And not only because it's raising tortilla prices in Mexico:
Switching from gasoline to ethanol — touted as a green alternative at the pump — may create dirtier air, causing slightly more smog-related deaths, a new study says.
Nearly 200 more people would die yearly from respiratory problems if all vehicles in the United States ran on a mostly ethanol fuel blend by 2020, the research concludes.
....Each year, about 4,700 people, according to the study's author, die from respiratory problems from ozone, the unseen component of smog along with small particles. Ethanol would raise ozone levels, particularly in certain regions of the country, including the Northeast and Los Angeles.
"It's not green in terms of air pollution," said study author Mark Jacobson, a Stanford University civil and environmental engineering professor. "If you want to use ethanol, fine, but don't do it based on health grounds. It's no better than gasoline, apparently slightly worse."