Adding spatially-resolved characterization factors for ozone formation potential in the United States Environmental Protection Agency's tool for the reduction of chemical and other impacts

Tropospheric ozone is included in life cycle impact assessment because it continues to be a concern for human health, vegetation, and infrastructure. Current trends in impact assessment modeling include adding spatial resolution to better understand how impacts vary across product life cycles that are typically global in nature. The United States Environmental Protection Agency's Tool for the Reduction of Chemical and other Impacts (TRACI) has previously provided national average characterization factors for ozone impacts in North America. This work focuses on updating the ozone formation model in TRACI by developing characterization factors at midpoint level based on urban archetypes that can provide spatial resolution during life cycle assessment and expand coverage globally. The Statewide Air Pollution Research Center (SAPRC) box model is used to calculate maximum incremental reactivity (MIR) for 1008 volatile organic compounds in the 219 archetypes defined for urban geographies. Median MIR values for US cities are within 25% of previous work. Aggregated characterization factors are also derived for countries around the world to accommodate life cycle assessments where geographic resolution is preferred at the country-level. Caveats and points to consider when interpreting ozone formation impact data are included to highlight the caution that must be exercised when including this impact category in a study.