By Jesse Eastman
For years and years there has been a popular understanding that adding houseplants to your home will help remove toxins from the air, add oxygen, and generally improve air quality. Even one plant, it was claimed, could help you breathe easier. This study, titled ”Interior Landscape Plants for Indoor Air Pollution Abatement” was performed in 1989 by BC Wolverton (https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930073077.pdf). It showed that plants could in fact improve air quality by removing benzene, trichloroethylene, and formaldehyde from the air. Rejoice!
More recently, this study has come under scrutiny, or rather, the popular response to this study has been reevaluated. The National Geographic recently published an article (https://www.nationalgeographic.com/science/2019/11/houseplants-dont-purify-indoor-air/) looking at the hard data uncovered in Wolverton’s study and concluded that realistically, houseplants are doing little to remove toxic compounds from our homes. Basically, the 1989 study was done under tightly controlled settings that simply do not exist in our homes. Our homes exchange air at such a high rate compared to the small sealed chambers in which Wolverton’s experiments were done that one plant, or even a ton of plants, just simply can’t make a measurable difference. In fact, a small apartment of only 500 square feet would need around 5,000 plants to meaningfully impact air quality.
So what are we to make of this? Should we bemoan the fact that houseplants aren’t, in fact, cleaning our air effectively? Does this mean houseplants are nothing more than needy pieces of art with which we adorn our shelves and window sills? I say nay!
I’m actually glad for the research showing the relative inefficiency of plants at cleaning air. Any time we can pull back the curtain on incorrect beliefs, we move forward as a species. If indoor volatile compounds are a concern (and I believe they absolutely are), we now know we can’t rely on our pothos and ferns, and must take other steps such as opening windows to allow fresh air in or installing in-home air purification systems. We are safer for the knowledge.
Furthermore, this doesn’t mean houseplants are suddenly nothing more than needy green paperweights. While they may not be of good value as air cleaners, they still hold tremendous value and importance for what they do for our mental wellbeing. I see it every day when customers walk into our greenhouse. They step into the lush humid environment, frowns relax, shoulders loosen. Their eyes brighten and they take a deep breath, exhaling worries and stress.
I think I speak for all of us when I say we take a lot of pride in our plants. If you are fortunate enough to have a knack for exotic and hard-to-grow varieties, they can become a badge of honor, your identity. They add color and life to our home. By creatively combining the right plant with the right pot, they can provide an artistic outlet that is utterly unique. For many of us, they even provide an agreeable conversation partner, sometimes the most intelligent one around!
So we have to dispense with the pleasant notion that houseplants will protect us from volatile compounds. So what? They are no less special for it. Although I suppose if you really want to cling to that 30 year old study, I won’t be the one to stop you from packing thousands upon thousands of plants into your home!
Originally published on February 4th, 2020.