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A computer program was developed to predict the dispersion of gaseous 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 ability to perform the real-time
calculations and uses on-line data of atmospheric conditions that are measured
directly. In order to consider the effects of the presence of buildings and other
obstacles or sudden changes in surface roughness by the 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 the
above parameters on the dispersion of gaseous pollutants in the atmosphere.