There are no strong indications that mixing FAME (Fatty Acid Methyl Ester) biodiesel up to 7 vol%2 and HVO (Hydrotreated Vegetable Oil) biodiesel up to 30 vol% will result in significant increase in harmful emissions by road traffic. This conclusion is based on the limited toxicological data suggesting low or negligible changes in the hazard profiles upon blending biodiesel.
The usage of biodiesel/petroleum diesel blends can be applied to achieve the Dutch targets for the use of renewable energy. However, the implications for human health due to changes in the composition of the engine exhaust is uncertain. To examine the potential impact of increasing the blend ratio of FAME and HVO biodiesel on human health, the engine emission associated toxicity has been examined by order of the Dutch Ministry of Infrastructure and the Environment. The assessment was based on literature of both measured harmful components as well as on toxicological studies.
Due to technical limitations of light duty vehicles with diesel particulate filter FAME biodiesel will most likely not exceed 7 vol%. The residual amount of biodiesel percentage up to 30 vol% will be HVO biodiesel.
Based on the limited available emission and toxicological data there are no strong arguments to expect a substantial increase of the toxicity of the exhaust using a blend of 7 vol% FAME biodiesel. Studies with HVO are very scarce. HVO blends up to 30 vol% are expected to produce a less toxic exhaust due to the structural similarities in the hydrocarbons and the higher purity compared to fossil fuel. This assumption needs to be confirmed by toxicological studies. Furthermore, the implications for the hazard of engine exhaust from vehicles at higher biodiesel blend percentages (>30 vol%) is at present not clear nor can a critical percentage be identified at which the toxicity of the exhaust reaches its maximum.
In addition, it is predicted that engine emissions will substantially decrease in upcoming years due to the latest emission legislation. Only a small percentage of the decrease will be the result of the replacement of petroleum diesel for biofuel blends. Altogether, the available evidence suggest that it is not likely that the amount of harmful emissions will increase substantially by blending low percentages of these two types of biodiesel, although this is surrounded by uncertainty due to a data gap.