Biofuels were all the rage in the 1990s, with Vice-President Al Gore declaring them the Holy Grail of fossil fuel replacement.    Unfortunately, no quality science agreed with that assessment yet they have been passed into law anyway by anti-science politicians who saw a way to please part of the voter base.

The concern then became, once mandates and subsidies were in place, of course, that not only would biofuels not be better for the environment and people, they may be worse.    A new memorandum  from the Norwegian Institute of Public Health and the Climate and Pollution Agency (formerly SFT) to the Ministry of Health and Care Services and the Ministry of the Environment has sort-of good news - namely, that up to seven percent biodiesel blended in regular diesel will presumably not cause greater health risks for the population than the use of pure fossil diesel. 

That's not to say there should be more.   ”A higher content of biodiesel (up to 20 percent) requires more research to assess health effects. This must include different types of biofuels and blending ratios, as well as physical and technical factors that are relevant in Norway," said Per Schwarze from the Norwegian Institute of Public Health.

A number of studies have examined the effects that blending biodiesel in regular diesel has on air emissions, especially for nitrogen oxides (NOx) and particulates, and most reports show that NOx emissions increase slightly. However the particle mass in the emissions seems to decrease. The size distribution and number of particles can be changed by blending in biodiesel, which can affect health. 

Knowledge about the possible health effects from the use of biofuels is limited. There have been few studies of biodiesel exhaust on humans and animals. Therefore, much is based on studies of gene and cell damage and inflammatory responses in cell cultures. Overall, the present studies suggest that there are not very large differences between the effects of biodiesel and diesel.

Studies indicate that the effect of processing equipment, such as particle filters, is as important as the use of diesel type. The results seem to depend on several factors, such as driving cycle, temperature, engine type, fuel mixture and filtering equipment. 

For increased blending of biodiesel (up to 20-30 per cent) more research is required, so here is hoping activists do not spend a lot of money getting politicians to mandate them. This applies both to the choice of biofuels (including second generation) and different blending ratios between biodiesel and diesel in order to study possible interaction effects on health.