The effect of increasing the height of the buildings on air quality Case Study: Urban residential block in the center of the Esfahan city

According to the increase of urban population cities are going to be high rise and compact. Meanwhile because of the presence of a large number of factories and some refineries near the city and also its’ heavy traffic it has become one of the most polluted cities in Iran. Refer to statistics from Isfahan Meteorology center in the year of 1392 this city had 67 day with unhealthy Weather that most of this state occurred in the winter because of inversion phenomenon. In this research the effect of high rise construction and changes in the elevation of buildings in an urban block located in the center of Isfahan in 15 years ago, now and 15 years later has been evaluated by ENVI-MET software. During the winters the effects of buildings evaluation’s rise on the temperature of urban block, wind velocity in the horizontal state (pedestrian level) and the vertical movement factor has been investigated. The results show that in the winter due to the elevation increase the temperature of urban block decreases by 0.025 °C also the horizontal wind velocity (pedestrian level) increases by 0.2 m/s that is unpleasant. Meanwhile the vertical movement factor in the winters decreases due to rise in elevation. This changes in the temperature, wind velocity near the ground level and the movement factor in the winter cause increase of inversion occurrence in this urban block so air at near of the ground level.