Defending E85 study

Recent studies on the life-cycle of E85 versus gasoline show there is no carbon benefit of most ethanol forms.

Robert Moffitt, in his opinion piece in the March 31 Daily (“Against E85, for windmills”), made inaccurate statements about my published research and about the health risks of 85 percent blended ethanol (E85) that I would like to correct.

First, he states, “He first selected the emission studies that best fit his hypothesis.” This statement is inaccurate. The study (which can be found at considered all 12 studies that were available at the time without bias. Subsequent data have demonstrated that the emission assumptions were exactly consistent with respect to nitrogen oxides and conservative with respect to organic gases. As such, the effects of E85 are most likely more damaging than the study predicted.

Second, he claims that he “plugged in predicted weather/climate patterns 14 years in the future.” This is inaccurate as present-day as well as 2020 simulations were performed, and the model has been demonstrated to predict the weather for the present day. The effects today were estimated as more severe than 2020.

Although it has been about a year since the paper was published, no peer-reviewed paper has challenged the results. The only challenges have come from advocates, such as Moffitt, and those with a financial interest in ethanol, such as the Renewable Fuels Association and venture capitalists, but not scientists. It should also be noted that the American Lung Association of the Upper Midwest, who Moffitt represents, does not represent other American Lung Association branches, who have not acted as advocates of E85 to nearly the same extent. The ALAUM Web site ( in fact misinforms the public about E85. It states, for example, that “E85 can reduce tailpipe emissions such as ozone-forming pollutants by about 20 percent.” This is incorrect, as E85 increases organic gas emissions in nearly all known studies to date and the nitrogen oxide reductions due to E85 increase ozone in most polluted cities of the United States.

Further, the study I did is still the only published study worldwide to date to examine the effects of E85 on outdoor ozone in the United States, and the results of my study do not draw this conclusion. As such, ALAUM is making estimates it has no ability to make. Finally, it states that “a typical FFV driver can prevent 4 tons of lifecycle carbon dioxide emissions … with E85 …” All of the latest scientific studies on the lifecycle of E85 versus gasoline show that there is no carbon benefit of most forms of ethanol. A detailed explanation of the recent research is summarized for the general audience in a cover story in Time Magazine. It is time Moffitt and other advocates provide the public with accurate information about the air they should be protecting.

Mark Z. Jacobson is Professor of Civil and Environmental Engineering, Professor by Courtesy of Energy Resources Engineering Director, Atmosphere/Energy Program at Stanford University. Please send comments to [email protected].