Progress in Life Cycle Impact Assessment: Water Vapor Emissions and Respiratory Inorganics

Life cycle assessment (LCA) is being included formally in EcoDesign regulations. Especially product carbon footprint will be mandatory in Europe. However, life cycle impact assessment, including global warming potential (GWP) in LCA, is hampered by several challenges. One of these is a lack of water vapor characterization indexes for GWP. A life cycle inventory profile for air transport fuel, including water vapor emissions, is evaluated with state-of-the-art practice, i.e., Environmental Footprint (EF) Method and International Life Cycle Data (ILCD) 2011 Mid-point+, neglecting water vapor’s high altitude GWP compared to carbon dioxide. Then, the characterization factor in GWP over 100 years (GWP100) for water vapor and alternate normalization for particulates are introduced. The results are compared. The main findings are that the previous EF method and ILCD both generate rather realistic results for Particulate Matter and Respiratory Inorganics mid-point indicators, respectively, but the number of premature deaths should be better allocated to different specific emissions, and that water vapor may dominate the GWP100 result over the usual carbon dioxide. Respiratory inorganics may need one impact category, each starting with particles smaller than 2.5 µm. LCIA mid-points need measurable and understandable bases. The common knowledge of water vapor’s GWP100 should not be neglected in LCIA for air transport and beyond where relevant.