The differences between the Swedish MK1 diesel and European diesel have remarkably been reduced and both have low content of sulphur and aromatics. There are, however, still differences, both in the specifications and in the real content in available diesel fuel. This literature study summarizes facts and lack of facts on differences in emission from MK1 and sulphur free EN590:2009. Only a few studies compare different modern diesel qualities. The studies found cover engines of the following categories: Off road engines Stage I Light vehicles, Euro 3 Heavy Duty engines, Euro III, Euro IV, Euro V. For many of these engine categories there is only little information of unregulated emissions. Only one Euro V engine is tested and only for regulated emissions.