Stanford Atmospheric Chemist: Ethanol Blends Worse Polluters Than Normal Gasoline

April 23rd, 2007 12:01 AM

Did you hear about that report released last week from a Stanford University atmospheric chemist demonstrating that the tailpipe emissions from cars using E85 ethanol are actually more dangerous than those using normal gasoline? You didn’t?

Hmmm. What a shock.

Anyway, Environmental Science & Technology reported Wednesday (emphasis added throughout, h/t NB member Dahlia Travers):

When Mark Jacobson heard a venture capitalist tout ethanol fuel as a solution to air pollution last year, he was surprised—and intrigued. Jacobson, an atmospheric chemist at Stanford University, knew that air quality got worse during Brazil's big ethanol push in the 1970s and that the reason was still unclear.

You don’t hear a lot about Brazil’s pollution woes, do you? Well, Jacobson’s instincts were quite strong:

Jacobson decided to use his sophisticated air-pollution model to put ethanol to the test. Would switching the U.S. fleet to white lightning make the country breathe easier?

His results, published today on ES&T's Research ASAP website (DOI: 10.1021/es062085v), show that ethanol is no silver bullet for health. Switching to E85 blends (85% ethanol, 15% gasoline) could result in slightly higher ozone-related mortality, hospitalization, and asthma (9% higher in Los Angeles and 4% higher in the U.S. as a whole), the study finds. Cancer rates would be similar for gasoline and E85.

Starting to make sense why you didn’t hear much about this? The article continued:

“It's true that ethanol does decrease some pollutants, but it also increases some others," Jacobson says. Compared with gasoline, ethanol tends to produce less benzene and butadiene, but more acetaldehyde and formaldehyde, when burned.

The result: more ozone and about 185 more deaths per year across the U.S., with 125 of those in Los Angeles. Jacobson studied that city in depth because of its ongoing smog problem and found that it has the right atmospheric chemistry to make the ethanol switch particularly problematic.

Shocking. But there was more:

Previous studies have estimated the pollution and health effects of burning ethanol, but Jacobson says those researchers simply scaled up tailpipe emissions and plugged those numbers into outdated formulas to calculate ozone changes and cancer rates. His atmospheric model, called GATOR-GCMOM, accounted for the transport of tailpipe emissions across the U.S. along with chemical transformations in the atmosphere—key components that had been neglected in previous studies.

Think about that last paragraph the next time you hear a global warming alarmist talk about a scientific consensus:

The findings suggest that ethanol cannot be promoted simply as a boon to public health, Jacobson adds. Other factors need to be studied and weighed before ethanol use is made widespread, he says, such as greenhouse-gas emissions, U.S. dependence on foreign oil, and the environmental impacts of growing plants for ethanol.

And, consider the article’s conclusion as well:

But rushing ahead to fix one problem can create another, cautions Hadi Dowlatabadi of the University of British Columbia (Canada). In a previous ES&T study, he found that a U.K. policy designed to reduce carbon emissions created air-quality problems by encouraging particulate-spewing diesel vehicles. He praised the new paper for "trying to point out an issue ahead of time".

Maybe all the global warming alarmists should pay heed, dontcha think?