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Air Quality Impacts of Ethanol Debated

May 07, 2007

Source: Stanford University, American Coalition for Ethanol

A recent study published by an atmospheric scientist at Stanford University used a sophisticated computer model to predict the air quality impacts of ethanol-fueled vehicles. The Stanford study concluded that ethanol poses a significant public health threat. These findings did not go unchallenged though. 

The Stanford study estimated the air quality impacts in 2020 if all vehicles on the road were powered by E85. Impacts were estimated throughout the U.S. with particular emphasis on Los Angeles. The study found that ozone, a primary cause of smog, was significantly higher in some parts of the country under the E85 scenario. As a result, the study predicts 200 additional deaths and over 1,500 additional hospitalizations per year due to degraded air quality from ethanol. 

The ethanol industry issued a response to the Stanford study that challenges the assumptions and predictions. The industry argues that real world evidence shows that air quality has improved in every city, county, and state that has switched from straight gasoline to ethanol-blended fuel.


The Stanford study’s authors suggest that ethanol may not warrant the current public policy attention it is now garnering. Instead, policies should promote alternatives such as battery-electric, plug-in hybrid, and hydrogen fuel cells, which can have less detrimental impacts on air, land, and water.


For detailed analysis of light-duty vehicles and fuels, including flex-fuel vehicles and E85, see RPN's Responsible Purchasing Guide: Light-Duty Fleet Vehicles 


For an executive summary of the Stanford study visit:


For a response to the study issued by the American Coalition for Ethanol visit:


For a response to the study issued by the Renewable Energy Action Project visit:

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