Three-Way Framework for Evaluating Regional Localization Effects in Remediation Footprint Tools

Résumé fourni par la source

Environmental footprint assessment is increasingly used to characterize the secondary impacts of contaminated site remediation. However, many established green and sustainable remediation tools rely on U.S.-based emission inventories and background data, raising questions about how their estimates change when applied under other regional conditions. This study proposes a three-way evaluation framework that examines Sitewise™ and SEFA outputs alongside a Sitewise-informed China-localized recalculation using domestic emission factors. The framework was applied to an excavation-and-transport brownfield remediation project in northern China using five indicators: greenhouse gas emissions (GHG), energy use, NOx, SOx, and particulate matter. In this case, Sitewise™ and SEFA produced numerically similar GHG estimates and moderately different energy estimates, with pairwise differences of 7% and 27%, respectively. Under the assumptions of this case, their GHG estimates were 26% and 20% lower, respectively, than the localized recalculation. A screening counterfactual using a common U.S. reference grid factor indicated that grid factor substitution accounted for 19.2% of the Sitewise-to-localized numerical difference and 24.5% of the SEFA-to-localized numerical difference. Air pollutant results showed stronger pathway dependence: NOx estimates differed by up to approximately eightfold, and the localized result fell between the two tool estimates under the stated assumptions. Within the tested epistemic ranges, the localized GHG result remained above both fixed tool outputs, the NOx result remained between them, and the SOx result remained below both in every draw; the baseline PM relationship was retained in 92.7% of draws, while localized energy equaled the Sitewise™ result by construction. Across the native tool runs and a transparent localized transport linkage screen, a 25% reduction in haul distance was associated with a 12.5–22% reduction in total GHG estimates. The comparison harmonized the remediation program and comparison unit, but not the complete background life cycle boundary; the results therefore represent defined-boundary pathway estimates rather than fully boundary-harmonized LCA results. Because the localized pathway retains the Sitewise-derived fuel–energy balance and activity category shares, it is interpreted as a case-specific factor localization recalculation rather than an independently documented project inventory or external comparison standard. The observed directional differences characterize the present case and tested assumptions and do not support a general judgment about the relative performance of the tools. The framework may be adaptable to other jurisdictions, but its transferability should be evaluated using additional sites, remediation technologies, and independently documented activity inventories.

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