Carbonaceous aerosol accounts for an important part of the total aerosol mass and influences human health and climate through its effects on aerosol physical and chemical properties, yet the understanding of its atmospheric sources and removal processes is still incomplete. This study shows the state of the art of carbonaceous aerosol modeling in Europe by comparing simulations performed with seven chemistry and transport models (CTMs) currently used in Europe: CAMx, CHIMERE, CMAQ, EMEP / MSC-W, LOTOS -EUROS, MINNI and RCGC. The simulations were carried out under the EURODELTA III project and were evaluated against some intensive campaigns of the European Monitoring and Evaluation Program (EMEP) and the European Integrated Project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI).

Model simulations were performed over the same domain, using as much as possible the same input data and covering four seasons: summer (1-30 June 2006), winter (8 January – 4 February 4 2007), autumn (17 September – 15 October2008 ) and spring (25 February – 26 March 2009). Analyses of model performance in predicting elemental carbon (EC) for the four seasons and aerosol organic components (OA) in the last two seasons show that all models generally underestimate the measured concentrations. The maximum underestimation of Elemental Carbon concentration is about 60% and up to about 80% for total organic matter (TOM). The underestimation of TOM outside the highly polluted area is a consequence of an underestimation of secondary organic aerosol (SOA) and its main contributor in particular, biogenic secondary aerosol (BSOA). This result is independent of the SOA modelling approach used and the season. Daily concentrations and cycles of total primary organic matter (TPOM) are generally better reproduced by the models because they use the same anthropogenic emissions. However, the combination of emissions and model formulation led most models to overestimate TPOM concentrations in 2009.

None of the models was able to accurately reproduce daily SOA cycles at rural stations mainly because of the spatial resolution used in the simulations. For the carbonaceous aerosol compounds studied, the differences between the concentrations simulated by the different models are smaller than the differences between the concentrations simulated with one model for different seasons.