Surface melt in the ablation zone is dominated by atmospheric temperature and surface albedo. We developed a surface mass-balance model with a dynamic component of glacier ice albedo which includes surface properties, clouds and the angle of the sun. The ice albedo reduction is mainly caused by impurity accumulation of non-biological origin such as dust and black carbon (BC), which is currently not included in other surface mass-balance models. Simulations show that dust from meltout is the main source of impurity mass at the melting glacier ice surface, and current rates of atmospheric deposition of dust play only a minor role. However, for BC the atmospheric deposition is the main source where ice melt rates are below 1 m, and atmospheric deposition is most likely from intercontinental transport due to the scarce population and lack of forests in Greenland.