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The Air We Breathe — Indoor Foliage

While discussions on air pollution are typically centered on cheery topics like smog, acid rain and CFCs, studies conducted on home air quality in the late 1980s suggest that the impurities floating around our indoor spaces could be just as harmful. The happy news is that indoor air pollution is something we can directly impact on without protesting in a pith helmet or chaining yourself to a tree.

The Study

A two-year study conducted by NASA and the Associated Landscape Contractors of America (ALCA) uncovered a sophisticated apparatus adept in soaking up harmful pollutants: the common houseplant. Typically of tropical origin, indoor plants grow in the shady understory of tropical forests. This means they flourish in low light and must be exceedingly efficient at processing the necessary gases for photosynthesis. This renders them well-suited to indoor environments and capable of removing harmful chemicals from the air.[/one_half_last]

Dr. Bill Wolverton, former senior research scientist at NASA’s John. C. Stennis Space Centre in Mississippi, has spent several years conducting research into using organic processes to solve environmental problems. Based on initial evaluations of the use of common indoor plants for indoor air cleansing, ALCA joined NASA to fund a study which used around a dozen well-known species of plants to ascertain their helpfulness in eliminating a number of pollutants associated with indoor air contamination. Research results strongly suggested that living plants are super efficient at absorbing pollutants in the air—so  much so that some will even be launched into space as part of the biological life support system aboard future orbiting space stations. While more research is necessary, Wolverton says: “We feel that future results will provide an even stronger argument that common indoor landscaping plants can be a very effective part of a system used to provide pollution free homes and work places.”

During the study, each plant was placed in sealed, Plexiglas chambers into which chemicals were injected. These bad boys included the following:

  • Trichloroethylene (TCE): found in a wide variety of industrial uses, including metal degreasing and dry cleaning companies, as well as in printing inks, paints, lacquers, varnishes, and adhesives.
  • Benzene: a very commonly used solvent that can be found lurking in regular household items like gasoline, inks, oils, paints, plastics, and rubber. Benzene is also used in the manufacture of detergents, pharmaceuticals, and dyes, and has been linked to what is now known as Sick Building Syndrome (SBS).
  • Formaldehyde: present in virtually every indoor environment, formaldehyde can be found in products like tobacco smoke, manufactured wood products like particleboard and plywood used in cabinets and furniture, durable-press drapes and other permanent-press fabrics, adhesives, cleaning products, fire retardants, water repellents, wrinkle resistors and stiffeners. Formaldehyde is also used in grocery bags, waxed papers, facial tissues and paper towels. Other sources of formaldehyde include heating and cooking fuels like natural gas, kerosene, and cigarette smoke.

Study results uncovered that the philodendron, the spider plant and the golden pothos were labeled the most effectual in removing formaldehyde molecules. Flowering plants such as gerbera daisy and chrysanthemums came top of the heap in removing benzene from the atmosphere. Other top performers included dracaena and spathiphyllum.

Wolverton explains: “Plants take substances out of the air through the tiny openings in their leaves, but research in our laboratories has determined that plant leaves, roots and soil bacteria are all important in removing trace levels of toxic vapors. Combining nature with technology can increase the effectiveness of plants in removing air pollutants. A living air cleaner is created by combining activated carbon and a fan with a potted plant. The roots of the plant grow right in the carbon and slowly degrade the chemicals absorbed there.”

Top of the Crops

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The good news for us is that many of the plants listed by NASA as the most effective pollutant absorbers are available at your local BVI nursery. Here’s a quick look at what should be on your landscaping nursery shopping:

  • Areca Palm – Dypsis lutescens (among the most effective at oxygenating small, enclosed areas, making them great for the office)
  • Bamboo Palm – Chamaedorea seifritzii
  • Boston Fern – Nephrolepis exaltata
  • Dwarf Pygmy Palm – Phoenix roebellini
  • Golden Pothos – Epipremnum aureum
  • Janet Craig – Dracaena “Janet Craig”
  • Lady Palm – Rhapis Excelsa (also noted for its ability to absorb ammonia)
  • Peace Lily – Spathiphyllum
  • Rubber Plant – Ficus elastic
  • Weeping Fig – Ficus benjamina
  • Mother-in-Law’s Tongue – Sansevieria laurentii (most effective at producing oxygen at night, so perfect for the bedroom)
  • Red-Edged Dracaena – Dracaena marginata

And last but not least, an unlikely suspect – sprouts. Growing plants for food inside your home has a mini-green house effect, and a variety of sprouts, such as those used in salads and Asian dishes, along with herbs produce oxygen and possess air-cleaning qualities. Plus, they’re a great addition to your culinary accomplishments.

It is important to remember that although all the above are not high maintenance creatures, they do require adequate light, soil, drainage and water. The recommended number of plants for an average size home of less than 2,000 square feet is about 15 to 18 plants of the varieties that improve the air quality. To be effective, each plant needs to be large enough to be potted in a six-inch or more diameter pot. This also allows the root structure to grow and expand.

John Muir, Scottish-born American naturalist, author, and early advocate of wilderness preservation in the United States, once said that when one tugs at a single thing in nature, he finds it attached to the rest of the world. And he’s right. Every choice we make – no matter how small – has an impact. With this in mind, I think it’s pretty clear where I’ll be spending the first Saturday of Earth Month. I hope to see you there.

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