Numerical simulation of global ultrafine particle (UFP; particulate matter with diameter < 0.1 um) concentrations with the ECHAM/MESSy Atmospheric Chemistry model (EMAC) for the year 2015. The simulations are available at two different horizontal resolutions: model resolution (1.875°x1.875°) and downscaled using emission databases as proxies (0.1°x0.1°). Additionally, the UFP concentrations at model resolution are size segregated (1.7-20 nm, 20-50 nm, 50-100 nm).