7 Best Air-Purifying Houseplants According to NASA (and What the Research Actually Says)
Houseplants do more than just beautify your home. As it turns out, they can improve your health, too! See the list.
Quick Reference: Air-Purifying Plants
- The 7 plants: snake plant, spider plant, pothos, peace lily, English ivy, areca palm, philodendron.
- What the NASA 1989 study found: these plants removed VOCs (formaldehyde, benzene, trichloroethylene) in sealed chambers.
- What later research found: the effect in real homes (open spaces, normal ventilation) is much smaller. You would need 100+ plants for measurable improvement.
- Real benefits: humidity, aesthetics, mental wellbeing. The air-purification effect in normal homes is modest.
- Tool: the Almanac’s easiest container plants.
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Sources cited in this guide
The famous NASA Clean Air Study from 1989 found that common houseplants removed harmful VOCs from sealed test chambers. The study spread widely and became one of the most-cited reasons to add houseplants to homes and offices. The honest follow-up: later research from Drexel University and others found that in real homes with normal ventilation, the air-purification effect is much smaller than the original study suggested. This guide is the 7 best NASA-tested plants, the real research, and the honest reasons to grow them.
What the NASA Study Actually Did (and What It Did Not)
Per NASA’s 1989 Clean Air Study documentation and Drexel University’s follow-up research.
- The setup. Plants placed in sealed chambers (refrigerator-sized) and exposed to specific VOCs.
- The finding. Plants did absorb measurable amounts of formaldehyde, benzene, trichloroethylene, and other VOCs in those sealed chambers.
- What it did not test. Plant performance in normal-sized homes with normal ventilation. The chamber was 700+ times more concentrated and sealed.
- Drexel 2019 follow-up. Calculated that in a typical home, removing meaningful VOCs would require 100+ plants per room, far more than anyone keeps.
- The honest takeaway. The plants do work in principle. The effect in normal homes is modest. Ventilation and avoiding VOC sources matter much more.
Air-Purifying Houseplants (Detail)
Below are the original 7 detail sections plus notes on other toxins houseplants remove.
7 Best Air-Purifying House Plants
1. Mums. The plant with the most purifying power is the Chrysanthemum morifolium, or the potted mum, that you can find at garden centers and grocery stores in the fall. While mostly a fall outdoor plant, you can bring them in when the weather gets cold. And you’re going to want to! During NASA’s tests, these beauties cleaned up 61% of the formaldehyde, 53% of the benzene and 41.2% of the trichloroethylene, all while sending up a profusion of colorful blooms.
2. Gerbera Daisies. Gerbera daisies are another colorful flower that packs a purifying punch. In 24 hours, this flower removed half of the airborne formaldehyde, 67% of the benzene and 35% of the trichloroethylene.
3. Peace Lilies. Among all the plants in this study, the peace lily is one of the most popular. The Clean Air Study showed that in one day, peace lilies can remove up to a quarter of some airborne toxins. The benzene test, however, is where these plants really stood out, sucking up an amazing 79.5% of this toxin.
4. Dracaena. It turns out that the dracaena family is really good at air purification, particularly when it comes to benzene. The Marginata variety, or red-edged dracaena, is one of the best, removing up to 80% of this toxin from the air. Janet Craig, a green dracaena, removes 77.6% of benzene, and Warneckei, the striped dracaena, works well against benzene and formaldehyde, removing half of both toxins from the air.
5. English Ivy. If you like trailing plants, then English ivy is a must for your houseplant collection. It was the top plant at benzene removal, taking care of 90% of the toxin within 24 hours, and it also removed small amounts of other toxins as well.
6. Snake Plant. It goes by a number of names, St. George’s sword, mother-in-law’s tongue or simply sansevieria, but it’s easily recognizable by the long, stiff leaves edged in yellow. This plant removes 52.6% of airborne benzene along with a substantial amount of formaldehyde.
7. Ficus. A staple plant in homes and offices, ficus trees are great at toxin removal. During NASA’s tests, these trees cleaned up 47.4% of the airborne formaldehyde they were exposed to along with 30% of the benzene and 10.5% of trichloroethylene.
The plants listed above are some of the best at removing airborne toxins, but they’re by no means the only houseplants that will get the job done. Most plants will absorb toxins to some degree, and the NASA study also found that with continued exposure over a period of six weeks, houseplants doubled their capacity to clean up the air.
Other Toxins Houseplants Remove
Furthermore, benzene, formaldehyde and trichloroethylene aren’t the only toxins that plants will remove. They’ll take care of a wide range of pollutants found in smoke, solvents, finishes and household chemicals. What’s more, the plants aren’t the only things that reduce pollution levels. The potting soil helps, too. The NASA study found that leaving the soil exposed so that there was room for air to circulate between the plant’s lowest leaves and the soil line increased toxin absorption by 15%.
If you’ve ever kept houseplants, then you know that caring for them can be good for the soul; the NASA Clean Air Study proves that they’re good for your health, too.
Air-Purifying Plants FAQ
Do houseplants really clean the air?
Yes in principle, modestly in practice. NASA’s 1989 study showed measurable VOC removal in sealed test chambers. But Drexel University’s 2019 follow-up calculated that in a normal home you would need 100+ plants per room to match the air cleaning provided by simple ventilation. Houseplants are good for humidity, aesthetics, and mood; air purification is modest.
What is the best air-purifying houseplant?
Per the NASA Clean Air Study, snake plant (Sansevieria), spider plant (Chlorophytum), and golden pothos (Epipremnum aureum) topped the list for VOC removal. These three are also among the easiest houseplants to grow and tolerate low light.
How many plants do you need to clean the air in a room?
Per Drexel University research, on the order of 10 to 100+ plants per room would be needed to provide air cleaning comparable to simple ventilation in a typical home. Most homes have far fewer. Plants help, but ventilation matters much more for indoor air quality.
Are NASA-recommended plants safe for pets?
Several are not. English ivy, peace lily, pothos, and philodendron are all toxic to cats and dogs (mild to moderate). Spider plant and areca palm are non-toxic. Always check ASPCA’s pet plant database before bringing home a new houseplant if you have pets.
Do air-purifying plants remove dust?
Modestly. Large-leafed houseplants (philodendron, peace lily) collect some dust on their leaves and serve as natural air filters in that mechanical sense. Wiping the leaves periodically helps. The effect is small compared to a HEPA filter.
Amber Kanuckel
Amber Kanuckel is a freelance writer from rural Ohio who loves all things outdoors. She specializes in home, garden, environmental, and green living topics.
- Amber Kanuckel
- Amber Kanuckel
- Amber Kanuckel
- Amber Kanuckel
I’m wondering if there is a time better to transplant house plant from small pots or starts to a bigger pot? such as my aloe plants , they have outgrown the pot
Jan 15-16, 2023 would be good dates to transplant. Happy to hear your Aloe is thriving!
Many more do exist furnish
I have an indoor art studio and put my snake plant in it because of the windows but I have noticed that it is growing like crazy could it be the toxins from the materials that I am using?
Do the toxins help the plants grow?
Stephaine, I hope there aren’t too many toxins in your studio not only for the plant’s sake but yours! Perhaps the lighting is good or it just likes it in there?
I’m wondering if there is a time better to transplant house plant from small pots or starts to a bigger pot?
Hi Edith, Each plant has its own “rules” when it comes to transplanting. For example, you shouldn’t transplant Christmas cacti when they are blooming. Let us know which ones you’re looking to transplant.
I live in a townhouse but my windowsill are not wide enough to out plants on.what would you suggest?
Hanging plants work well. Amazon has a system that hooks to ceiling with 4 shelves suspended on wires that’s really cool, but pricey.
Get a grow light. Amazon has nice ones two feet long that are only fifty dollars. My herbs love it
ALL plants give oxygen and ‘ingest’ carbon dioxide; so all plants would be good in helping to add oxygen to your home while reducing the carbon dioxide. Many will also help keep dust down.
That NASA ‘study’ was done, first, in the 1980’s and their list was much longer. Some plants (many plants) will remove even more; like harmful gases formaldehyde, trichloroethylene and other noxious Indoor gases you’d breathe.
One plant for about every 10 x 10 (100 sq ft) area will do it. A variety of plants works best and for those with black thumbs try a few low light plants in low light areas and high light plants in sunny windows. – don’t forget to ware them and dust their leaves once in a while.
Thank you for the information…it gets pretty stuffy in the summer with the A/C running constantly in AZ…we appreciate the wholesome information!
LOVE Farmer’s Almanac!! Does anyone know if a lemon plant cleans the air at all?? Thanks!
I’m looking fwd to reading this piece.
Unfortunately, many houseplants are toxic to pets if ingested. Peace lilies — and most other lilies — are definitely toxic. On this list, Gerbera daisies should be safe. Palms, zebra plants and African violets are all safe, too. Here’s a page from the ASPCA that lets you search by toxic and non-toxic plants:
http://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants
Also…any plant in the cactus/succulent family has a substance that will make your pets “high” if they chew on them or injest…had this experience with a hose cat and Christmas cactus!! It was amusing but probably not safe!