AERMOD Tech Guide

Gaussian Plume Air Dispersion Model

6.4.2 Buoyancy Induced Dispersion(BID) Component of Sigma & Sigmayz

For the CBL’s Direct & Indirect sources, Buoyancy Induced Dispersion (BID) is calculated following Weil

Equation (104)

The direct source plume rise is calculated from eq. (116).

For the Penetrated Source, BID is calculated as follows:

Equation (105)

The height of the penetrated source (hep) is calculated from eq. (119) in section 3.e.1).

For the Stable Source BID is calculated as follows:

Equation (106)

The stable plume rise ( hs ) is calculated from eq. (120).