The Andrea, $200, claims to "harness the power of nature to create clean air for your family." Its clear, fan-equipped casing holds a plant, and polluted air is supposed to pass across the leaves and root system and be released as purified air into the room. The box boasts, "If it's good enough for Mother Nature, shouldn't it be good enough for your family?" The prototype was good enough to earn Popular Science's Invention Award, which called it "an ultra-efficient filtration system that eliminates toxins using nature's own Hazmat squad: plants." And the stylish design was displayed at the Museum of Modern Art.
Our tests, using a recommended spider plant, found that the Andrea won't help remove dust, pollen, or smoke. And volatile organic compounds? We checked with the lead author of a study cited on the Andrea website. That study included a prototype of a purifier that used a potted plant. The test chamber used in the study was a 16x12-foot room with 10-foot ceilings. In that space it would take four Andrea-type purifiers to have a significant effect on formaldehyde, a common VOC, explained Jianshun S. Zhang, Ph.D., professor and director of energy and indoor environmental systems at Syracuse University. "The potted-plant purifier we tested in that study actually did not perform well," he added. "They are misrepresenting my study."
In a room with ample ventilation, Zhang said, you could forgo the purifier and just keep some well-watered plants.