Movement patterns of prevailing winds flow and environmental impacts associated with the buildings and urban passage; The Case study Nahavand city in West Iran

From most important Climate challenges in the urban environment are strong winds and prevalent winds. The winds of change and movement in relation to roads، crossings and the urban sprawl as an environmental problem have been studied. One of the cities with considerable frequency in the strong winds in Iran West is Nahavand that has been studied as an example. Windrosees plotted for the period 1996 to 2005 represents that the most frequent winds occur frow West direction and has been the strongest winds in March. Chief streets has locate parallel to movement of prevalent wind. This problem causes strengthen wind flow within the city. In this city descriptive two patterns of wind effect have formed that one is street parallel to prevalent wind and other is urban narrow passages between two rows from buildings with vertical angle. in both of case wind flow was transferred with the pressure and high speed of the. The wanted effect of wind in the city have been reducing air pollution and its adverse effects، the sidewalks and traffic disturbance، soil particles conveyance into the city، breaking branches and create coldwind in March.