Natural Home - Air Exchange

In the depths of winter I finally learned that within me there lay an invincible summer. - Albert Camus 1913 - 1960

Whether you offer them a sumptious victorian conservatory or a narrow window-ledge, houseplants can help you breath easier. Indoor air is polluted from the various fibers present in most consumer and commercial grade carpet, clothing and decorative fabrics and wall coverings, solvents found in wallboard, paints, varnishes and furniture at home and at work. People who suffer from "sick building syndrome" often find some relief when plants are present.

In 1980 scientists at the John C. Stennis Space Center in southern Mississippi found that plants can purify air. It turns out a number of plants are pretty good at absorbing volatile organic compounds (VOCs), translocating the chemicals to their roots and breaking them down.

A worthy deed, since formaldehyde and numerous other VOCs are a natural byproduct of many of the ingredients of modern life--plywood, particleboard, carpeting, synthetic fabrics and plastics, to name the most common.

High on the good-plant list: areca palm, lady palm, rubber plant, English ivy, Boston fern. The spider plant, which has often been linked with air-purifying properties wasn't quite as efficient.

VOCs are emitted as gases from certain solids or liquids. One of the factors influencing VOC-removal rate has to do with the rate of transpiration--that is, how much water evaporates from a plant's leaves. As the plant absorbs water through its roots, air is pulled into the root zone, where microorganisms facilitate the breaking down of the chemicals into sources of food and energy.

The best air-cleaning plants can remove 1,000 to 1,800 micrograms of VOC per hour but that equates to less than two milligrams of bad stuff.

Can people actually tell the difference?

A Norwegian study found that office workers whose spaces had plants reported 23 percent fewer complaints of fatigue, stuffy noses, coughing and eye irritation than workers who had no plants nearby. No doubt helping alleviate discomfort was the fact that plants also increase the humidity level of a room to a more comfortable 30 to 60 percent.

OP Hints:

• Plants aren't a panacea. You can't offset the effect of polyurethane with even two dozen areca palms. Plants, no matter how many you have or what kind, are no substitute for good ventilation and more important, eliminating or reducing the source of the pollution whenever possible.
• Plants aren't powerful vacuum cleaners that suck contaminants from across a large room. Put them near where you spend a lot of time--by your computer, in the kitchen, beside a comfortable chair.
• Over-watering or a continuously damp soil surface leads to the production of mold spores. Place an inert material such as pea gravel on the surface of your potted plants or use a hydroponic (growing in water, not soil) system. Keep your houseplants as vigorous as possible. The healthier they are, the better job they'll do at reducing air pollutants.

Great Green Air Cleaners

Note: Some plants--such as golden pothos, dieffenbachia, some philodendrons and dracaenas, and peace lily--can be toxic to dogs; depending on the variety of plant and the size and weight of the dog, effects can range from mild oral irritation to poisoning. If you have a dog that likes to nibble, place these plants out of reach.