Diffusion Models for Transient Releases

Abstract

Plume models were developed to predict the concentration due to a nonbuoyant release from a source whose strength decreases exponentially with time of a pollutant that reacts in the atmosphere at a first-order rate. Models were developed that combined the conventional Gaussian plume with one of three different one-dimensional models to describe advection and dispersion in the downwind direction: advection without downwind dispersion, advection and dispersion by a Fickian puff, and advection and dispersion by a puff of constant size. In addition to these one-dimensional dispersion models, a model based on three-dimensional Fickian pulls was also developed.