Numerical Simulation of Air Pollutants in Tehran, Based on Wind Patterns By TAPM

Through this article, the distribution of air pollutants in Tehran have been simulated based on wind patterns with and without the presence of synoptic by TAPM (a meso-scale model). The simulation covers three horizontal resolution domains 30, 15 and 5 kilometers. The pollutants chosen for this are CO and PM10 and wind data is 10 meter height level. The result has shown that the model simulated the wind direction with an index of agreement 90 percent, the wind speed with 60 percent and the emission about 51 percent. This can be acceptable, because the station measures the pollution based on point sources while the model does simulation in the surface level.The statistical result also has shown that concentration of pollutants increases from north to south and east to west. The variance analysis shows that two city zones (11, 12) are the most polluted areas and the zone 21 is the cleanest one. This is due to the wind direction ruling in Tehran. With the presence of synoptic conditions, the wind speed increases in height level and the contours show harmony while in conditions without the presence of synoptic, the wind speed decreases and the contours do not show any harmony. Since the wind speed is almost always less than the Tu. Coefficient, it is not expected that the wind refine the air in Tehran.