Ethanol continues to serve as one of the most inexpensive and effective tools available for reducing harmful emissions from the transportation sector. While much of the focus in recent years has been on ethanol’s ability to reduce greenhouse gas (GHG) emissions, ethanol also plays a critical role in reducing tailpipe emissions of pollutants that cause smog and ground-level ozone and adversely affect human health.
The ethanol molecule is 35% oxygen, meaning it burns more cleanly and completely than petroleum-based hydrocarbons in gasoline. By displacing petroleum-derived substances like aromatics in gasoline, ethanol helps reduce emissions of air toxics, particulate matter, carbon monoxide, nitrous oxides and exhaust hydrocarbons.
Reducing these emissions means fewer cases of respiratory illness and asthma, heart disease, lung disease, cancer and even fewer premature deaths. A study by the University of California-Berkeley found that human lives across the U.S. would be extended by replacing gasoline with biofuels: “A biofuel eliminating even 10-percent of current gasoline pollutant emissions would have a substantial impact on human health in this country, especially in urban areas.” Specifically, the researchers found that replacing gasoline with biofuels like ethanol reduces occurrence of direct particulate matter and indirect fine particles, volatile organic compounds, ozone and toxic air pollutants.
Ethanol also has a proven track record for reducing GHG emissions. According to a new analysis conducted for the U.S. Department of Agriculture (USDA), corn ethanol from a typical dry mill reduces GHG emissions by 43% compared to gasoline – even when hypothetical land use change emissions are included. Data from USDA and EPA show that agricultural land use is actually shrinking, undermining the indirect land use change theory. The USDA study found that by 2022, corn ethanol would reduce GHG by 76% compared to gasoline.
Clearing the Air with Ethanol
In addition to reducing GHG emissions, ethanol is the best tool available to reduce tailpipe emissions of other harmful pollutants. Adding ethanol to gasoline reduces tailpipe emissions of the following pollutants, among others:
- Carbon monoxide, which can cause harmful health effects by reducing oxygen delivery to the body’s organs.
- Exhaust hydrocarbons, which contribute to ozone, irritate the eyes, damage the lungs, and aggravate respiratory problems.
- Air toxics like benzene, which can cause cancer and reproductive effects or birth defects.
- Fine particulate matter, which can pass through the throat and nose and enter the lungs, causing serious health effects.