Closing Data Gaps with Emission Factors: A General Method Applied to EPDs in Brightway

Purpose Missing data are a fundamental challenge in Life Cycle Assessment (LCA). A promising way to address such gaps is the direct use of already calculated environmental impact assessments of upstream products. Although companies increasingly publish environmental information like Environmental Product Declarations (EPD), there is still limited research on integrating those emission factors directly as LCA results within standard LCA software to ensure seamless accessibility. Methods This paper presents a method to integrate aggregated emission factors from EPDs into LCI databases. The method combines reverse calculation with proxy selection, where proxies represent ecosphere flows. This enables the calculation of inventory results and the characterization of impacts in life cycle impact assessment (LCIA). The approach allows emission factors to be made available as LCA results within common LCA programs. Results and discussion The method is demonstrated by integrating the German ökobaudat (OBD) database – containing EPDs - into the open-source software Brightway. An example illustrates how conventional and EPD-based data can be used simultaneously to close data gaps in a user-friendly way. Conclusions The study shows that data lacking supply chain information can be incorporated into conventional LCA software. The proposed approach increases usability, as only one LCA modelling and calculation step is required , and it can be applied across different data sources and software environments.