Do Houseplants Actually Filter Your Air?

Plants are pretty wonderful, providing us with food, shade, and breathable air, but they aren’t magical. Yes, rainforests are vital for our ecosystem because they filter carbon out of the air and create oxygen — but any notion that houseplants can be used to filter toxins out of the air in our homes is, as this report in The Atlantic indicates, wishful nonsense. Here’s why you should buy plants as decoration or to promote personal wellness — but not to serve as an air purifier.

Why house plants can’t filter your air effectively

In nature, plants indeed keep our ecosystem healthy by oxygenating the air serving as a carbon sink, and even absorbing some pollutants, but the effect doesn’t exactly scale down — according to the informational site Science Alert, to actually filter toxins out of the air effectively you would need, “between 10 and 1,000 [plants] for every square metre of your living space.” Unless you live inside of a greenhouse, that’s not exactly a realistic option.

This idea that plants filter and purify air in a confined space was popularised in the 1980s, when NASA scientist Bill Wolverton conducted a study on the ability of certain house plants to remove volatile organic compounds from the air in a closed environment. This discovery was designed with an eye toward astronauts who live in sealed compartments for extended periods of time, but is now often misused as evidence for why you should buy more plants to scatter around your home. As engineering professor Dr. Michael Waring told The Atlantic, the results of the 1989 study do not apply to the average household:

“Wolverton measured whether houseplants could remove VOCs from an airtight laboratory environment. But a home is not a hermetic chamber. It has open windows and doors, drafts and leaks, and much more clutter.”

If you are a scientist or astronaut stuck in an airtight chamber for hours, it might be a good idea to bring a plant or two along with you. If you’re worried about fresh air in your home, open a window.

You should still keep plants around for many other reasons

Instead of buying specific plants with the erroneous hope they’ll clean up your air, buy them for the psychological and emotional benefits they confer. According to Healthline, living in a plant-filled home can help lower stress levels and increase productivity. Not only does the smell of plants like peppermint or lavender create a more relaxing environment, the business of caring for plants can improve your mood. CNBC reported on a Japanese study that found full-time desk employees who took breaks to tend to their plants showed decreased pulse rates and anxiety levels.

Of course, some of the sites touting plants’ abilities to help us destress are also the ones promoting using plants to improve air quality. And while there’s certainly nothing wrong with filling your home with greenery and flowers, just remember: Plants are great, but they aren’t magic — so buy a pansy and an air purifier.