The study focuses on the effect of blending an oxygenated component (diglyme) and biodiesel fuel to conventional diesel. The basis of comparison was around the oxygen content of the blends paying significant attention to the most concerning emissions: nitrogen oxides and particulate matter. In assessing the potential of the two blends, the combustion and emission performances were analysed and directly compared. The addition of diglyme resulted in a combined reduction in NOX and PM emissions, which resulted in the control of the overall NOX/PM trade-off. The chosen component may provide the ideal compromise in terms of combustion efficiency and emission quality. However biodiesel still has a greater ability of enhancing the overall soot oxidation which can be seen as an important characteristic for diesel particulate filter regeneration. The substantial benefits displayed from the two blends demonstrate the effectiveness of oxygen availability in the fuel. (C) 2011 Elsevier Ltd. All rights reserved.