Air Date: Week of May 6, 2005

Living on Earth's Katie Olivieri reports how a touch of lemon juice could clean up diesel engines and their emissions.

Transcript

GELLERMAN: It’s Living on Earth. I’m Bruce Gellerman, and coming up: We take a ride on a two-wheeled magic carpet. First, this Note on Emerging Science from Katie Oliveri.

OLIVERI: Lemon juice is not only an environmentally friendly household cleaning solution, but it may also do wonders for your diesel-powered car and the air. A catalytic converter is designed to reduce the amount of emissions from the automobile. The device found in diesel engines uses a heated platinum catalyst to combust unburned hydrocarbons, therefore reducing emissions of carbon monoxide, hydrocarbons and nitrous oxide, which contribute to smog. Although converters are self-cleaning devices, there is one problem. Sulphur in fuel and phosphorus in oil additives can clog them, preventing converters from doing their job efficiently. Scientists from Madrid, Spain found a “solution” to the problem. They discovered that a simple wash of diluted citric acid, the substance present in lemon juice, could effectively clean catalytic converters in diesel-powered cars. Past scientific tests have shown that while other strong acids clearly removed blockage in converters, they also ate away at the heat-conducting platinum. Citric acid, however, washes out catalyst destroyers without damaging the metal. A six-hour citric wash removed 82 percent of phosphorous and about 90 percent of sulphur from a catalyst in a diesel-fuelled vehicle. Currently, although converters should last the course of an average car’s run, about 149,000 miles, 90 percent of them fail before reaching roughly 50,000 miles. Scientists hope regular cleaning will save drivers big bucks, since replacing a converter costs as much as a brand-new engine. Spring cleaning just took on a whole new meaning. That’s this week’s Note on Emerging Science. I’m Katie Oliveri.