In the natural world, plants perform the crucial duty of filtering dirty air from the atmosphere. French designer Mathieu Lehanneur mimics that natural process with Andrea, a slick-looking home air purifier powered by plants. The air cleaning tech draws air in through a quiet fan before propelling it through the leaves and root system of the plant, and then out through the soil and back into the room. Indoor air doesn't get much fresher than that. And you can use any kind of household plant that fits in the pod.