Those of us who work in office buildings are hermetically sealed in. It’s a fact not thought about; that’s why we have HVAC. After the OPEC crisis of ’73 and the ensuing push for energy efficiency, American businesses and homes began the practice of sealing off indoor environments in order to conserve the energy necessary to keep them comfortable. The trade off was fresh air.
Enter NASA. The authority on living in enclosed spaces, NASA had been researching the transpiration and chemical absorption rates of certain plants in order to create a hospitable environment for humans who might not have the luxury of cracking a window to let in the breeze. Fast forward a decade or two and you’ll see these plants are incredibly common in offices and public spaces, and there’s a reason for that–based on this study, we know that they are some of the best for maintaining indoor environmental air quality. (Applied science benefits society again–and we dared to defund NASA!)
Add to stale air the increasing number of preservative chemicals, cleaners, and volatile organics that off-gas from our everyday synthetic materials and you’ll get an understanding of how poor indoor air quality can get (and possibly how lousy the air you’re breathing right now is). No matter how outdoorsy we are, we always eventually come back under the roof for a bit.
Being a shameless science nerd I’d always kept plants and animals; the process of growth simply fascinated me, and the added health benefit of oxygen from my plants was a plus, though a seemingly quixotic one. When I came across a TED talk about the quantity of houseplants necessary to support a human being in an enclosed space, I was interested. Because of course I had been obsessed with terrariums as a kid, so the idea of a human in one still appealed to me as an adult (which is not that far from most of our office buildings).
This had also piqued my interest because I had just moved into a basement apartment, which was a bit stuffy, and my irrational fear of a raccoon assault kept me from opening the windows for extended periods of time.
As it turns out, many of the plants with beneficial qualities are also very easy to care for. The trade off is that you’ll have to shake the fear that your living space is beginning to look like a dentist’s office, but when you consider the health benefits, it shouldn’t be too hard.
Topping my list of priorities was straight oxygen, which means plants with the highest transpiration rate. The video mentions a few all-stars–Areca Palm, Mother-in-Law Tongue (or Snake Plant), and Moneyplant–for various reasons, and rightfully so.
- Areca palms are incredible transpirators, earning the top rating in the NASA study, and also earning an 8/10 for the removal of chemical vapors from the air.
- Mother-in-law’s tongue is not a great gas-exchanger, oddly, but does have the unusual characteristic of oxygen expulsion at night, which as Mr. Meattle points out, makes it a great bedroom plant. It will also withstand a stunning amount of neglect.
- Money plant (though the picture looks more like golden pothos) is good at removing chemical vapors from the air, which given what I’ve learned about off gassing since starting this, seems increasingly important.
How to Grow Fresh Air lists 50 plants that topped the study, and offers information on each, citing transpiration rates, ease of care, resistance to insect infestation, and chemical absorption, all on a convenient 1-10 scale.
Based on the information in the book, my top three were easily:
- Bamboo Palm, which nearly tops the charts at a 9/10 rating for transpiration and removal of chemicals, followed by a 8/10 for ease of maintenance and resistance to infestation.
- Boston Fern, which boasts the same 9/10 scores for respiration and chemical absorption as does the bamboo palm, though it is not as easily maintained.
- English Ivy for its 9/10 chemical absorption rate and it’s 7/10 respiration.
Though you may have never heard of these plants, you’ve definitely seen them. While the species from this study and “How to Grow…” are certainly beneficial, you’ll by no means be traveling to secluded valleys in China to secure cuttings from rare oxygen-spewing plants. For better of for worse, they’re are all plants you’ve seen around (but may not have appreciated), and while their aesthetic may not be a conversation starter in your home, perhaps their fascinating biological processes will be.
Interested in learning more about improving your indoor air quality? Pick up a copy of “How to Grow Fresh Air” and see which plants appeal most to your needs. Also, try heading to your local nursery; if you’re in Seattle, try Swanson’s-they have a knowledgeable staff and a good selection of species and prices. And as always, feel free to email with questions/suggestions~