Corn ethanol is no better fuel than gasoline, and it may even be worse for air quality, according to a new University of Minnesota study.

The study, released Monday, is the first one to estimate the economic costs to human health and well-being from three different fuels -- gasoline, corn-based ethanol and cellulosic (plant-based) ethanol -- its authors say.

Scientists and economists looked at life-cycle emissions of growing, harvesting, producing and burning different fuels, and concluded that ethanol made from switchgrass and other plant materials is far better than either corn ethanol or gasoline.

"Our study shows that if we're really going to make choices in the best interest of the public, we need to look not only at what's cheapest to produce, but what are the costs to the public in terms of environmental and health effects," said Jason Hill, research associate in applied economics and a resident fellow at the U's Institute on the Environment.

Ethanol is a $6 billion industry in Minnesota, according to state estimates. The Minnesota Department of Agriculture calculated that the 17 ethanol plants in the state produced 670 million gallons of ethanol in 2007 and provided 26,000 "direct impact" jobs.

The university's study will be published in this week's issue of the Proceedings of the National Academy of Sciences and was posted online on Monday afternoon at the PNAS site.

No love from ethanol backers

Ethanol advocates said they haven't seen the study and will need time to understand how the conclusions were reached.

"I'm stifling a yawn," said Mark Hamerlinck, communications director for the Minnesota Corn Growers Association. "It would be news if the university had anything positive to say about corn ethanol. It's how they make a living over there."