EVALUATION OF EMISSION INVENTORY OF AIR POLLUTANTS FROM RAILROAD an‎d AIR TRANSPORTATION IN ISFAHAN METROPOLITAN IN 2016

Introduction: For many years, the historical city of Isfahan in the center of Iran has been faced with heavy transportation traffic. This heavy transportation is introducing large amounts of air pollutants into the city, causing many risks to human health, environment, etc. This study evaluates the fuel-based emission inventory of NOx, SOx, HCs and CO released into the atmosphere of Isfahan by both trains and airplanes. In addition, the emission inventory of PM10, PM2.5 and volatile organic compounds were investigated for Isfahan trains. Materials and methods: The validated methods of the United States Environmental Protection Agency and the European Environmental Agency have been utilized to estimate the emission inventories of trains and airplanes in Isfahan metropolitan. Both methods are based on average emission factors. Results: The results in 2016 show that, an average of 13,297 tons NOx, 0.13 tons SOx, 691 tons HC, 727 tons VOCs, 329 tons PM10, 319 tons PM2.5 and 1374 tons CO were released into the atmosphere of Isfahan metropolitan by trains every year. Investigations of the airplane emission inventory show that in 2016, an average of 8,076 tons CO2, 3.8 tons HC, 19.4 NOx, 22.8 tons CO and 2.54 tons SOx are released annually into the atmosphere by airplanes in Isfahan metropolitan. Conclusions: It is concluded that the most important pollutants emitted from railroad systems in Isfahan are nitrogen oxides. Sepahan-Shar suburb, in the southern part of Isfahan, receives the majority of generated pollutants by passing trains. At the present time aircraft are not an effective sources of pollutants in Isfahan.