SomeÂ biofuelsÂ cause more health problems than petrol and diesel, according to scientists who have calculated the health costs associated with different types of fuel.
The study shows that corn-based bioethanol, which is produced extensively in the US, has a higher combined environmental and health burden than conventional fuels. However, there are high hopes for the next generation of biofuels, which can be made from organic waste or plants grown on marginal land that is not used to grow foods. They have less than half the combined health and environmental costs of standard gasoline and a third of current biofuels.
The work adds to an increasing body of research raising concerns about the impact ofÂ modern corn-based biofuels.
Several studies last year showed that growing corn to make ethanol biofuels was pushing up the price of food. Environmentalists have highlighted other problems such deforestation to clear land for growing crops to make the fuels. The UK government's renewable fuels advisors recommended slowing down the adoption of biofuels until better controls were in place to prevent inadvertent climate impacts.
Using computer models developed by theÂ US Environmental Protection Agency, the researchers found the total environmental and health costs of gasoline are about 71 cents (50p) per gallon, while an equivalent amount of corn-ethanol fuel has associated costs of 72 cents to $1.45, depending on how it is produced.
The next generation of so-called cellulosic bioethanol fuels costs 19 cents to 32 cents, depending on the technology and type of raw materials used. These are experimental fuels made from woody crops that typically do not compete with conventional agriculture. The results are published online today in theÂ Proceedings of the National Academy of Sciences.
"The dialogue so far on biofuels has been pretty much focused on greenhouse gases alone," said David Tilman, a professor at the department of ecology, evolution and behaviour at theÂ University of Minnesota. "And yet we felt there were many other impacts that were positive or negative not being included. We wanted to expand the analysis from greenhouse gases to at least one other item and we chose health impacts."
Article Continues:Â http://www.guardian.co.uk/environment/2009/feb/02/biofuels-health