The Famous 1989 NASA Study
It all began with a study from 1989, when NASA, in partnership with the Associated Landscape Contractors of America, looked for ways to clean the air in sealed environments like space stations. The goal was to see if common houseplants could remove volatile
organic compounds (VOCs) from the air. VOCs are chemicals like formaldehyde, benzene, and trichloroethylene that can be released from everyday items like furniture, carpets, cleaning products, and paints. Researchers placed various plants in small, sealed chambers and injected these chemicals to see how much the plants could absorb over a 24-hour period.
What Did the Research Find?
The results were promising. The study found that, under these controlled laboratory conditions, certain plants were indeed effective at removing significant amounts of the targeted VOCs from the sealed chambers. For example, some plants removed a high percentage of benzene and formaldehyde. The process, known as phytoremediation, involves the plant absorbing these pollutants through its leaves and the microorganisms in its soil breaking them down. This is the core finding that launched the idea of "air-purifying" plants into popular culture. The study identified several effective plants, including the Peace Lily, Snake Plant, and Spider Plant, which remain popular choices today.
The Catch: From Sealed Chamber to Living Room
Here’s where we need to manage expectations. The NASA study was conducted in a small, sealed container, which is very different from the average home or office. Our living spaces are much larger and are not airtight. They have constant air exchange from windows, doors, and ventilation systems, which dilutes pollutants much faster than a few plants can. More recent analyses have concluded that you would need an enormous number of plants—some estimates suggest hundreds in a single room—to meaningfully replicate the air-cleaning effects seen in the lab. While plants do remove pollutants, their effect in a typical room is quite small compared to simple ventilation.
So, Should You Ditch Your Plants?
Absolutely not! While they may not be the miracle air purifiers they're sometimes claimed to be, houseplants offer a wealth of other proven benefits. Being around greenery is known to reduce stress, lower blood pressure, and improve your overall mood. Studies have shown that having plants in your workspace can boost concentration, productivity, and creativity. They also add moisture to the air through transpiration, which can help ease dry skin and respiratory issues, especially in dry winter months. Simply put, plants make our indoor environments more beautiful, calming, and pleasant places to be.
Great Plants to Own Anyway
Even with the new context, the plants highlighted in the NASA study are still fantastic choices for your home, largely because they are hardy, attractive, and easy to care for. Snake Plant (Sansevieria trifasciata): Often called Mother-in-Law's Tongue, this plant is incredibly low-maintenance and tolerates low light. Uniquely, it releases oxygen at night, making it a popular choice for bedrooms. Spider Plant (Chlorophytum comosum): This is a resilient and fast-growing plant that is non-toxic, making it a safe choice for homes with pets. Its arching leaves and baby plantlets make it visually interesting. Peace Lily (Spathiphyllum 'Mauna Loa'): Known for its beautiful white flowers, the Peace Lily is great for lower-light spots and is quite forgiving if you forget to water it, as its leaves will droop to let you know it's thirsty. Areca Palm (Chrysalidocarpus lutescens): This popular indoor palm adds a lush, tropical feel to any room and is effective at adding humidity to the air.
