NASA and the Associated Landscape Contractors of America's "Clean Air Study" concludes that indoor plants provides a natural way of removing toxic agents from the air and thereby neutralizing the effects of sick building syndrome.
Indoor plants not only produce oxygen but can also absorb contaminants such as benzene and formaldehyde (known carcinogen), and trichloroethylene. NASA researchers suggest one plant per 100 square feet of home or office space can provide efficient air cleaning.
Plants can "filter" a room reducing 50-60 % airborne microbes (such as mold spores and bacteria), according to Dr. B.C. Wolverton's research.