How pure is the air you breathe? Plants are the lungs of the earth: they produce the oxygen that makes life possible, add precious moisture, and filter toxins. Houseplants can perform these essential functions in your home or office with the same efficiency as a rainforest in our biosphere. In research designed to create a breathable environment for a NASA lunar habitat, noted scientist Dr. B.C. Wolverton discovered that houseplants are the best filters...