In the present work, a computer program has been constructed for investigating the factors affecting the dispersion of stack emissions. These factors are wind speed, wind direction with respect to source, wind direction with respect to receptor, ambient air temperature and atmospheric stability conditions. Shobra Elkhema Power Plant (SEPP), which has four stacks, was selected as a real case to study the effect of the above mentioned factors on the dispersion of all stacks emissions in the air. The results indicate that the effect wind speed on total concentration, from the four stacks, is directly proportional to the increase of wind speed, while the distance of maximum concentration is inversely proportional to it. Also it is found that the total concentration is inversely proportional to the increase of wind angle direction with respect to receptor, while the distance of maximum concentration is shifted towards the source location. Total concentration is directly proportional to the increase of ambient air temperature, while the distance at which the maximum concentration occurs is almost constant. With regards to atmospheric stability conditions.