ISCST3 Tech Guide

Gaussian Plume Air Dispersion Model

6.3 The ISC Short-term Dry Deposition Model

This section describes the ISC Short Term dry deposition model, which is used to calculate the amount of material deposited (i.e., the deposition flux, Fd) at the surface from a particle plume through dry deposition processes.

The Short Term dry deposition model is based on a dry deposition algorithm (Pleim et al., 1984) contained in the Acid Deposition and Oxidant Model (ADOM). This algorithm was selected as a result of an independent model evaluation study (EPA, 1994).

The deposition flux, Fd, is calculated as the product of the concentration, Pd, and a deposition velocity, vd, computed at a reference height zd:


The concentration value, Pd, used in Equation (1-79) is calculated according to Equation (1-1) with deposition effects accounted for in the vertical term as described in Section The calculation of deposition velocities is described below.