More Fuel for the Ethanol Debate
Switching from gas to ethanol might create a new health hazard. A study appearing in the journal Environmental Science & Technology this week suggests that fumes from ethanol are no safer than those from gasoline and that, by 2020, the number of smog-related deaths per year in the United States would increase slightly (from about 10,000 to 10,185) if all vehicles used E85, a gasoline alternative made primarily of ethanol. The study, led by Mark Jacobson, an atmospheric chemist at Stanford University and an authority on atmospheric dynamics and air pollutants, also foresees an increase in two major carcinogens at the same time that two others would drop, suggesting that cancer rates from ethanol tailpipe emissions would remain at current levels.
"Converting vehicles to E85 is not going to improve air pollution; it could even make the problem worse," says Jacobson. His findings are based on a computer model that considers not only the total amount of ethanol tailpipe emissions that would enter the atmosphere but also how those emissions might disperse and change because of real-world factors such as wind patterns, clouds, and climate. The model, which Jacobson has been developing for almost two decades and has used to analyze other atmospheric pollution issues, predicts that ozone, a component of smog and a known health hazard, would increase over Los Angeles and the Northeast, for example.
Critics of the study say the model has flaws. "He didn't look at one very important pollutant, which is greenhouse gas," says Roland Hwang, senior policy analyst at the Natural Resources Defense Council, an environmental group that advocates the use of ethanol. Hwang says that using ethanol will reduce global warming by minimizing the amount of greenhouses gases released and that curbing global warming will in turn reduce smog levels and cut deaths. Hwang also argues that it would be impossible to convert all vehicles to ethanol as quickly as the model assumes, so that Jacobson's assumptions about nitrogen oxide levels, a precursor of smog, are not correct. "It doesn't reflect what's happening, and it doesn't tell us anything new," Hwang says of the study.
Jacobson, who advocates dropping all ethanol subsidies and moving toward electric or hydrogen fuel-cell cars energized by electricity from wind power, says he's worried that politics is leading to misinterpretation of his work. "NRCD went out on a limb in support of ethanol early on. Now they're defending the decision. People don't want to accept that ethanol might not be as good as everybody said it was," he says. "My goal is simply to bring correct information to people."
The study is sure to add another yet another wrinkle to the already rancorous debate about the wisdom of pursuing ethanol as an alternative to gasoline. During the State of the Union address in January, President Bush put the spotlight on ethanol when he called for annual production to reach 35 billion gallons by 2017. Scientists and policymakers have debated whether corn ethanol will compete with food corn for space, whether it takes more energy to produce than it yields, and whether making the switch to cellulosic ethanolwhich produces more energy than corn ethanolis feasible.