Several studies have reached the same conclusion on theimportance of non-exhaust emissions. Rexeis and Hausberger(2009) predicted that the percentage of non-exhaust PM of thetotal PM emissions will increase from 50% in 2000 up to 80e90% by2020. Jorß and Handke (2007) € modelled non-exhaust emissions ofPM2.5 in Germany and found that non-exhaust sources accountedfor 25% of traffic PM2.5 emissions in 2000 and are expected tocontribute 70% of traffic PM2.5 by 2020. This conclusion was alsoreached by Denier van der Gon et al. (2013), who predicted nonexhaust will likely be the dominant source of total PM emissionsfrom traffic by 2020.