AIR QUALITY DETERIORATION IN TEHRAN DUE TO MOTORCYCLES

Since there is a rise of motorcycles population as well as other motor vehicles, it seems that air Pollution deterioration should be studied as one of its environmental impacts. The main objective of this study was to develop a number of scenarios in order to determine the amount of Tehran's air pollution attributable to motorcycles and select the best and the most probable case to be recommended for implementation. The first step was to collect data such as the number of active motorcycles, daily traffic volume, average traveling speed and actual emission factors. For this purpose, a detailed questionnaire was designed to be completed by field surveys and measurements. The collected data were compared with traffic volume data, manufacturing statistics and the latest production capacity forecast in this field. Finally, with this data and emission factors for each type of motorcycle, an emissions inventory model was chosen to provide annual emissions from motorcycles in Tehran in different scenarios. The results showed that in 2002, there has been about 450'000 active motorcycles (4-stroke 58%, 2-stroke 28%, and moped 14%) with average speed of 40 km/h and average mileage of 110 km/d. Five scenarios were developed. The best scenario was "Changing all motorcycles to 4-strokes under EU-97 standard" which would result in reduction of NMVOC by 75%, CO by 35% and PM10 by 88%.