ISCST3 Tech Guide

Gaussian Plume Air Dispersion Model

7.3.2 Point and Volume Source Emissions

The seasonal deposition at the point located at a particular distance (r) and direction (2) with respect to the base of a stack or the center of a volume source for particulates in the nth particle size category is given by:


where the vertical term for deposition, Vdn, was defined in Section 1.3.2. K and D are described in Equations (1-1) and (1-63), respectively. QJ is the product of the total time during the lth season, of the seasonal emission rate Q for the ith wind-speed category, kth stability category. For example, if the emission rate is in grams per second and there are 92 days in the summer season (June, July, and August), QJ,l-3 is given by 7.95 x 106 Ql-3. It should be noted that the user need not vary the emission rate by season or by wind speed and stability. If an annual average emission rate is assumed, QJ is equal to 3.15 x 107 Q for a 365-day year. For a plume comprised of N particle size categories, the total seasonal deposition is obtained by summing Equation (2-7) over the N particle size categories. The program also sums the seasonal deposition values to obtain the annual deposition.