Mohammad Rastgari - Deputy of Monitoring and Control of Tehran Province Environment Department.
Salar Ershadi - M.Sc. Energy Engineering, Expert and Monitoring Center Air Pollution in Tehran Province.

Air pollution caused by traffic, bad traffic situation and critical condition of shipping are two major issues in metropolises that have been emerged in recent years. Today, mobile sources of air pollution in the urban environment is the largest contributor in which programs and policies of the inspection and maintenance of vehicles cannot be separated from transport environmental issues. Tehran metropolis is the twenty-fifth most populous city, is reported inthe list of polluted metropolises in the world in recent decates. It seems that a major problem in the metropolitan transportation is the plans on road network conditions, equipment and road traffic management didn’t remain stable and have not developed enough in line with theimportance of car traffic and growing number of vehicles, and on the other hand, lack of an adequate public transport system and subway lines makes the problem more visible. This leads to traffic and road congestion at peak times in a metropolis like Tehran which has adirect impact on increasing air pollution in the city, especially at peak times of traffic which is between two thirty to four o’clock. Using lands without any plan and lack of convenienttransportation plans resulted in the centralization and concentration of industrial and commercial activities, schools, hospitals in Tehran which has added to the problem ofcongestion and increasing traffic in Tehran. The results of this study shows the reduced number of reference of vehicles to inspection centers in Tehran metropolis in recent years. Non-performance and strict implementation of rules relating to technical inspection centers,and illegally obtaining technical examination papers, the 5-year duration of the technical examination and lack of people welcoming are the causes of the problems and difficulties fortechnical inspection centers for light and heavy vehicles. Following the successful plans oftechnical inspection centers and public transportation in other countries in controlling air pollution will be discussed.

air pollution, inspection centers, the engine combustion, Tehran metropolis,comparative study