Characterization of atmospheric pollution by means of stochastic indicator parameters

Deriving indicator parameters for determining regions at risk and reducing uncertainties is an important part of atmospheric pollution characterization. In this paper we introduce regional indicator parameters that characterize contamination levels by means of stochastic analysis. The expressions obtained are general, and can be used for different types and distributions of pollutant concentrations. We calculate indicator parameters that represent excess contamination above a threshold level specified by the environmental standards, and we study certain scaling properties of the level-crossing contours. Regional indicator parameters are expressed in terms of the pollutant probability distribution, and are calculated explicitly for specific cases. Certain properties of the indicator parameters related to scale effects are also discussed. An application involving a sulfate deposition data set is discussed, which provides valuable insight regarding stochastic indicator parameters and their importance in environmental policy and decision making.