Biofuels (Corn-based ethanol) more harmful to humans than petrol and diesel, warn scientists

Biofuels more harmful to humans than petrol and diesel, warn scientists

Corn-based bioethanol has higher burden on environment and human health, says US study

Alok Jha, green technology correspondent
guardian.co.uk, Monday 2 February 2009 22.05 GMT

Some biofuels 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.

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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 the http://www.epa.gov/">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.

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Climate change and health costs of air emissions from biofuels and gasoline

Contributed by David Tilman, December 16, 2008 (sent for review August 14, 2008)

Abstract

Environmental impacts of energy use can impose large costs on society. We quantify and monetize the life-cycle climate-change and health effects of greenhouse gas (GHG) and fine particulate matter (PM_2.5) emissions from gasoline, corn ethanol, and cellulosic ethanol. For each billion ethanol-equivalent gallons of fuel produced and combusted in the US, the combined climate-change and health costs are $469 million for gasoline, $472–952 million for corn ethanol depending on biorefinery heat source (natural gas, corn stover, or coal) and technology, but only $123–208 million for cellulosic ethanol depending on feedstock (prairie biomass, Miscanthus, corn stover, or switchgrass). Moreover, a geographically explicit life-cycle analysis that tracks PM_2.5 emissions and exposure relative to U.S. population shows regional shifts in health costs dependent on fuel production systems. Because cellulosic ethanol can offer health benefits from PM_2.5 reduction that are of comparable importance to its climate-change benefits from GHG reduction, a shift from gasoline to cellulosic ethanol has greater advantages than previously recognized. These advantages are critically dependent on the source of land used to produce biomass for biofuels, on the magnitude of any indirect land use that may result, and on other as yet unmeasured environmental impacts of biofuels.

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"Corn requires nitrogen fertilisers and some of that comes on as ammonia, which is volatilised into the air," said Tilman. "The ammonia particles are charged and they attract fine dust particles. They stick together and form particles of the size of 2.5 micron and that has significant health impacts. …