Size-separated aerosol chemical characterization over Ny-Ålesund during the Arctic summer of 2010

•Mass-size distributions of Arctic aerosols show tri-modal with nucleation-, fine- and coarse-modes.•Mass concentration of coarse-mode particles dominates that of fine-mode.•Combined marine and BC aerosols contribute (> 65%) to the total aerosols.•Greater aerosol radiative forcing is due to BC aerosols.•Air mass trajectories reveal mixture of marine and continental pollutants contribute more at higher altitudes while marine particles at lower altitudes.