With a new plant-powered personal air filter, the French industrial designer Mathieu Lehanneur and a Harvard scientist named David Edwards have found a way to improve upon Mother Nature herself. Their Bel-Air filter, which combats indoor emissions from paint and plastics, sucks air into a humid Pyrex bulb containing a plant. The air circulates among the leaves, and then the filter forces it out through the plant’s roots, where, according to Lehanneur, microorganisms collect and metabolize toxic compounds. “The same plant, under normal conditions, will not filter like this,” he says. “We force the air to follow an ideal path.” The low-volt device isn’t yet ready for consumers, but can be observed at “Design and the Elastic Mind” at New York’s Museum of Modern Art this spring.