July 23, 2026
The most popular "air-purifying" houseplants — snake plant, spider plant, peace lily, pothos, and the palms and ferns below — earned that label from NASA's 1989 sealed-chamber experiments. Here's the honest version most lists skip: in a real, ventilated room, the air-cleaning effect of a few potted plants is very small. Peer-reviewed research puts hard numbers on it. So grow them for the greenery, the calm, and the humidity they add — and pair them with filtration to actually capture particles. Below: 12 most popular and an additional 22 plants with light, water, care, and ASPCA pet-safety for each, then what the science really shows.
Here is the straight answer: houseplants barely clean your air. They do absorb VOCs, but a 2019 Drexel University review of 196 experiments found your ordinary household ventilation clears those compounds faster than plants can. You would need roughly 680 plants in a 1,500 sq ft home to keep up. Filterbuy builds air filters for a living, so we know how that sounds coming from us; every source is linked, check us. Keep the plants for how they look. Just know that eight of the twelve everyone recommends are toxic to pets.
A 2019 review in the Journal of Exposure Science & Environmental Epidemiology concluded that potted plants do not improve indoor air quality, after analysing 196 experiments.
The American Lung Association’s published position is that houseplants do not clean indoor air.
Only 4 of the 12 most-recommended air-purifying plants are non-toxic to cats and dogs per the ASPCA: spider plant, Boston fern, areca palm, bamboo palm. Snake plant and aloe vera, the usual bedroom picks, are both toxic.
NASA’s 1989 study was co-funded by a houseplant trade association and tested "the most common houseplants in the industry." NASA published that history.
NASA’s report recommends an activated carbon filter with a fan. The scientist who ran it later patented one, reporting roughly 200x the performance of a potted plant.
Ventilation and mechanical filtration are what actually move indoor air quality. Plants are a decorative layer on top.
Mostly no, not at any scale that matters in a real room. Houseplants do absorb VOCs like formaldehyde and benzene through their leaves and root-zone microbes. That part is real. The problem is rate. In 2019, Drexel University researchers Bryan Cummings and Michael Waring reviewed 196 experiments from 12 published studies and found that normal air exchange in a home dilutes VOCs far faster than plants can remove them. Their paper is titled, without much ambiguity, "Potted plants do not improve indoor air quality."
The American Lung Association puts the requirement at 10 to 1,000 plants per square meter, or roughly 680 plants in a 1,500 sq ft home. Their own advice is source control, ventilation and a MERV 13 filter. Filterbuy sells air filters and the honest answer happens to favour us. We would rather say so than let you buy a peace lily expecting it to do a furnace filter’s job.
What plants do: absorb trace VOCs far too slowly to matter, raise local humidity, and make a room feel better, which has a better evidence base than the air chemistry. What they do not do: remove particulates. Dust, pollen, dander, smoke and PM2.5 pass straight by. That is what a filter is for.
These are the twelve houseplants most commonly recommended for air purification, every species checked against the ASPCA plant database. Only four are non-toxic to cats and dogs, and the snake plant and aloe vera, both routine bedroom picks, are toxic. On calling them the "best": they are the twelve on every list, ranked by criteria that do not survive contact with a real room. Read it as the twelve most-recommended, checked properly.
Pet-toxicity status verified against the ASPCA Toxic & Non-Toxic Plant Database, [PLACEHOLDER: verification date]. "Toxic" means ingestion can cause a reaction, most commonly vomiting, drooling, or GI upset. It does not mean the plant is lethal. Toxic species are fine in homes without pets, or placed genuinely out of reach. ASPCA Animal Poison Control: (888) 426-4435.
If you have an animal that chews, the four green rows are your list. The advice to put a snake plant in your bedroom is worth flagging: the ASPCA lists it as toxic, and the bedroom is where your cat sleeps.
Room choice should follow light and who lives there, not air chemistry, because the difference between species at room scale rounds to zero.
Bedroom: spider plant if you have pets, snake plant only if you do not. On the "releases oxygen at night" claim: snake plant and aloe are CAM plants and do open their stomata at night. Peace lilies and spider plants are C3 and do not, despite what most lists say. Either way the oxygen involved is a rounding error against a room.
Bathroom: Boston fern. Non-toxic and it genuinely likes the humidity. One honest caveat: the American Lung Association lists ferns among plants that can worsen allergy symptoms.
Living room: areca or bamboo palm for a pet-safe room with presence. Rubber plant or peace lily if there are no animals.
Nursery: spider plant, Boston fern, areca palm or bamboo palm, and nothing else on this list. A crawling child and a toxic plant are a bad pairing regardless of how it scored in a sealed chamber in 1989.
Kitchen and office: aloe vera on a sunny windowsill in pet-free homes; bamboo palm or corn plant under fluorescent light. Your kitchen VOC load comes mostly from cooking, and a vented range hood beats any plant.
NASA’s 1989 Clean Air Study is real and has been misread for thirty-five years. Led by B.C. Wolverton, it placed 12 species in sealed chambers, dosed them with formaldehyde, benzene and trichloroethylene, and measured what remained after 24 hours. Between 10% and 70% was removed. The purpose was life support for sealed space stations, not living rooms.
The chamber is the whole story. It has almost no air exchange; your home replaces its entire air volume every one to three hours. In a chamber the plant is the only thing removing VOCs. In your bedroom it is competing with ventilation, and losing.
And NASA’s report does not conclude that you should buy houseplants. It concludes that you should buy a carbon filter with a fan in it. Figure 1 of the report is an engineering diagram of a golden pothos sitting on an activated carbon bed with a squirrel-cage fan pulling air through it. The summary states that activated carbon filters with fans should be considered an integral part of any plan using houseplants. The industry kept the plant and deleted the machine.
One more thing buried in the tables. NASA tested plants with full foliage, then cut every leaf off and retested the same pots. Golden pothos removed 67.2% of benzene intact and 64.6% with no leaves at all. The report credits the root-soil zone and its bacteria. The air-purifying plant is mostly a pot of dirt.
Filterbuy has manufactured activated carbon air filters in our own American factories since we sold our first filter in 2013, in Alabama, Florida, Pennsylvania and Utah. Carbon media that adsorbs gases, bonded to a pleated filter that catches particles, with the fan in your HVAC system pulling air through it.
Look at that Figure 1 diagram again. A bed of activated carbon. A fan. A pothos on top. Minus the pothos, that is the thing Filterbuy makes. We built it for over a decade without connecting it to the houseplant study, because like everyone else we had only seen the list. We opened the report for this article. The filter is on page 3.
We are not claiming NASA endorsed Filterbuy. The claim is narrower: the study everyone cites as proof that houseplants clean air is, structurally, a design document for a carbon filter. We noticed because we build the machine.
"We sell air filters, so when I tell you a snake plant isn’t going to clean your bedroom, I get the eye-roll. Fair. So don’t take my word for it, go read NASA’s actual report. It’s 22 pages, and the thing they recommend is a carbon filter with a fan in it. That’s on page 3. I’d rather hand you the source than ask you to trust me."
• Michelle Wan, Brand Manager and Air Quality Writer, Filterbuy
The houseplant industry co-funded it, and chose the plants. NASA published a history of the research in 2012, written by Dr Gary Stutte of Kennedy Space Center. It states that the interior plantscape industry approached Wolverton for funding, and that the Associated Landscape Contractors of America then approached Stennis Space Center about jointly funding a two-year study of, in NASA’s words, the most common houseplants in the industry. That funding is disclosed on the 1989 report’s inside cover, where it has sat for thirty-five years.
The release was a publicity campaign. The report launched at a National Press Club press conference timed to "Plants for Clean Air Day" on Capitol Hill, and a non-profit, the Plants for Clean Air Council, was founded to promote houseplants nationally. Wolverton was its scientific spokesperson. All of that is NASA’s own account.
This does not make the science fraudulent. Wolverton was a serious scientist and industry funding does not invalidate a result. What it means is narrower: a conflict of interest exists, and it has never been disclosed to you. Every listicle opening with "NASA proved houseplants clean your air" is quoting a study a houseplant trade association helped pay for, using that association’s own product list. Filterbuy is aware of the irony of a filter manufacturer raising this, which is why our conflict is disclosed at the top of this page and at the bottom. One of these conflicts is on the label.
Wolverton retired from NASA in 1990 and patented an air purifier that forces air through a plant’s root zone using high-efficiency carbon filters, sold as the EcoPlanter in Japan. NASA’s history gives the number: it removes approximately 200 times more VOCs than a single traditionally potted plant.
That is the man who ran the famous study telling you what a potted plant is worth. His answer was a fan, a root-zone airflow path and a carbon filter: the same three components in Figure 1, and the same three in the Filterbuy Odor Eliminator we have made since 2013. Wolverton and Filterbuy arrive at the same place from opposite directions. The same NASA history notes plants work best in non-ventilated buildings, which is the entire 2019 debunk, conceded in NASA’s archive seventeen years early.
Nobody appears to have checked this, and it takes one line of arithmetic. NASA’s Table 3 lists how much formaldehyde each plant removed. In the column immediately to its left, it lists each plant’s total leaf surface area. Those areas vary by roughly 20x. The famous ranking uses the first column and ignores the second, so we divided one by the other.
Our arithmetic on NASA's published figures. Micrograms removed and leaf surface area both come from NASA-TM-101766, Table 3; the fourth column is the first divided by the second. Six of 14 species shown. Leaf area varied roughly 20x across the study, which is why the two rankings disagree.
The bamboo palm is NASA’s number one because it is enormous, carrying fourteen times more leaf than the English ivy in the next chamber. And the peace lily, sold for three decades as NASA’s star performer and called exactly that on the previous version of this page, finishes dead last. The list is not telling you which species cleans air better. It is largely telling you which pot was bigger on the day. Buying the number-one plant does not buy better chemistry, it buys more leaves. So buy two of the cheaper one, or the one you like the look of.
The most-repeated statistic in this topic is a high-school science fair project. Every page tells you English ivy removes 78% of airborne mold in 12 hours, credited to "research from the American College of Allergy, Asthma & Immunology." We went looking for the paper. There is not one.
Source: Kim, R. & Spyers-Duran, H. (2005), abstract presented at the American College of Allergy, Asthma & Immunology annual meeting, Anaheim, CA. Conference abstract; not peer-reviewed.
None of this makes the teenager wrong. It was a decent project and it measured what it measured: a sealed container with moldy bread in it. It is not evidence that ivy will touch the mold in your bathroom, and it should never have become the load-bearing citation for an entire content category. If you have mold, you have a moisture problem. The EPA is blunt about it: the key to mold control is moisture control.
These are not competing options. They act on different pollutants at wildly different rates.
The order of operations: fix the moisture, open a window, upgrade the filter, then buy the plant because you like it. Filterbuy would rather tell you to open a window, which costs nothing and outperforms everything here, than sell you something that will not help. The filter is step three, not step one. See MERV ratings, activated carbon air filters for the gases plants are wrongly credited with, and indoor air quality metrics to measure any of it. On a bad air day, close the windows and let the filter work.
Look up the botanical name, not the common name. "Rubber plant" covers at least four unrelated species with different toxicity. Ficus elastica is toxic; Peperomia obtusifolia is not.
Assume "out of reach" fails for cats. A high shelf is not a control measure for a determined animal. Most plants here cause vomiting rather than organ failure, but that is still a vet visit.
Save the number. ASPCA Animal Poison Control: (888) 426-4435. A consultation fee may apply.
Three numbers underpin this page, all from US government or nonprofit primary sources, checked July 16, 2026.
All three sources verified live on July 16, 2026. ASPCA figures are for calendar year 2024, the most recent full year published. EPA ventilation page last updated April 29, 2026; EPA mold page last updated February 18, 2026.
Air exchange rate (ACH): how many times per hour a room’s air volume is replaced with outside air. A typical home runs 0.35 to 1 ACH. This is the number that overwhelms plant-based VOC removal.
ASPCA: the American Society for the Prevention of Cruelty to Animals, whose Toxic & Non-Toxic Plant Database is the standard reference US veterinarians use.
CAM (Crassulacean acid metabolism): a photosynthetic pathway in which a plant opens its stomata at night rather than by day. Snake plant, aloe vera and many orchids are CAM. Peace lilies and spider plants are not.
Cummings & Waring (2019): Drexel University researchers whose 2019 review concluded that potted plants do not improve indoor air quality.
Filterbuy: an American air filter manufacturer, founded 2013, making pleated and activated carbon HVAC filters in its own factories in Alabama, Florida, Pennsylvania and Utah. Filterbuy published this page and sells the filtration it recommends, which is why the conflict is disclosed throughout.
MERV: Minimum Efficiency Reporting Value, the 1 to 16 scale rating an HVAC filter’s particle capture. MERV 8 catches dust and pollen; MERV 13 catches PM2.5 and smoke.
NASA Clean Air Study: a 1989 study led by B.C. Wolverton at NASA’s Stennis Space Center measuring VOC removal by 12 houseplant species in sealed chambers. Origin of the air-purifying plant claim.
VOC: volatile organic compound, a carbon-based chemical that evaporates at room temperature. Sources include paint, cleaning products and furniture off-gassing. The EPA reports indoor concentrations run 2 to 5 times higher than outdoors.
Not at any meaningful scale in a real room. A 2019 Drexel University review of 196 experiments found household ventilation removes VOCs faster than plants can. You would need roughly 680 plants in a 1,500 sq ft home to match the air exchange you already have.
Most are not. Of the 12 most-recommended, only four are non-toxic per the ASPCA: spider plant, Boston fern, areca palm and bamboo palm. Snake plant, aloe vera, peace lily, pothos, English ivy, rubber plant, corn plant and philodendron are all toxic. Check the botanical name before buying.
Yes. The ASPCA lists Dracaena trifasciata, formerly Sansevieria trifasciata, as toxic to both dogs and cats. It contains saponins, causing nausea, vomiting and diarrhea. This matters because it is the most commonly recommended bedroom plant, and bedrooms are where pets sleep.
That figure comes from a high-school science fair project presented as a conference abstract in 2005, using moldy bread and dog feces in sealed containers. It was never peer-reviewed or replicated. Mold is a moisture problem.
No, and they are not substitutes. Plants do not touch particulates at all. For whole-home coverage an HVAC filter outperforms both a plant and a single-room portable purifier. Filterbuy makes pleated filters from MERV 8 to MERV 13 plus an activated carbon line for gases and odors, which is the category plants are wrongly credited with covering.
Cummings, B.E. & Waring, M.S. (2019). "Potted plants do not improve indoor air quality." Journal of Exposure Science & Environmental Epidemiology.
Wolverton, B.C., Johnson, A. & Bounds, K. (1989). Interior Landscape Plants for Indoor Air Pollution Abatement. NASA-TM-101766.
Stutte, G.W. (2012). Phytoremediation of Indoor Air: NASA, Bill Wolverton, and the Development of an Industry. NASA Kennedy Space Center, NTRS 20120003454.
American Lung Association. "Actually, Houseplants Don’t Clean the Air." · ASPCA Toxic & Non-Toxic Plant Database. · US EPA, Mold and Health; How much ventilation do I need in my home?
Kim, R. & Spyers-Duran, H. (2005). English ivy particulate reduction. Abstract, ACAAI annual meeting. Not peer-reviewed.
Disclosure: Filterbuy manufactures and sells HVAC air filters. This page concludes that mechanical filtration outperforms houseplants, which aligns with what we sell. We have cited the primary research so you can check it yourself.
