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Ethanol-fueled cars will create an equal or even greater risk to public health than those powered by gasoline, according to a new study. Gasoline emissions are estimated to cause at least 10,000 premature deaths in the United States alone every year. Yet ethanol is no panacea, says Mark Z. Jacobson, the Stanford University atmospheric scientist who conducted the study.

Using sophisticated computer modeling techniques to simulate air quality in the United States in 2020, Jacobson found that vehicles fueled by a blend of 85 percent ethanol and 15 percent gasoline (E85) increase atmospheric concentrations of formaldehyde and acetaldehyde, canceling out the reduction of carcinogens that are prevalent in gasoline but not in ethanol. What's more, E85 can increase ozone in some areas. And that means ugly smog and the deaths associated with higher levels of ozone. Jacobson projects that widespread adoption of E85 would lead to slightly higher mortality rates in the United States (+4 percent) and especially smog-friendly Los Angeles (+9 percent).

And it doesn't matter, according to Jacobson, whether ethanol is made from corn, switchgrass or other plant products—the results remain the same. So we have yet another reason to be skeptical of the prevailing obsession with ethanol. Well, what should we do? Jacobson highlights alternatives such as battery-electric, plug-in-hybrid and hydrogen-fuel cell vehicles, which can derive energy from wind or solar power. He says, "These vehicles produce virtually no toxic emissions or greenhouse gases and cause very little disruption to the land."