Wendy Gordon, General Manager, National Geographic's TheGreenGuide.com
A new friend (whose wife just had a baby) was recently telling me about all the things they were doing to keep environmental contaminants out of their home. He asked me if I knew which houseplants were most effective at reducing indoor air pollutants. I didn't know the answer off-hand but was curious to find out.
I came upon a wonderful book by Dr. B.C. Wolverton, How to Grow Fresh Air. What I learned is, while plants can't cure major indoor pollution problems on their own, as noted in a recent Tip of the Week, they are an ideal antidote to the minor contamination introduced into our indoor environments through everyday household products and building materials.
Plants produce oxygen, add precious moisture and remove toxins from the air through the tiny openings in their leaves. In fact, as few as 15 houseplants in an average-size home can offer a significant reduction in the number of indoor contaminants.
This is not just folklore. In the 70s, the National Aeronautics and Space Administration, faced with the task of creating a life-support system for planned moon bases, began extensive studies on a fundamental question -- just how does the earth produce and sustain clean air? The answer of course is through the living processes of plants. Now, 30-plus years later, we know a great deal about the cleansing power of house plants. And powerful they are. Just consider the indoor air quality problems many commonly available and beautiful houseplants can help to remedy:
Formaldehyde: The Boston fern (Nephrolepi exalta "Bostoniensis"), Florist's mums (Chrysanthemum morifolium), the Gerbera daisy (Gerbera jamesonii) and the Dwarf date palm (Phoenix roebelenii) are all highly effective at reducing indoor levels of formaldehyde, a contaminant present in many household items (including particleboard, carpet backings, some grocery bags, facial tissues, paper towels and permanent-press clothing) and released by gas stoves.
Toluene/Xylene: Add an Areca palm (Chrysalidocarpus lutescens), the Moth orchid (Phalenopsis) and the Dwarf date palm to your indoor greenery, all of which are effective at removing xylene and toluene, harmful volatile organic chemicals which can be emitted from gasoline, adhesives, ceiling tiles, computer screens, paints, inks used in photocopiers, stains and varnishes, and upholstery among other common household products and materials.
And it's not just our material things. Our breath contains bioeffluents -- such as ethyl alcohol, acetone, methyl alcohol and ethyl acetate -- that also contribute to poor indoor air quality, particularly in a crowded classroom. The beautiful peace lily is remarkably effective at addressing these problems.
Other hardworking and beautiful indoor plants include bamboo palm (Chamaedorea), Chinese evergreen (Aglaonema), English Ivy (Hedera helix), the indoor dracaenas (Dracaena "Janet Craig," D. marginata, D. massangeana and D. warnekii), and the snake plant or mother-in-law's tongue (Sansevieria trifasciata laurentii).
When choosing houseplants, remember that many (including some of those above) can be toxic if ingested, so be extra careful if you have young children or pets in your home. Staff at the local garden center should be able to advise you on nontoxic choices; contact your local poison-control center for guidance (the phone number is listed in the front of your telephone book).
For a beautiful and authoritative reference to the cleansing power of particular houseplants, order How to Grow Fresh Air (Penguin Books, 1996, $18) from our online book store. And get more tips and advice on how to reduce or eliminate indoor air pollutants in your home at thegreen.guide.com.