Ethanol blends as a transport fuel alternative, has been heralded as a “green fuel” which emits lower greenhouse gases compared to conventional fossil fuels. A new study based on a sophisticated air pollution/weather forecasting model shows that while ethanol blends may decrease some pollutants (like benzene and butadiene), it may also increase others (like acetaldehyde and formaldehyde). This study by Stanford University Associate Professor, Mark Jacobson, shows that increased use of E85 (a blend of 85% ethanol and 15% gasoline) may lead to a 9% increase in ozone related-deaths in greater Los Angeles and an 4% increase U.S. national average of the same deaths by 2020. The study (recently featured in the journal, Environmental Science and Technology) concludes that “E85 is unlikely to improve air quality over future gasoline vehicles” and that “unburned ethanol emissions from E85 may result in a global-scale source of (the pollutant) acetaldehyde larger than that of direct emissions”..