Thursday, July 3, 2008

A Living Air Filter

Name : Bel-Air

Description : Uses plants and fans to clear the air of toxic chemicals

Cost to develop : $236,000

Time : 1 year

You home could be emitting toxic gases. Just ask the victims of Hurricane Katrina, whose emergency trailers, made with glue-laden particleboard, let off so much formaldehyde that the Centers for Disease Control and Prevention warned that residents should “spend time outdoors” and “make relocating to permanent housing a priority.” Even in more expensive new homes, the concentration of emissions from things like furniture, carpet and paint can be two to fi ve times as high as it is outdoors. But most air fi lters only catch particulates such as dust and pollen rather than organic compounds like formaldehyde and benzene, and the fi lters that do trap those gases need frequent replacement. So Mathieu LeHanneur and David Edwards built an ultra-effi cient fi ltration system that eliminates toxins using nature’s own hazmat squad: plants.

The duo, a French product designer and a Harvard University biomedical engineer, unearthed NASA research from the 1980s on plants that absorb chemicals through their leaves and roots. Philodendra, for instance, soak up formaldehyde uch as they do carbon dioxide. But plants can clean only he air that touches them. To quickly and effi ciently clean a hole room, LeHanneur constructed a container that moves s much air as possible around the entire plant. A fan blows reezes around the leaves, and a second fan sucks air through hole in the soil. Microbes on the plant’s roots metabolize ore toxins than the leaves do, nd the soil works like a traditional charcoal fi lter to capture even more. Underneath the soil, a tray of water produces humidity that keeps the plant moist and traps additional toxic molecules. A vent on the side releases fresh air into the room. In early trials, the device reduced a test chamber’s formaldehyde concentration by 80 percent in one hour.

LeHanneur and Edwards built the Bel-Air for an exhibit at Le Laboratoire, a gallery in Paris that features collaborations between scientists and artists. The next step could be pairing with a company to adjust the design for manufacturing. Michael Braungart, an environmental chemist at the University of Lüneberg in Germany, says it’s a creative application of real science: “It uses the best of nature combined with the best that human beings can do.”

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