PMCAMx-2008, a detailed three-dimensional chemical transport model, was applied for the first time in Europe to simulate fine organic aerosol concentrations during the months of May 2008, February 2009, July 2009 and January 2010. The model includes a state-of-the-art organic aerosol module which is based on the volatility basis set framework treating both primary and secondary organic components as semivolatile and photochemically reactive. The model predicts that fresh primary OA (POA) is a small contributor to organic PM concentrations in Europe during the summer and spring, and that oxygenated species (oxidized primary and biogenic secondary) dominate the ambient OA. During the winter model results suggest a significant underestimation of OA emissions from wood burning. Use of very high resolution emissions inventory does not result in a significant improvement of the predictions of the model over the Megacity of Paris.