In this document, the final results of a Black Carbon measurement campaign on a single cylinder 4-stroke medium speed research engine are presented. The aim of the study was to analyse the impact of fuel oil quality on Black Carbon emissions. Furthermore, the composition of the particulate matter in the exhaust gas and a detailed fuel oil analysis of the VLSFOs are presented. The formation of Black Carbon is dominated by the aromatic content and H/C ratio of a fuel and could not be compensated by engine settings (injection timing or pressure). The aromatic fraction of investigated VLSFO fuels were dominated by harmful polycyclic aromatic hydrocarbons (PAH).