No, they will not stick to a refrigerator, but magnetized leaves are proving a promising new way to study the amount of pollution in cities.
Western geology professor Bernie Housen found that tree leaves collect materials in car exhaust, which can allow researchers to determine an area’s pollution levels. The pollutants on the leaves can be detected and measured using a magnetic field.
“This way of measuring through leaves is cheaper and more effective,” he said. “We are able to measure the distribution of pollution over areas with the effects of traffic.”
Housen has based his experiment off studies conducted in Germany and Italy.
Luigi Jovane, a research associate in Western's geology department, said the results yielded in those areas were skewed because of the dust from Piscinas' Desert in Italy and the amount of factories present in Germany.
In comparison to Germany and Italy, Jovane said Bellingham is a well-sized city to conduct the experiment in because it is small and has normal urban activity, with no abnormal outside influences.
“Our dream is to understand the amount of pollution in a single place,” Jovane said.
Jovane has worked with Housen on the project since they started collecting samples May 15.
Housen received funding from Western’s Advanced Materials Science and Engineering Center a couple of years ago, but because of problems with the budget, he was not able to begin until this year.
Western senior Sadie Belica worked with Housen and collected maple tree leaves from six trees along High Street and Indian Street, and then took a microscopic picture of the particles on the leaf and measured their size.
Housen and Jovane collected leaf samples from Whatcom Park and valleys around Mount Baker to use as a control for the experiment.
“This way we can discern which is natural dust and which amount is caused by traffic,” Jovane said.
Leaves were also taken from trees on Roeder Avenue, where there is heavy locomotive travel and Meridian Street where more than 30,000 cars travel each day, Housen said.
“We put the samples in a machine called the Vibrating Sample Magnetometer,” Housen said. “We take a piece of the leaf and put the sample into a gelatin sample tube, similar to a pill.”
The machine gradually applies a strong magnetic field to the sample, and the magnetic particles trapped on the leaf are measured.
Housen said the sampling process can take less than a minute for a strong sample or three to four hours if the sample is weak.
Their results found leaves on Indian Street were more magnetic than those on High Street where there is no bus route.
A growing concern involves the health risks with an abundance of exhaust in the air.
“The test is helpful for cities putting in bike routes on bus routes,” he said. “Those people are physically active and breathing in small particles, which puts them at a higher risk for health problems.”
The Environmental Protection Agency has established standards for each city for the size of small particles that float around in the air.
When inhaled, the smallest particles can reach the deepest parts of the lungs and can cause health issues over time.
Housen said Bellingham is on the lower side for magnetic concentration, but hopes this research can help bikers and pedestrians alter their route if they normally take a route near the bus line.
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