摘要
The aim of this work is the assessment of the behavior of the radiation over studied area at the different seasons of the year using mathematical model. To achieve this purpose, the dispersion factor has been calculated. The calculated dispersion factor gives an indication about the behavior and the distribution of pollutants in the atmosphere. Since the used model requires specific measuring hourly metrological data over long periods of time at least one year such as wind speed, incoming solar, radiation and wind direction for studied area. Also terrain information and population distribution should be taken into consideration. The atmospheric parameters such as monthly wind rose, hourly stability classes and joint frequency have been determined using developed computer programs. The results of wind rose shown that the prevailing wind direction for studied area is northeast direction in winter. This situation give us a primary knowledge about months （months of winter） at which the studied area may be affected by the air coming from the east borders. The results of dispersion factor indicate that the sectors S, SSE and SE for the studying area are greatly exposed to air which may be polluted.
