Evaluation of modeled versus observed road traffic source apportionment and aerosol oxidation potential using the EMEP MSC-W model

The ability to induce oxidative stress has been suggested as a potential driver of the toxicity of
particulate matter (PM) exposure, being driven by aerosol composition and its relation to emission sources and chemical aging processes. PM originating from road traffic emissions has been especially implicated as being an important driver of aerosol oxidation potential (OP). In this work, road traffic PM simulated by the European Monitoring and Evaluation Programme (EMEP) Meteorological Synthesizing Centre – West (MSC-W) model is evaluated against source apportionment data across 19 sites in Europe. The source apportionment data includes information on both aerosol mass and source-specific OP of vehicular wear metals and primary and secondary vehicle exhaust organic aerosol, building upon the studies of Weber et al. (2021) and Daellenbach et al. (2020). Using the source-specific OP factors determined by the latter studies, the modeled contributions to OP are evaluated through comparisons with (OP) measurements for both the DTT and AA assays. We also briefly discuss the impact of model methodology, focusing on the choice of emission inventory, secondary organic aerosol formation scheme, and model resolution.