Conditions controlling atmospheric pollutant deposition via snowpack

Abstract

Solid precipitation represents a potentially important addition to other measures of deposition. However, an accurate estimate of snowfall amount and pollutant loading is not a trivial matter. There are obvious distinctions between regular precipitation collection and snowpack sampling that represent the cumulative chemistry of bulk deposition. The main goal is to show the most important processes and factors that may influence the rate and magnitude of pollutants deposition affected by the snowfall and snow cover: atmospheric pollutant enhancement of snowfall, pollutants deposition at snow cover surface, drifting and blowing snow, formation of the snow cover and its internal changes, as well as pollutants flow through the snowpack. These phenomena lead to continuous changes in the chemistry of the snow cover and the deposition calculated on the basis of pollutants concentrations in daily portions of atmospheric precipitation. The real deposition released from snowpack is strictly related to the number and depth of thaw episodes. If the amount of stored pollutants is large, first portions of ablation water flushing from the snowpack can carry the load of pollutants, and potentially affecting the environment in a detrimental way. Igneous bedrock is especially sensitive to acidic ions because of its low buffering capacity.