The knowledge that houseplants can improve indoor air quality was discovered in the early 1980s, when NASA (National Aeronautics and Space Administration) was faced with the task of creating a life-support system for planned moonbases. They began extensive studies on treating and recycling air and wastewater and this led to the discovery that houseplants could remove formaldehyde from the air in the sealed test-chambers. The results of these studies were published in 1984. There then followed two years of further research with the Associated Landscape Contractors of America to further evaluate the ability of twelve common houseplants to remove formaldehyde, benzene and trichloroethylene from sealed chambers. Their positive results were published in late1989 and led to the formation of the Plants for Clean Air Council (USA), a non-profit organization that continues to support the cultivation of plants as a method of improving indoor air quality.    ......more