Warning is sounded on ethanol use
Ethanol, widely touted as a greenhouse-gas-cutting fuel, would have serious health effects if heavily used in cars, producing more ground-level ozone than gasoline, particularly in the Los Angeles Basin, according to a Stanford University study out today.
"Ethanol is being promoted as a clean and renewable fuel that will reduce global warming and air pollution," said Mark Z. Jacobson, an associate professor of civil and environmental engineering and author of the study in the online edition of Environmental Science and Technology. "But our results show that a high blend of ethanol poses an equal or greater risk to public health than gasoline, which already causes significant health damage."
Ozone is a key ingredient in smog, and when inhaled even at low levels it can harm lungs, aggravate asthma and impair immune systems.
The health effects from ethanol use are the same whether it is made from corn or other plant products, Jacobson found.
The study determined that a 9% increase in ozone-related deaths would occur in Greater Los Angeles, and a 4% increase nationally, by 2020 if a form of ethanol called E85, were used instead of gasoline. In the Southeast, by contrast, mortality rates would decrease slightly.
The type of fuel used in the study -- 85% ethanol, 15% gasoline -- emits less greenhouse gases than other types, some researchers say.
"Today, there is a lot of investment in ethanol," Jacobson said. "The question is, if we're not getting any health benefits, then why continue to promote ethanol?"
He used a computer model to simulate air quality in 2020 -- when ethanol-fueled vehicles are expected to be widely available in the United States -- with a focus on Los Angeles. His study is the first to combine emissions data with multiple other variables, including climate, population density and current amounts of air pollution, he said.
"The chemicals that come out of a tailpipe are affected by a variety of factors, including chemical reactions, temperatures, sunlight, clouds, wind and precipitation," he said.
"Overall, health effects depend on exposure to these airborne chemicals, which varies from region to region
President Bush has made increased use of ethanol and other alternative fuels a centerpiece of his strategy to increase reliance on domestic fuels while reducing greenhouse gas emissions.
