Ahmad Jonidi Jafari - Professor, Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences.,Tehran, Iran
Moftaba Ehsanifar - Ph.D. Student, Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences., Tehran, Iran
Housein Arfaeinia - Ph.D. Student, Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences., Tehran, Iran

Objectives: Investigating and determining the share of urbansources of air pollutants is an essential step in pollution controlmanagement. Studies indicate the main source of air pollution inTehran is the indiscriminate use of energy, while vehicles producemore than 85% of air pollution. Thus vehicles have the mostimportant role in Tehran’s air pollution.Methods: The present study investigated the share of differenttypes of vehicles in Tehran according to fuel consumption andemission factors and based onoutput data from the EMME/2software of Tehran Comprehensive Transportation and TrafficStudies in a morning peak hourin 2013.Results: The emissions of criteria pollutants (CO, HC, NOX, SOX,and P.M.) vary in different types of gasoline and diesel vehiclesaccording to emission factors, type and number of vehicles, fuelconsumption, and car mileage. Generally, in a traffic peak hour ina morning in 2013, the share of a variety of sedans, taxis,motorcycles, pickups, minibuses, public buses, trucks, and schoolbuses in pollutants emission was 48.36, 18.87, 16.02, 10.35, 1.50,2.49, 1.28, 1.13 percent, respectively.Conclusion:A trip by sedans or motorcycles emits 97 times anda trip by taxi emits 63 times as air pollutants as a trip by publicbuses. Therefore, raising public awareness about emissions ofcriteria air pollutants by vehicles for one trip or traverse of onekilometer in the city, and also encouraging them to manage theirtrips and make optimal use of private and public vehicles playimportant roles in reducing Tehran’s air pollution.

Criteria air pollutants, Emission factor, Vehicles, Tehran’s air pollution