Fleet-wide use of E85 in the United States could increase the number of respiratory-related deaths and hospitalizations, according to a new study by Stanford University professor Mark Jacobson. His findings are published online in the journal Environmental Science & Technology (ES&T).
Jacobson combined an air pollution/weather forecast model with future emission inventories, population data, and health effects data to examine the effect of converting from gasoline to E85 on cancer, mortality, and hospitalization in the US as a whole and Los Angeles in particular.
After accounting for projected improvements in gasoline and E85 vehicle emission controls, the study found that E85 may increase ozone-related mortality, hospitalization, and asthma by about 9% in Los Angeles (120 deaths/year with a range of 47-140/yr) and 4% in the US as a whole (185 deaths/yr with a range of 72-216/yr) relative to 100% gasoline.
E85 also increased hospitalization by about 650 and 990 in Los Angeles and the US, respectively, and asthma-related emergency-room visits by about 770 and 1,200 in Los Angeles and the US, respectively.
While the simulations found that E85 vehicles reduced atmospheric levels of benzene and butadiene—two carcinogens—compared to gasoline vehicles, the E85 vehicles increased levels of formaldehyde and acetaldehyde—two other carcinogens. As a result, cancer rates for E85 are likely to be similar to those for gasoline.
Due to its ozone effects, future E85 may be a greater overall public health risk than gasoline. However, because of the uncertainty in future emission regulations, it can be concluded with confidence only that E85 is unlikely to improve air quality over future gasoline vehicles. Unburned ethanol emissions from E85 may result in a global-scale source of acetaldehyde larger than that of direct emissions.
The projected health effects of E85 would be the same regardless of feedstock or process.
“Effects of Ethanol (E85) Versus Gasoline Vehicles on Cancer and Mortality in the United States”; Mark Z. Jacobson, Environ. Sci. Technol., ASAP Article 10.1021/es062085v S0013-936X(06)02085-2