Site-dependent life-cycle analysis by the SAME approach: its concept usefulness, and application to the calculation of embodied impact intensity by means of an input-output analysis.

This paper describes a practical approach to site-dependent life-cycle analysis (SDLCA) that differentiates site-dependent environmental impacts from a system's processes by considering the geographical conditions of each process. This approach converts an environmental output into its impacts by using site-dependent characterization factors (SDCFs). This approach defines an area-the Spatial Area of iMpact Equivalency (SAME)-within the boundaries of the geographical system during site-dependent life-cycle inventory (SDLCI) analysis and calculates an environmental output from a process for the SAMEs. Each SAME represents a collection of geographical areas with internally homogeneous environmental impacts and can be mapped using a geographic information system. Preparing a SDLCI and SDCFs based on SAMEs facilitates the implementation of SDLCA by permitting the use of fewer regions during SDLCI. To demonstrate application of the SAME approach, an embodied impact intensity was formulated; it quantifies the impact directly and indirectly on the basis of the unit activity of a sector by means of input-output analysis with SDCFs. The validity of using SAMEs for SDLCA is demonstrated through two case studies: one studying suspended particulate matter, and one studying benzene. In both cases, the impact intensities are calculated using the SAME approach and the results are compared with those of site-generic LCI.