, Cu, V, Co, Cr and Hg with the paper company; Na, K, Cl, Cr, Cu, Br and Hg with the plywood company and Ti, Na, Al, K, and Fe with agricultural field burning. Of all these characteristic elements, only Zr, Hf, Ta and As could be used as "natural occurring" tracers for tracing the dispersal pattern of stack effluent from a particular source. The concentrations of potentially toxic elements such as Hg, A.s, Se, and V emitted from these sources into the atmosphere were found to be too low to cause any health hazard in the area concerned. The atmospheric trace element abundances in Albany (an industrial area) and in Corvallis (a rural area) were also measured. Abnormally high trace element concentrations were found in the Albany area. Most of the trace element concentrations are highly correlated to the industries in the area. The rural air in Corvallis, on the other hand, shows very low trace element concentrations and may serve as an indication of the "continental background" contribution to atmospheric abundance. An artificial activable tracer technique using some of the rareearth elements (Dy, Sm, La, and Ce) was also developed to monitor stack effluent. These tracers were used in testing the generalized Gaussian plume model (Gifford, 1962) and Hewson's trapping plume model (Hewson, 1958) applied to describe the dispersal pattern of stack effluent in the Albany area. These models were found to work quite well under atmospheric stabilities types D, C, and B (Pasquill's classification, 1962) and not to work well under very turbulent conditions (atmospheric stability type A. or above). These meteorological models along with the techniques of multiple regression analysis were applied to predict the emission rates of the stack effluent involving multiple sources of air pollution in the Albany area. The artificial activable tracers were used as source tracers. It was found that these models, in general, can be applied to predict the emission rates withinafactor of two in multiple sources involving three stacks.

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