Abstract:
Computer simulations of passive gas dispersion can be used to predict the dispersal of a
toxic air pollutant in to the atmosphere. These predictions play a significant role in the
disaster management and in rescue activities. Most of the chemical warfare agents are
considered as dense gasses or liquids due to their physical properties and storage
conditions. However, the dispersal of released gas or vapor clouds is often modeled by
passive gas simulations (Kingdon, 2007). Such a model is capable of graphically
representing the dispersion which allows calculating the concentration of the toxic gas in
any location at a given time. Moreover, it can predict the number of human lives at stake.
The dispersal of a passive gas in the atmosphere mainly depends on the type of release,
meteorological conditions, geographical parameters and chemical and physical processes.
In considering the toxicity of an air pollutant in the atmosphere, it is important to focus on
chemical reactions. Particularly, it is straightforward to introduce first order chemical
reactions into dispersion models as a reduction or an increment of the effective mass of
the toxic pollutant.
