Warning is sounded on ethanol use
The fuel would create more ground-level ozone than gasoline if used heavily, a study finds. Critics disagree on the overall risk.
Los Angeles Times, April 18, 2007
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
"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&. Since Los Angeles has historically been the most polluted airshed in the U.S., the test bed for nearly all U.S. air pollution regulation and home to about 6% of the U.S. population, it is also ideal for a more detailed study," Jacobson wrote.
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.
In his State of the Union address in January, Bush called for annual national production of 35 billion gallons of ethanol by 2017, up from 5 billion gallons in 2006 and nearly five times the target set by Congress. The president's deputy press secretary requested a copy of Jacobson's study Tuesday but had no immediate comment.
Kristen Hellmer, a spokeswoman for the White House Council on Environmental Quality, said she had not had a chance to review the study, but reiterated the administration's support for ethanol.
"I think there are pollutants that contribute to ozone which may slightly increase as a result of more ethanol use, which can be managed by tools which we have available under the Clean Air Act," Hellmer said.
Jennifer Wood of the U.S. Environmental Protection Agency echoed those remarks in an e-mail.
"While EPA has not fully reviewed the study, the agency's experience and analysis in developing renewable-fuel standards contradicts the underlying assumptions of the study," she wrote. "The increased use of renewable fuels, like E85, will significantly reduce greenhouse gas, benzene and carbon monoxide emissions while strengthening our nation's energy security and supporting American farming communities.
"The pollutants that contribute to ozone, which may slightly increase as a result of additional ethanol use, can be managed by the suite of effective tools available under the Clean Air Act."
California Air Resources Board spokeswoman Gennet Paauwe said staff researchers are designing their own study to examine potential effects of ethanol on air pollution and health.
Jacobson said there are already an estimated 5,000 premature
Brooke Coleman, director of the Renewable Energy Action Project in
"He is ignoring the fact that E85 greatly reduces emissions that are much more harmful to humans than smog, such as toxics and soot" particulates, Coleman said in an e-mail.
Jacobson replied that "there is no evidence available to indicate that particulate matter will decrease with the use of E85&. The effect of E85 on increasing mortality is firmly grounded in science based on information available today, and not misleading. What is misleading is the claims made to date that ethanol will improve air quality and health."
Thirty states, so far, have public E85 fueling stations. Most are in the
Ethanol cars may not be healthier
BBCNews.com, April 18, 2007
Ethanol vehicles may have worse effects on human health than conventional petrol, US scientists have warned.
A computer model set up to simulate air quality in 2020 found that in some areas ozone levels would increase if all cars were run on bioethanol.
Deaths from respiratory problems and asthma attacks would increase with such levels, the researchers reported in Environmental Science and Technology.
The EU has agreed that biofuels should be used in 10% of transport by 2020.
Mark Jacobson, an atmospheric scientist at
In one simulation all vehicles were fuelled by petrol and in the other all vehicles were fuelled by E85 - a mix of 85% ethanol and 15% petrol.
If all cars were run on E85, he found that in some parts of the
In the study, the increase in smog translated to an extra 200 deaths per year in the whole of the
Increases in ozone in some areas of the
Although ethanol was found to reduce levels of two atmospheric carcinogens, levels of others increased so associated cancers would be the same as with pollution caused by petrol fumes, the study showed.
"We found that using E85 will cause at least as much health damage as gasoline, which already causes about 10,000 premature deaths annually from ozone and particulate matter," said Jacobson.
"The question is, if we're not getting any health benefits, then why continue to promote ethanol and other biofuels."
He added: "By comparison, converting all vehicles to battery-electric, where the electricity is from wind energy would eliminate 10,000 air pollution deaths per year and 98% of carbon emissions from vehicles."
In principle, biofuels - ethanol and diesel, made from crops including corn, sugarcane and rapeseed - are a way of reducing greenhouse gas emissions compared to conventional transport fuels.
Although they produce carbon dioxide, growing the plants absorbs a comparable amount of the gas from the atmosphere.
A government report said that biofuels could reduce emissions by 50-60% compared to fossil fuels.
Stuart Shales, senior lecturer in environmental biotechnology at the University of the West England, said there were companies in the
He added that it would not be feasible for all cars to run on ethanol because too much land would be needed to grow the crops.
"What people are looking at are second generation fuels which will be produced from whole biomass, like wood, which can be broken down to fermentable sugars."
"This is the first time I've seen any research about ozone.
"The question I would ask is, has there been any respiratory problems in
Note: This story has been adapted from a news release issued by Stanford University
Science Daily Ethanol is widely touted as an eco-friendly, clean-burning fuel. But if every vehicle in the
"Ethanol is being promoted as a clean and renewable fuel that will reduce global warming and air pollution," said Jacobson, associate professor of civil and environmental engineering. "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."
Gasoline vs. ethanol
For the study, Jacobson used a sophisticated computer model to simulate air quality in the year 2020, when ethanol-fueled vehicles are expected to be widely available in the
"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 explained. "In addition, overall health effects depend on exposure to these airborne chemicals, which varies from region to region. Ours is the first ethanol study that takes into account population distribution and the complex environmental interactions."
In the experiment, Jacobson ran a series of computer tests simulating atmospheric conditions throughout the
Jacobson programmed the computer to run air quality simulations comparing two future scenarios:
A vehicle fleet (that is, all cars, trucks, motorcycles, etc., in the
A fleet powered by E85, a popular blend of 85 percent ethanol and 15 percent gasoline.
Deaths and hospitalizations
The results of the computer simulations were striking.
"We found that E85 vehicles reduce atmospheric levels of two carcinogens, benzene and butadiene, but increase two othersformaldehyde and acetaldehyde," Jacobson said. "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."
Inhaling ozoneeven at low levelscan decrease lung capacity, inflame lung tissue, worsen asthma and impair the body's immune system, according to the Environmental Protection Agency. The World Health Organization estimates that 800,000 people die each year from ozone and other chemicals in smog.
"In our study, E85 increased ozone-related mortalities in the
The study showed that ozone increases in
The deleterious health effects of E85 will be the same, whether the ethanol is made from corn, switchgrass or other plant products, Jacobson noted. "Today, there is a lot of investment in ethanol," he said. "But we found that using E85 will cause at least as much health damage as gasoline, which already causes about 10,000 U.S. premature deaths annually from ozone and particulate matter. The question is, if we're not getting any health benefits, then why continue to promote ethanol and other biofuels?
"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," he added. "These vehicles produce virtually no toxic emissions or greenhouse gases and cause very little disruption to the landunlike ethanol made from corn or switchgrass, which will require millions of acres of farmland to mass-produce. It would seem prudent, therefore, to address climate, health and energy with technologies that have known benefits."
This ES&T study was partially supported by NASA.