Wednesday, April 18, 2007
WEDNESDAY, April 18 (HealthDay News) -- While ethanol is promoted as an eco-friendly, clean-burning fuel for cars, its widespread use could pose a threat to human health, according to a Stanford University study.
Atmospheric scientist Mark Z. Jacobson concluded that if every vehicle in the United States was powered by fuel made primarily from ethanol instead of gasoline, there would likely be an increase in the number of respiratory-related deaths and hospitalizations.
The study is in the April 18 online edition of the journalEnvironmental Science & Technology.
Jacobson used a computer model to simulate what air quality conditions in the United States would be in 2020, if there was widespread use of vehicles fueled by E85, a blend of 85 percent ethanol and 15 percent gasoline.
"We found that E85 vehicles reduce atmospheric levels of two carcinogens, benzene and butadiene, but increase two others -- formaldehyde and acetaldehyde," Jacobson said in a prepared statement. "As a result, cancer rates for E85 are likely to be similar to those for gasoline. However, in some parts of the country, E85 significantly increased ozone, a prime ingredient of smog."
The computer model showed ozone increases in Los Angeles and the northeastern U.S., but a decrease of ozone in the southeast.
"In our study, E85 increased ozone-related mortalities in the United States by about 200 deaths per year compared to gasoline, with about 120 of those deaths occurring in Los Angeles," Jacobson said. "These mortality rates represent an increase of about four percent in the U.S. and nine percent in Los Angeles above the projected ozone-related death rates for gasoline-fueled vehicles in 2020."
The study also found that E85 would likely increase the number of asthma-related emergency room visits in the United States by 770 a year and the number of respiratory-related hospitalizations by 990 a year.
The harmful effects of E85 would be the same, whether the ethanol is made from corn, switchgrass or other kinds of plants, Jacobson said. He questioned the wisdom of promoting ethanol and other biofuels if they cause as much harm as pollution from gasoline, which causes about 10,000 premature deaths a year in the United States.
"There are alternatives, such as battery-electric, plug-in hybrid and hydrogen fuel cell vehicles, whose energy can be derived from wind or solar power. These vehicles produce virtually no toxic emissions or greenhouse gases and cause very little disruption to the land -- unlike ethanol made from corn or switchgrass, which will require millions of acres of farmland to mass-produce," he said.
The American Academy of Family Physicians has more about air pollution and health.
SOURCE: Stanford University, news release, April 18, 2007