A study published in the April 18 online edition of the journal Environmental Science & Technology
suggests that despite the fact that biofuels are regarded to be more environmentally friendly, ethanol-based fuels may actually pose more health hazards than pure gasoline.

"We found that E85 vehicles reduce atmospheric levels of two carcinogens, benzene and butadiene, but increase two others-formaldehyde and acetaldehyde," Jacobson said. "As a result, cancer rates for E85 are likely to be similar to those for gasoline. However, in some parts of the country, E85 significantly increased ozone, a prime ingredient of smog."
"In our study, E85 increased ozone-related mortalities in the United States by about 200 deaths per year compared to gasoline, with about 120 of those deaths occurring in Los Angeles," Jacobson said. "These mortality rates represent an increase of about 4 percent in the U.S. and 9 percent in Los Angeles above the projected ozone-related death rates for gasoline-fueled vehicles in 2020."

The author of the study thus recommend other alternatives, such as battery-electric, plug-in-hybrid and hydrogen-fuel cell vehicles, whose energy can be derived from wind or solar power.

Source: Stanford News