Amir Ghahremanlou - PhD Candidate, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Mahmoud Saffarzadeh - Professor, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran.
Ali Naderan - Assistant Professor, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Hassan Javanshir - Assistant Professor, Department of Industrial Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran.

Transportation and land use are the two major sectors that contribute the most to the spread of environmental pollution. Transportation through accessbility affects land use while land use through the production and attraction of trip affects transportation. The purpose of this study is to investigate the accessibility of ۲۲ districts of Tehran metropolis, how the city develops and their impact on increasing air pollution. This is an applied research where the data and information used in this research were obtained from Tehran Municipality and Statistics Center of Iran and for their classification and analysis, depending on the need, SPSS, Arc GIS and Google Earth software have been used. The results of Pearson correlation show that about ۲۴% of land uses in Tehran have a significant relationship, which indicates a high separation between types of land uses and ultimately the scattered growth of Tehran. By analyzing and calculating the accessbilities, it was found that ۳۸% of the internal communications between the districts are at the level of good and very good accessbility, ۳۲% have the average level of accessbility and ۳۰% are at the level of poor and very poor. The average route factor of Tehran is estimated to be ۱.۵۲, which indicates that Tehran is classfied in the average level of accessbility. Another finding of this study is the effect of land uses and accessbility levels on increasing air pollution in Tehran which is important to urban planners and policy makers.

land use, Transportation, Air pollution, Tehran Metropolis