With so many people staying home these days, it makes sense that there’s increased interest in healthy living spaces.
That’s led people to renew their interest in houseplants, both for décor and as a way to purify their homes of cancer-causing chemicals. After all, a much-touted study from NASA stated that indoor plants effectively reduce indoor air pollutants.
But like so many things, there’s a lot more to the story…
If you look back over the past ten years or so, retailers and writers alike have made a huge deal out of the superpowers of plants when it comes to removing toxins, dangerous chemicals, and volatile organic compounds (VOCs) from the air. Indeed, plant sales over the past three years have topped $1.7 billion in the United States.
The truth about NASA’s Clean Air study
Part of what led to this craze was the aforementioned 1989 Clean Air study from NASA that stated certain plants are able to filter toxins from the air, including benzene, trichloroethylene, carbon monoxide, ammonia, formaldehyde, and styrene. You don’t need a degree in chemistry to know you do NOT want the items on this list in your air.
Helpful plants include the rubber tree, Chinese evergreen, Boston fern, and spider plant, to name just a few. The golden pothos, weeping fig, bamboo palm, and the peace lily are also high on the list for their ability to filter out specific toxins.
The good news is, these plants do filter toxins. But the problem is that in the NASA study, plants were in airtight chambers only slightly larger than two by two feet. And yes, those plants did cut down on the VOCs researchers circulated around them using a small fan. But this is a trivial amount of space compared to a whole house or even one room.
What’s more those conditions do not mimic a typical household environment, where the types and levels of toxins vary based on household activity, and where the area is not airtight.
A modest contribution to clean air
The truth, according to an article published last year in the Journal of Exposure Science & Environmental Epidemiology, found that plants don’t have nearly the kinds of powers we’d like them to have – at least in terms of indoor air filtration.
Yes, it is true that potted plants have demonstrated the ability to remove VOCs from the air. But this is only true in those small, sealed chambers over a time lapse of many hours or days.
In contrast, an average-sized potted plant in an average-sized home makes very little difference. Though it will remove VOCs from the air, it will happen at such a slow rate there’s no competition between plants and the air exchange mechanisms already in place in most buildings.
In fact, researchers found that it would actually take up to 93 plants per square foot of floor space to perform as much air filtration as an office ventilation system. In a 500-square-foot apartment, that means 5,000 plants—you’d have no room for anything else!
A problem at epidemic levels
So I guess on this I’ll give two cheers for technology, even if I’m a nature lover. And you’d best avail yourself of whatever technology you can to clean the air in your dwelling. Indoor air pollution is a serious problem, especially when you’re trying to keep your body free of toxins that can cause cancer to grow or return.
According to the Environmental Protection Agency, a growing body of evidence shows the air in our homes can be much more polluted than outdoor air, and shockingly, that’s true even when compared with the biggest and most industrialized cities.
Sources of indoor air pollution include heating oil, gas, kerosene, coal, wood, and building materials. Household cleaners and personal care products only add to the problem.
On top of all that, outdoor sources such as radon, pesticides, and car exhaust are also prevalent. Polluted air from those sources finds its way into houses, sometimes through obvious openings like doors and windows, and sometimes through joints or cracks in the walls, floors, and ceilings.
Modern day science improves upon plants
But don’t get too down on plants yet, because thanks to technology an interesting twist is starting to emerge. Scientists at the University of Washington have begun experimenting with genetically modified plants that can better remove VOCs from the air.
Environmental engineer Stuart Strand and his research team started by taking a protein found in mammalian livers and genetically modifying it to be placed in a common pothos ivy. They coded the plants with this protein (sourced from rabbits), and found that the genetically modified ivy removed chloroform and benzene from the air at a higher rate than non-modified ivy.
I have to admit this scenario has a touch of Frankenstein to it – even though I’m not as freaked out by genetically modified plants as some people are.
But after all, we wouldn’t be eating these plants. Maybe it can all be done safely. In any case they’re still a long way from developing plants that will clean the air in a large space.
Do plants still belong in a home?
Plants are nice to have around. They boost your mood and make your space more attractive. They serve as natural humidifiers and bring life into a home, potentially inspiring creativity as well as focus.
All of these benefits can lead to improved mental health, which is important in cultivating the motivation we need to do things like eat well, exercise, and stay socially connected.
But if clean air is your principal aim, spend your time and money on air purifiers and toxin-free cleaners and personal care products.
Unless, of course, you can manage caring for a few thousand houseplants in your living space. If that’s the case, by all means – go for it!
- “Interior Landscape Plants for Indoor Air Pollution Abatement.” By Wolverton, B., et al, 15 September 1989. https://ntrs.nasa.gov/citations/19930073077
- “The Inside Story: A Guide to Indoor Air Quality.” Retrieved 14 December 2020 from the EPA site: Indoor Air Quality. https://www.epa.gov/indoor-air-quality-iaq/inside-story-guide-indoor-air-quality
- “15 Air-Purifying Plants to Cleanse Your Space of Chemicals and Toxins.” By Kristi Kellogg, 6 July 2020. https://www.architecturaldigest.com/gallery/best-air-purifying-plants
- “Which houseplants should you buy to purify air? None of them.” By Sarah Gibbens, 14 November 2019. https://www.nationalgeographic.com/science/2019/11/houseplants-dont-purify-indoor-air/
- “10 best air purifying plants for the home.” By Samantha Prattey, Apr 11, 2019.
- “Houseplants do not clean the air in our homes, new study reveals.” By Lisa Walden
Nov 11, 2019. https://www.countryliving.com/uk/homes-interiors/interiors/a29754853/house-plants-air-quality-study/