To quantify accurately the adverse effects of the particulate matter (PM) fine fraction on climate, it is necessary to identify emission sources and associate them with aerosol radiative properties over long periods. Source apportionment is a useful tool to quantify PM contributions especially for organic aerosols (OA). Four years of real-time optical and chemical observations were combined to characterize OA sources and their absorbing properties at the ATOLL platform in Northern France. Positive Matrix Factorization (PMF) shows high contribution (74%) of oxygenated OA (OOA), followed by 14% of BBOA (due to biomass burning) and 12% of HOA (related to traffic) on average for the mass concentrations. Meanwhile, OA are responsible for 27% of light absorption at 370 nm, showing a significant contribution of Brown Carbon (BrC). A Multiple Linear Regression (MLR) analysis applied to determine source-specific Mass Absorption Efficiencies (MAE) of the OA factors highlights BBOA as the dominant source of BrC light absorption (64%).