• Using ethanol-blended fuel has a positive impact on air quality. Ethanol is an oxygenate, and that oxygen helps the fuel burn more cleanly and more completely - a cleaner fuel for cleaner air.
• Many areas of the country have used ethanol in order to meet EPA clean air standards with great results. Ethanol reduces the emissions of carbon monoxide, volatile organic compounds, and toxic air emissions.
• Ethanol reduces tailpipe carbon monoxide emissions by as much as 30%, toxics content by 13% (mass) and 21% (potency), and tailpipe fine particulate matter (PM) emissions by 50%.
• Ethanol also reduces secondary PM formation by diluting aromatic content in gasoline.  Over half of the air pollution attributable to vehicles comes from "high emitting" vehicles that make up only 10% of the vehicle fleet. High emitters include older vehicles as well as well as newer cars with malfunctioning pollution control systems. The use of ethanol-blended fuel is also one of the best pollution control strategies for off-road vehicles, including motorcycles, ATVs and snowmobiles, which represent a significant source of emissions. Source:  Smog Reyes, February 2004

In 2006, ethanol use in the U.S. reduced C02-equivalent greenhouse gas emissions by approximately 8 million tons, equal to removing the annual emissions of more than 1.21 million cars from the road (Argonne's GREET 1.7 Model).