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Old 02-03-2009, 10:33 AM   #1
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Default Cellulosic Ethanol May Benefit Human Health And Help Slow Climate Change

ScienceDaily (Feb. 3, 2009) — Filling our fuel tanks with cellulosic ethanol instead of gasoline or corn-based ethanol may be even better for our health and the environment than previously recognized, according to new research from the University of Minnesota.

The study finds that cellulosic ethanol has fewer negative effects on human health because it emits smaller amounts of fine particulate matter, an especially harmful component of air pollution. Earlier work showed that cellulosic ethanol and other next-generation biofuels also emit lower levels of greenhouse gas emissions.

The study will be published in the journal Proceedings of the National Academy of Sciences in February and will be posted online next week.

"Our work highlights the need to expand the biofuels debate beyond its current focus on climate change to include a wider range of effects such as their impacts on air quality," said lead author Jason Hill, a resident fellow in the University of Minnesota's Institute on the Environment.

The study is the first to estimate the economic costs to human health and well-being from gasoline, corn-based ethanol and cellulosic ethanol made from biomass. The authors found that depending on the materials and technology used in production, cellulosic ethanol's environmental and health costs are less than half the costs of gasoline, while corn-based ethanol's costs range from roughly equal to about double that of gasoline.

Total environmental and health costs of gasoline are about 71 cents per gallon, while an equivalent amount of corn-ethanol fuel costs from 72 cents to about $1.45, depending on the technology used to produce it. An equivalent amount of cellulosic ethanol, however, costs from 19 cents to 32 cents, depending on the technology and type of cellulosic materials used.


"These costs are not paid for by those who produce, sell and buy gasoline or ethanol. The public pays these costs," said study co-author Stephen Polasky, a professor in the university's applied economics department.

The authors looked at pollutants emitted at all stages of the life cycles of the three types of fuel, including when they are produced and used. They considered three methods of producing corn-based ethanol and four methods of producing cellulosic ethanol.

"To understand the environmental and health consequences of biofuels we must look well beyond the tailpipe to how and where biofuels are produced. Clearly, upstream emissions matter," Hill said.

The paper also points out that other potential advantages of cellulosic biofuels, such as reducing the amount of fertilizer and pesticide runoff into rivers and lakes, may also add to the economic benefit of transitioning to next-generation biofuels.


Full article here:
http://www.sciencedaily.com/releases...0202174934.htm
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Old 02-04-2009, 11:27 AM   #2
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Alternative Ethanol Fuel Won’t Improve Future Air Quality

By Walter Jessen

Ethanol is produced biologically by fermenting sugar with Saccharomyces yeasts. Under anaerobic (meaning in the absence of oxygen) conditions, when yeast metabolize sugar, they produce ethanol and carbon dioxide. Bioethanol (meaning ethanol production derived from crops) is the most common renewable fuel today and is derived from corn grain (starch) and sugar cane (sucrose) [1]. Thus, ethanol is an inherently renewable eco-friendly resource, contributing nothing in itself to greenhouse gases. However, a study published in the journal Environmental Science & Technology (ES&T) concludes that if every vehicle in the U.S. ran on ethanol-based fuel, the number of respiratory-related deaths and hospitalizations would likely increase.

You read that right, widespread use of E85 would likely result in an increase in respiratory-related deaths and hospitalizations.

Stanford University atmospheric chemist Mark Z. Jacobson, author of the study said [2]:

“Ethanol is being promoted as a clean and renewable fuel that will reduce global warming and air pollution, 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.”

Jacobson used a sophisticated 3-D atmospheric computer model that accounted for the transport of tailpipe emissions across the U.S. along with chemical and radiative transformations in the atmosphere - key components that have been neglected in previous studies. He combined the ambient concentrations with health effects and population data to simulate air quality in the year 2020, when ethanol-powered vehicles are expected to be widely available in the U.S. He then determined the health risks due to gasoline and ethanol, and analyzed the results at high resolution in Los Angeles and at lower resolution in the entire U.S.

Jacobson explained that:

“… chemicals that come out of a tailpipe are affected by a variety of factors, including chemical reactions, temperatures, sunlight, clouds, wind and precipitation. 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.”

The results

The study results show that converting to E85 (85% ethanol, 15% gasoline) could result in higher ozone-related asthma, hospitalization and mortality. The death rate increases about 9% in Los Angeles and 4% in the U.S. over projected death rates with gasoline vehicles.

E85 vehicles reduced atmospheric levels of two carcinogens, benzene and butadiene, but increased two others, acetaldehyde and formaldehyde.
As a result, cancer rates for E85 are likely to be similar to those for gasoline. In some parts of the country (Los Angeles and the Northeast), E85 use was projected in increase ozone levels. The oxidant ozone is a well-known air pollutant. According to the Environmental Protection Agency (EPA), ozone inhalation is associated with respiratory tract inflammation and functional alterations of the lung [3]. The increased levels of ozone were partially offset by decreased levels in the Southeast. Nonetheless, future E85 use may be a greater overall public health risk than gasoline. Jacobson concludes that E85 is unlikely to improve air quality over future gasoline vehicles and that unburned ethanol emissions from E85 may result in a global-scale source of acetaldehyde larger than that of direct emissions.

Brazil

Brazil is the only country in the world where a large-scale ethanol fuel program, introduced in 1979, has been implemented. By 1997, approximately 4 million Brazilian automobiles ran on neat ethanol (100% ethanol) and another 9 million ran on an ethanol-gasoline blend (22% ethanol) [4]. Since the introduction of ethanol fuel in Brazil, several studies on air quality have been conducted that confirm Jacobson’s recent projections.

remainder of article at:

http://www.highlighthealth.com/eco-f...e-air-quality/
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Old 02-04-2009, 06:39 PM   #3
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Interesting article dharma, thanks.
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Old 02-04-2009, 07:22 PM   #4
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But there is more. It costs money to store, transport and blend ethanol with gasoline. Since ethanol absorbs water, and water is corrosive to pipeline components, it must be transported by tanker to the distribution point where it is blended with gasoline for delivery to your gas station. That’s expensive transportation. It costs more to make a gasoline that can be blended with ethanol. Ethanol is lost through vaporization and contamination during this process. Gasoline/ethanol fuel blends that have been contaminated with water degrade the efficiency of combustion. E-85 ethanol is corrosive to the seals and fuel systems of most of our existing engines (including boats, generators, lawn mowers, hand power tools, etc.), and can not be dispensed through existing gas station pumps. And finally, ethanol has about 30 percent less energy per gallon than gasoline. That means the fuel economy of a vehicle running on E-85 will be about 25% less than a comparable vehicle running on gasoline.
This is from an interesting article from 2007 here:
http://www.financialsense.com/editor...2007/0202.html
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