Abstract

Urban public transportation sector in general is heavily dependent on fossil - oriented fuels, e.g., diesel. Given the fact that a major proportion of urban pollution and the consequent threats towards public health are attributed to this sector, serious efforts at both technical and political levels have been being made to introduce less-polluting fueling regimes, e.g., partial replacement of diesel with biodiesel. In line with that, the present study was aimed at evaluating the emissions attributed to 5 blends of waste cooking oil (WCO) and poultry fat (PF) biodiesel fuels (i.e., B5-WCO and B5-PF fuel blends) when used in urban buses during idle operation mode. Moreover, the attributional and consequential environmental impacts of using these fuel blends were also investigated through a well to wheel life cycle assessment (LCA) by considering the real-world condition combustion data using ten urban buses. The findings of the ALCA revealed that the application of 1 L B5-WCO fuel blend could potentially reduce the environmental burdens in human health, ecosystem quality, and resources damage categories compared with using the B5-PF fuel blend. The situation was opposite for climate change damage category in which using 1 L B5-PF fuel blend had a lower impact on the environment. Overall, the environmental hotspots in the B5-WCO and B5-PF life cycles were identified as the combustion stage as well as the diesel production and transportation. From the consequential perspective, using 1 L B5-WCO fuel blend could potentially decrease the environmental burdens in human health, ecosystem quality, and resources damage categories. While, the situation was different for climate change damage category where using 1 L B5-PF fuel blend could have a lower impact on the environment. In conclusion, using B5-WCO fuel blend as an alternative for diesel could be an environmentally-friendly decision for the Iranian urban transportation sector at the policy level as long as the marginal suppliers of oil would be the same as the countries considered herein, i.e., Malaysia and Argentina. (C) 2017 BRTeam. All rights reserved.