Indoor Air Defense
As temperatures drop and we close our windows, my thoughts turn to indoor air quality. I don't know about you, but having the windows closed all the time is really hard for me. Here in Western North Carolina, our outdoor air quality is pretty darn good (most days). But what happens when we shut the windows? What about that stuff inside the house?
All homes can suffer a decrease in indoor air quality when we close up our homes for winter. Our methods of heating our homes can contribute to this problem, but we can just as easily be victimized by off-gassing from pressed-wood product furniture, carpeting, cleaning products or other things outside our control such as radon. Delightfully, it is fairly easy to give ourselves a first line of defense against these airborne assaults on our health. All you need is a little green.
Green in the form of: houseplants! This is not new news, but sometimes it helps to remember how these friends can be of benefit. First, let's start with the psychological. Studies suggest that "people . . . recover faster from illness in the presence of plants." [NASA Spinoff] Plants in office settings reduce "flu-like symptoms." Behavioral "boredom" signals are reduced by 70% when plants are present in classrooms or lecture halls. Even views out a window where greenery is evident can speed the healing process or improve academic achievement. [See Native Backyard link, below.] These results aren't because of something we inhale around plants--it's just the fact that they are there. Our psyches know we need them, even if we don't. Want to boost productivity? Introduce houseplants at work! One large plant for every two people will get you the psychological benefits. Just make sure there is at least one in every space used for work.
Now let's leave the psychological and get into the measurable science. Houseplants reduce blood pressure. This is probably a result of the psyche, but the impact is physical. They have a huge impact on indoor air toxins--removing volatile organic compounds (VOCs). "The most successful plants, Peace Lily and English Ivy, removed 80% of the Benzene inside a sealed chamber." [NASA's Plant Scores] Since toxins like Benzene, Trichloroethylene and Formaldehyde--which are highly prevalent in traditional home and office spaces--can be essentially neutralized by a prescription of houseplants, it would behoove those who prefer to forgo the respiratory and nervous system risks to take two Boston Ferns (Nephrolepis -- drought tolerant!) before popping any pills.
Much of what we know now is based on work by Bill Wolverton, who was funded by the Space Center to look into Sick Building Syndrome. NASA was a little worried about sending their astronauts off into long-term housing (so to speak) that could suffer from the same problem as tightly sealed office buildings. Unlike folks at the office, the astronauts wouldn't exactly be able to open a window. Wolverton's research identified a good 50 plants that excelled at scrubbing indoor air.
The following list, taken from the last source listed, not only gives you names but the individual plant "best defense against" comments (which have been abbreviated for clarity). Note that anything with a reputation for being bug resistant might be poisonous to pets or small children.
Areca Palm: 8.5 Natural humidifier
Lady Palm: 8.5 Bug resistant and easy to grow
Bamboo Palm: 8.4 Second best at air purifying
Rubber Plant: 8.0
Removes formaldehyde and requires minimal light
Dracaena: 7.8 A leader at removing formaldehyde
English Ivy: 7.8 Best allergy reducer
Dwarf Date Palm: 7.8 Trichloroethylene remover
Ficus Alii: 7.7 Easy to maintain.
Boston Fern: 7.5 Most efficient at removing formaldehyde and benzene
Peace Lily: 7.5 Second best at removing benzene. Needs plenty of water.
Other standouts include Philodendron, Chlorophytum comosum (spider plant) and Sansevieria (snake plant). Plants do not have to be huge. A six to eight-inch pot is sufficient to generate good vibes, but a light potting soil mix is essential. The air scrubbing is a function of the roots, so healthy roots in an airy soil mixture will yield the greatest health benefits. If you have pets (particularly dogs--less discriminate in their eating habits), be sure to check the ASPCA link under those recommended to verify if a given plant might be toxic if ingested.
Bottom line? If you don't have houseplants--get some. Hardest to kill--I'd have to go with the snake plant. They love to be crowded in a pot and take very little water. Meaning you can go away for days at a time and ignore it, and it will love you anyway. As long as you water it when you get back. Easiest to propagate? My vote goes to philodendron or to spider plant. Buy one philodendron and you're set for life. Give one to someone you love!