Air pollution,particularly in winters, becomes a crucial problem inlarger cities of Iran; each winter more and more days,daily activitiesare halted by the governor to reduce the share of cars in increasing the pollution to conditions dangerous for health.Rain fall has dropped significantly in recent years, both in total volume and in the frequency. Stable weather conditions and inversion leave dark and polluted cities. The only action to activate any balancing cycle is to wait for wind and rain. Such conditions, if continued by some days, cause severe health and social crises. This thesis means to provide a SD model to understand better the problem, and evaluate policies which may reduce the strength of the crisis.
