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Frequently Asked Questions - How to use the USEtox model

The official USEtox model documentation can be found on this website under Model Documentation.

The official version of USEtox does not include particulate matter (PM) at the moment. Other atmospheric chemical fate models can better describe the fate of particulate matter in the air, including the formation of secondary particles from NH3, NOX, and SO2 emissions. The International Reference Life Cycle Data System (ILCD) Handbook recommends using the characterization factors computed in Humbert (2009). These characterization factors have their intake fractions based on an adaptation of USEtox for primary PM and CO, Greco et al. (2007) for secondary PM from SO2 and NOx, Van Zelm et al. (2008) for secondary PM from NH3 and RiskPoll (Spadaro and Rabl 2004) to differentiate among high-stack, low-stack, and ground-level emissions of primary PM for urban and rural conditions, respectively, and their effect factors based on a combination of Van Zelm et al. (2008), Kuenzli et al. (2000), and Hofstetter et al. (1998).

The current version of USEtox only models impacts in the freshwater environment. The reason only freshwater impacts are investigated is that mainly toxicity tests on freshwater species are available.

The damage matrix links the number of incidences (i.e. cancer or non-cancer cases) to the potential consequences of a chronic toxicological effect. It accounts for severity of the diseases/incidents considered. As there is a high uncertainty related to the severity and a lack of evidence for significant differences when combining dose-response slope and severity of disability, the damage matrix and differences between cancer and non-cancer have been left out in the current version of the USEtox model.