TRACI Assessment of Transportation Manufacturing Nexus in the U.S.: A Supply Chain-linked Cradle-to-Gate LCA

Abstract

Sustainable transportation is an inevitable component of sustainable development intitiatives for mitigating the climate change impacts and stabilizing the rising carbon emissions thus global temperature. In this context, comprehensive analysis of the environmental impact of transportation can play a critical role towards quantifying the midpoint environmental and human health related impacts associated with the transportation activities triggered by manufacturing sectors. This study traces the life cycle impact of the U.S. transportation and manufacturing sectors’ nexus using Tool for the Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) in the context of the Economic Input-Output Life Cycle Assessment (EIO-LCA) framework considering the following midpoint impact categories: ‘global warming’, ‘particulate matter’, ‘eutrophication’, ‘acidification’, and ‘smog air’. Both direct (onsite) and indirect (supply chain) industries’ relationships with transportation industry are considered as the main scope. Results indicated that top ten contributor manufacturing sectors accounted for over 55% total environmental impacts on each impact category. Additionally, based on the decomposition analysis, food manufacturing sector was found to be the major contributor to smog air with an approximate share of 21% in the entire supply chain. Automobile related manufacturing sectors also have significant impact on all five life cycle impact categories that the environmental impact of transportation is higher than on-site (direct) impact. Overall decomposition analysis of 53 manufacturing sector indicated that the environmental impact of transportation has severe effects on ‘smog air’, ‘eutrophication’ and ‘acidification’ with a share of 16.4%, 10.5%, and 6.0%, respectively. When we consider the average percentage share of transportation related environmental impact on the entire supply chain, U.S manufacturing sectors have a negative impact with a share of 18.8% of ‘smog air’, 16.8% for ‘eutrophication’, and 8.1% for ‘acidification’.