Document Type : Original Article
Department of Water, Wastewater and Environmental Engineering, Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran
Introduction: The study aims to select the optimal model to estimate the emissions from vehicles with
compressed natural gas (CNG) powertrain systems in Tehran to identify, evaluate and plan for controlling
emissions through CNG vehicles, and determining the pollution level of passenger cars produced by the Iranian
automotive industries and compare it with pollution standards.
Material and methods: In this study, locally-produced CNG vehicles' information was used to estimate the
pollutants emitted from domestic CNG vehicles using IVE and COPERT modeling software. Finally, the
modeling outputs were compared with the results of the ISQI emission test.
Result and discussion: Results showed that contrary to the initial assumption, supposing IVE software was
suitable for advancing the research objectives, the performance of IVE software was not reliable for CNG
vehicles, and the outputs of COPERT software were much closer to the values measured in the ISQI emission
test. The COPERT estimated values were more accurate by 65 and 78 percent for carbon monoxide and NOX,
respectively, but 13% worse for carbon dioxide.
Conclusion: Based on the findings, the COPERT model is more accurate than IVE for modeling CNG vehicles'
emissions, especially for CO and NOX. According to the findings, it is necessary to reconsider the superiority
and application of IVE software for determining the emission inventory and estimating the air pollutants
emitted from the CNG fleet in the country.
EPA., 2002. User’s Guide to MOBILE6.1 and MOBILE6.2: Mobile Source Emission Factor Model. U.S. Environmental Protection Agency. Available online at: https://www.epa.gov/.
EPA., 2005a. EPA’s National Inventory Model (NMIM), A Consolidated Emissions Modeling System for MOBILE6 and NONROAD. U.S. Environmental Protection Agency. Available online at: https://www.epa.gov/.
EPA., 2005b. User’s Guide for the Final NONROAD2005 Model. U.S. Environmental Protection Agency. Available online at: https://www.epa.gov/
EPA., 2015. MOVES2014a User Guide. US Environmental Protection Agency. Available online at: https://www.epa.gov/.
EPA., 2016. EPA Optimization Model for Reducing Emissions of Greenhouse Gases from Automobiles (OMEGA). U.S. Environmental Protection Agency. Available online at: https://www.epa.gov/.
Gkatzoflias, D., Kouridis, C., Ntziachristos, L. and Samaras, Z., 2006. COPERT 4: Computer programme to calculate emissions from road transport. European Environment Agency. 1, 1-70.
Huang, X., Wang, Y., Xing, Z., and Du, K., 2016. Emission factors of air pollutants from CNGgasoline bi-fuel vehicles: Part II. CO, HC and NOx. Science of The Total Environment. 565, 698-705.
ISSRC., 2008. IVE Model Users Manual Version 2.0 (Vol. 1). ISSRC. 3-47.
Napolitano, P., Alfè, M., Guido, C., Gargiulo, V., Fraioli, V., and Beatrice, C., 2020. Particle emissions from a HD SI gas engine fueled with LPG and CNG. Fuel. 269, 117439.
Planning and Budget Organization., 2020. Energy supply document of the transportation until 1420. Planning and Budget Organization. 2-7.
Pulkrabek, W. W., 1997. Engineering fundamentals of the internal combustion engine (Vol. 9). Upper Saddle River, N.J. : Prentice Hall, ©1997.
Rostami, F., 2018. Report of using energic oil products in 2018. N. I. O. P. D. Company. 9-10
Shafiepour, M., Alidoust, a., and Yeganeh, B., 2009. Explain national pollution standards for CNG cars in Iran 9th Transportation and Traffic Engineering Conference of Iran. 2-3.
Shafiepour, M., and Khamseie, B., 2008. Air Pollution Engineering (Vol. 1). In: Nashre shahr publication. 209-217.
Trivedy, R. K., Goel, P. K., 2010. An Introduction to Air Pollution. India: ABD Publishers. 5-10.
UTI., 2020. CNG vs. LPG vs. LNG Fuel: Understanding the Differences. available on https://www.uti.edu/blog/diesel/cng-lpg-lng-fuel
Wark, K., Warner, C. F., and Davis, W. T., 1998. Air Pollution: Its Origin and Control (Vol. 4). Addison-Wesley.
Zhang, H., 2018. Greenhouse gas Emission Model (GEM). Environmental Protection Agency. 2-15.