The leaves indicate pollution levels

The leaves attract iron oxide particles on the surface, making them magnetic. So they can become inexpensive sensors that assess pollution.

Plant leaves that grow along the roads can serve as a sensor to determine the level of pollution, a study said.

The most exhaust of vehicles is diesel-powered vehicles that contain a large amount of extremely small particles of different sizes. Geophysicist Bernarrd Housen, of the University of West Washington, said that although particles with a size of more than 10 microns can be trapped in the upper respiratory system, particles less than 2.5 microns in size still pass through. Deep in the lungs to cause disease and inflammation.

(Photo: Sadie Belica, University of West Washington at Bellingham)

When Housen and his colleague Luigi Jovane analyzed leaves picked at different points in the street in Ballingham, they found that the magnetism of the leaves along the bus line was 10 times higher than the leaves collected at the sites. Quiet residential neighborhood. The magnetic appearance is due to the iron oxide particles in the exhaust being trapped on the rough surface of the leaves.

Smaller iron oxide particles have specific magnetic properties while particles above 10 microns are not. Rain water washes 30% of the seeds on the leaves, which even the ultrasound does not completely clean. This makes the leaves become a heavy ' candidate ' of environmental pollution investigation. In addition, the leaves are very . cheap, providing information about air quality in each region.

Scientists can from iron oxide particles to visualize the total number of other chemicals in the air. Because many air quality standards are based on leaf exposures in a short period of time, from leaf analysis, scientists also calculate how pollutant particles accumulate during plant maturation. .

The leaves indicate the level of pollution in the streets of many vehicles.