MASS-BALANCE BETWEEN EMISSION AND DEPOSITION OF AIRBORNE CONTAMINANTS

Quantification of (1) the total mass of airborne pollutants deposited around pollution emitters, (2) the contaminated radius around these po int sources, and (3) the proportion of emissions available for long-ra nge transport remains challenging for environmental scientists. Here, we present a simple method for comparing yearly airborne emission figu res from any point source with observed deposition estimates from the surrounding area. First,the deposition-distance function D(x) around t he smokestack must be defined. This requires the empirical determinati on of total (water soluble + particulate) annual deposition at several locations away from the source and of the extent of the smokestack '' shadow'' zone. Secondly, the loading function L(x) is obtained by inte grating D(x) around the point-source. This allows estimation of the ye arly mass of a contaminant deposited within an area corresponding to t hat of a circle of radius x around the point source. Thus, emission, d eposition, and (long-range) transport of airborne contaminants can be assessed quantitatively. Preliminary results from the Kola Peninsula, Russia, suggest that deposition of trace metals overwhelmingly occurs within 200 km from the source.