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It seems like every workplace has that one person who swears that the potted spider plant sitting on their desk has an almost magical ability to purify the air in the office. Are they actually onto something?

There is evidence to show that plants can remove pollutants from indoor air. But a single potted plant probably won’t go the distance. If you’ve heard that bringing plants into your home or office will improve your indoor air quality, you probably have a study conducted back in 1989 by NASA to thank for that meme.

The goal was to test whether a variety of types of indoor plants could be used for air purification, both on Earth and in space. The plants were put into sealed containers, and the air pumped full of chemicals including benzene and formaldehyde. Those chemicals fall under the broader umbrella of volatile organic compounds, or VOCs.

Some VOCs are known to cause health issues like headaches or liver and kidney damage. And they’re noteworthy as indoor pollutants because household products and building materials can give them off. The plants were kept under controlled conditions, with plenty of light and water and the air quality was measured over a 24 hour period.

The study found the majority of the plants included in the experiment removed much of the benzene and formaldehyde from the containers. Plants are thought to remove pollutants from the surrounding air by absorbing the gases through their leaves and roots with some possible help from the microorganisms in the soil. So that's it, right?

Houseplants help clean the air? Well, not quite. Later studies doing similar experiments have yielded mixed results.

A 2009 study tested 28 varieties of indoor plants and found four that were best at capturing every VOC the researchers threw at them. So plants definitely can remove some pollutants in a laboratory test chamber. But these idealized lab conditions don’t exactly represent the air in your office -- stuff like the amounts of light, water, and air circulation are all going to be different.

On top of that, the lab plants were purifying the air in a small area. Some of the chambers in the NASA study were less than a cubic meter in volume. That means for the same amount of purification to happen in your house, you would need an indoor rainforest.

One critic of the NASA study suggested that to get the same effect in a typical home you’d need about 680 separate plants. There have been a handful of other studies investigating the effects of plants on indoor air quality, but at least one review, published in 2014, has attempted to take stock of the existing research. And it concluded that, while lab-based studies generally show some effect, not many have been performed in living spaces, and the ones that have been done haven’t yielded a consensus.

So don’t count on your poor desk fern to fix all of your indoor air problems. Thanks for watching this episode of SciShow, and thanks to Emma Hulton for asking. To find out how to maybe get your questions answered, head over to patreon.com/scishow. [ outro ].