Simulation of Dispersion of Polluted Gases in Atmosphere

A computer program was developed to predict the dispersion of gas pollutant in the atmosphere. This program relies on puff method, and in order to consider the wind shear effects, the program has the ability to consider the complete dynamic and unsteady atmospheric conditions. Plume rise of hot pollutants due to buoyancy effects was also considered. The program has the capacity to perform the realtime calculations and uses on-line data of atmospheric conditions that are measured by an anemometer and a thermometer. In order to consider the effects of presence of building and other obstacles or sudden change in surface roughness on dispersion of released materials, a model was added to evaluate the dispersion coefficients in the wake of obstacles. Using this relatively complete simulation, we analyzed the effects of above parameters on the dispersion of gas pollutants in atmosphere and the interpretation of the results is presented.