Ethanol Refineries May Emit More Smog-Forming Compounds Than Expected

Refineries that produce ethanol fuel may be releasing much larger amounts of smog-forming compounds than researchers and government agencies had suspected, according to a new study in the Journal of Geophysical Research: Atmospheres. Airborne measurements downwind from an ethanol refinery in Illinois show that, compared to government estimates, ethanol emissions are 30 times higher and emissions of all volatile organic compounds (VOCs), which include ethanol, are five times higher. Producing one kilogram of the fuel at the Illinois refinery emits 170 times more ethanol than what comes out of a vehicle burning the same amount, the study says. Along with nitrogen oxides, VOCs can react with sunlight to form ground-level ozone, the main component of smog. Renewable fuel standards mandate that gasoline burned in the U.S. contains 10 percent ethanol — an attempt to reduce greenhouse gas emissions and petroleum imports while boosting the renewable fuels sector.