Gasoline-to-ethanol switch reduces number of tiny, harmful particles in the air

New research claims that the concentration of ultrafine particles less than 50 nanometres in diameter, which studies have shown to be harmful to human health, increases in the air when motorists switch from ethanol-to-gasoline.

Carried out by Franz M Geiger, a professor of chemistry at the National University of Singapore, the research found that when higher ethanol prices pushed drivers in Sao Paulo, Brazil, to switch to gasoline, the number of ultrafine nanoparticles increased by a third.

In addition, when ethanol prices went down, in turn causing some two million Sao Paulo drivers to switch back to the fuel, the concentration of nanoparticles also went down.

Currently, environmental protection agencies across the world do not measure or regulate particles of the size looked at in the study, despite research showing they can be harmful to human health.

"We studied São Paulo, but there are many North American cities, including Chicago, with similar air chemistry, especially spring through fall," said Franz M. Geiger, professor of chemistry in Northwestern's Weinberg College of Arts and Sciences.

"The push we are seeing in large cities away from gasoline and toward vehicles powered by ethanol, electricity or a mix of the two will result in a reduction of these ultrafine particles. This likely comes with a health benefit -- these particles, below one micron, have the potential to get deeply into your lungs," he said.

Sao Paulo supplied a unique opportunity for Geiger and colleague Alberto Silva, a professor of economics. Sao Paulo consumers can and do switch between fuels for reasons unrelated to air quality, such as costs. This meant the city provided a perfect subject for studying the effects of people’s behaviour at fuel pumps on urban air quality.

"With this knowledge, we hope more money and human resources will be invested in trying to understand and possibly monitor these ultrafine particles," said Salvo. "The big unknown is what type of particles are the most harmful to health."

The study has been published in the journal, Nature Communications.

 

This article was written by Daryl Worthington, assistant editor of Biofuels International