Sensitivity Analysis of Hazardous Air Pollutants Emission from Passenger Cars to Traffic, Geographic and Environmental Parameters (Case Study: Tehran)

This study was conducted to determine the effects of various traffic, geographic, and environmental parameters on the vehicular emissions of HAPs (Hazardous Air Pollutants). In this case study, an arithmetic sequence was defined in the range of inputs to enter discrete independent variables into the IVE (International Vehicle Emissions) model. After simulating the results by the IVE model, a linear regression model was used to determine the sensitivity of the exhaust pipe HAPs emissions to the input parameters. The findings of the present study indicated that the passenger car fleet age is the most effective parameter on the emissions of 1,3-Butadiene, Acetaldehyde, and Formaldehyde with R2 (Coefficient of Determination) of 0.71, 0.68, and 0.66. In addition, this analytical study proved that the most important and effective parameters in increasing the emissions of Ammonia and Benzene are road gradient and the amount of benzene in the fuel with R2 of 0.90 and 1.00, respectively. According to the present research findings, by analyzing the changes in the emission rate of pollutants under the influence of different values of traffic, geographic, and environmental parameters, the optimum values of each of these parameters can be evaluated to minimize the vehicular emission rate. In conclusion, renovating the fleet of passenger cars, improving fuel quality, and building roads with a gentle slope should be considered as the solutions to reduce the emissions of HAPs in Tehran.