Evolution of Inspection and Maintenance Program, A Way to Control Air Pollution Emission From Passenger Cars in The City of Tehran

a variety of studies highlight the contribution of mobile sources in air pollution emissions in the city of Tehran. among various mobile sources, passenger cars are of high importance due to their population and activity. while production level standards regarding emissions are important, the role of periodic inspection and maintenance programs is undeniable in stabilizing the emission performance of vehicles during their lifespan. the inspection and maintenance program in Iran is simple. it is unloaded, and has no control over the performance of catalytic converter and NOx emissions. consequently, it is suggested to implement a more strength inspection and maintenance program called "Improved Inspection and Maintenance" in the city of Tehranwhich is loaded, has more strength emission limits, and includes tests regarding the performance of catalytic converter and NOx emissions. also, it uses the OBD data. this Improved Inspection and Maintenance could be the permission for the vehicles to enter specific parts of the city of Tehran. or, it could be the permission for vehicles to traffic in unhealthy days. the Improved Inspection and Maintenance could replace the current inspection and maintenance program gradually in Tehran. then, vehicles entering Tehran without Improved Inspection and Maintenance could be fined.