Does Monstera Clean the Air? What the NASA Study Actually Proved
NASA’s 1989 study didn’t include monstera — and its lab results don’t apply to real homes. Here’s what the science actually says about monstera and indoor air quality.
You have probably seen the claim dozens of times: NASA proved that houseplants — including monstera — remove toxins from indoor air. It is one of those facts that spreads because it sounds exactly right. Plants are natural. Air quality is a real concern. And monstera’s enormous, tropical leaves look like they should be doing something impressive.
The reality is more nuanced — and in one key respect, more interesting. The 1989 NASA study is real, its results are real, but the version of it circulating on the internet omits several critical details that change its meaning entirely. Monstera itself was not even in the study. And the conditions under which the plants performed so impressively have essentially nothing in common with a furnished, ventilated American home.
This article explains exactly what the NASA study proved, what it didn’t, and what monstera genuinely contributes to your indoor environment. The honest picture is less dramatic — but it is grounded in evidence, and it points toward benefits that are real, practical, and worth having.
What the NASA Clean Air Study Actually Proved
Here is the version of events you will find on most plant websites: NASA conducted a study proving that certain houseplants — including monstera — remove toxins from indoor air, making your home measurably cleaner. It is a compelling story, and it has been repeated so many times that most people accept it without question.
The problem is that it is only partially true — and the part that gets monstera wrong is the most important part.
The original 1989 NASA study, formally titled A Study of Interior Landscape Plants for Indoor Air Pollution Abatement and conducted by researcher B.C. Wolverton in collaboration with the Associated Landscape Contractors of America, tested twelve specific plant species. Monstera deliciosa was not among them. The plants that were tested included snake plant, English ivy, peace lily, Chinese evergreen, bamboo palm, weeping fig, and several varieties of dracaena. Monstera was nowhere in the data.
That single fact undermines a large share of what you will read online about monstera and air purification. The claims are not based on direct research — they are assumptions, drawn by analogy from plants that were actually studied.
So what did the NASA study genuinely prove? In sealed, one-cubic-meter plexiglass chambers — about the size of a small chest freezer — individual plants were exposed to concentrated doses of formaldehyde, benzene, and trichloroethylene. After 24 hours, researchers measured how much of each chemical remained. In many cases, the reduction was dramatic: up to 90% of the injected VOC was gone.
Those results are real. The question is what they mean for your living room.
The Gap Between a Sealed Chamber and Your Living Room
A sealed 1 m³ chamber is nothing like a home. It has no windows, no doors, no air conditioning, no ventilation system, and no human activity generating fresh VOC sources. A single concentrated chemical is injected once, and the plant has 24 uninterrupted hours to work on it. These are conditions specifically designed to detect the maximum possible effect.
In 2019, researchers Bryan Cummings and Michael Waring at Drexel University published a systematic analysis of 12 chamber studies covering 196 experimental results. Their goal was to translate the lab findings into a metric that means something in a real building — the clean air delivery rate, or CADR, the same standardized measure used to evaluate mechanical air purifiers.
The median CADR for a single potted plant was 0.023 m³/h.
For context, a typical US home has a natural air exchange rate of approximately 1 h⁻¹, meaning a standard room replaces its air volume roughly once per hour through infiltration, ventilation, and normal household activity. To match that passive dilution using only plants, you would need between 10 and 1,000 plants per square meter of floor space.
In a 1,500-square-foot home, the American Lung Association estimates that comes to approximately 680 plants.
Researcher Michael Waring told reporters after the paper published: plants are great, but they do not actually clean indoor air quickly enough to have an effect on the air quality of your home or office environment. The mechanism by which plants absorb VOCs — stomatal uptake and rhizosphere microbial breakdown — is real, but it operates too slowly to compete with the ventilation your home already provides.
VOC Removal Rates: What the Lab Data Actually Shows
The table below summarizes controlled-study data on VOC removal for specific houseplants. All figures come from sealed chamber experiments unless marked with an asterisk — conditions that cannot be replicated in a ventilated home.
| Plant | VOC Tested | Lab Removal | Time / Conditions |
|---|---|---|---|
| Peace lily | Benzene | Up to 75% | 1 m³ sealed chamber, 24 h |
| Snake plant | Formaldehyde | Up to 60% | 1 m³ sealed chamber, 24 h |
| Pothos | Formaldehyde | 81–96% | Hydroponic system, 24 h |
| English ivy | Formaldehyde | ~99.99% | Sterilized media, 67.6 h |
| Dracaena | Benzene | 46–54% | Sealed chamber, 72 h |
| Areca palm | Total VOC | 88.16%* | Real-world conditions, 4 months |
| Monstera | — | No controlled data | Not included in 1989 study |
*Areca palm is the only entry derived from real-world conditions rather than a sealed chamber. All others reflect performance under laboratory conditions that do not transfer to ventilated homes.
Does Monstera Actually Clean the Air?
The absence of direct research does not mean the answer is definitively no. Monstera is a large-leafed tropical plant with substantial stomatal surface area. Like most foliage plants, it almost certainly absorbs trace amounts of airborne VOCs through its leaves and delivers them to soil microbes in the rhizosphere for breakdown. The mechanism is real; the scale is the problem.
Botanically, monstera is similar to species like pothos and philodendron that have been studied — and those plants do show VOC absorption in lab conditions. It is reasonable to assume monstera does too. What the Drexel analysis makes clear is that this absorption is too slow to matter in any room with functional ventilation. If you sealed a small room, ran no HVAC, and filled it wall-to-wall with mature monsteras, you would probably detect a reduction in VOCs over 24 hours. That scenario is not your home.
The fair verdict: monstera probably absorbs trace VOCs like most other leafy houseplants. That rate is too low to constitute meaningful air purification in any real-world living space. Claims to the contrary are extrapolating beyond what the evidence supports — and most of those claims incorrectly attribute NASA’s 1989 findings to a plant that was not in the study.
The mechanism by which plants process VOCs adds a nuance worth understanding. Most VOC breakdown happens not in the leaves but in the rhizosphere — the biologically dense zone surrounding the root system. Soil microbes, sustained by carbon compounds exuded from plant roots, metabolize VOC molecules that have migrated through the soil or been transported internally from the leaf surface. Research has consistently found that the same plant species removes more VOCs in active soil than in sterile media, meaning the microbial community does more of the actual chemical work than the plant’s own tissue. For a houseplant owner, this has a practical implication: a monstera in a large pot with rich, well-aerated soil has more genuine VOC-processing potential than the same plant in a small pot with compacted or depleted growing medium. Heavy-handed fungicide applications also reduce whatever modest benefit the rhizosphere contributes.
What Monstera Actually Delivers for Your Indoor Environment
Correcting the myth is not the end of the story. Monstera genuinely improves your indoor environment in ways that are well-supported by evidence. They are just different benefits than most people expect.
It Raises Humidity — and That Matters
Transpiration is the process by which plants release water vapor through their stomata. Large-leafed tropical plants like monstera are vigorous transpirators, and this has a measurable effect on indoor humidity.
A 2024 study published in PLOS ONE measured relative humidity across three offices at different plant densities. With no plants, median relative humidity was 29.1%. With five Boston ferns, it rose to 38.9%. With eighteen plants, it reached 49.2% — a statistically significant increase attributed directly to plant transpiration.
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→ Build Watering ScheduleWhy does this matter? Centrally heated US homes in winter routinely drop below 30% relative humidity — a level that dries out mucous membranes, increases susceptibility to respiratory viruses, and creates the itchy throat and dry skin that become seasonal constants. Research published in Frontiers in Molecular Biosciences found that maintaining indoor humidity between 40% and 60% is associated with reduced viral transmission.
A single monstera will not transform your whole-home humidity. But three or four mature plants in a bedroom, combined with other strategies, contribute meaningfully to reaching that target range. That is a real, quantifiable benefit — and one that a HEPA air purifier does not provide.
The Psychological Benefit Is Solid Science
The stress-reduction evidence for indoor plants is more robust than the air-purification evidence, yet it receives far less attention.
A 2015 randomized crossover study published in the Journal of Physiological Anthropology had 24 participants alternate between transplanting indoor plants and performing computer work. The results were measurable and significant: diastolic blood pressure dropped from 71.75 mmHg during computer tasks to 65.26 mmHg during plant interaction (p = 0.001). Sympathetic nervous system activity — the physiological signature of stress — was significantly lower during plant tasks (p = 0.021). Participants reported feeling more comfortable, soothed, and calm.
These are not self-reported feelings. They show up in heart rate variability and blood pressure readings. The mechanism is likely biophilic: humans evolved in natural environments, and visual and tactile contact with vegetation triggers a measurable relaxation response. Monstera’s large, dramatic foliage — particularly its characteristic fenestrated leaves as it matures — makes it effective in this role.
Passive Dust and Particle Capture
Monstera’s broad leaves also act as passive particle traps. Airborne particulate matter — dust, pet dander, pollen — settles onto leaf surfaces and is removed from circulation until you wipe the leaves clean. The effect is minor relative to a HEPA filter, but it is mechanically genuine and contributes to allergen load reduction in the immediate area around the plant.
What Actually Reduces VOCs in Your Home
If plants are not the primary solution, what is? The EPA’s approach to indoor VOC reduction is built on a principle that every air quality researcher agrees on: source control beats filtration every time.
Choose low-emission products. New furniture, carpet, and flooring off-gas formaldehyde and other VOCs most intensely in the first six to twelve months. When replacing these items, look for CARB Phase 2 compliant or GREENGUARD Gold certified products. This eliminates the source rather than trying to capture emissions after the fact.
Ventilate strategically. Opening windows for 10–15 minutes in the morning flushes accumulated overnight emissions before cooking, cleaning, or any activity that generates additional VOCs. The EPA notes that indoor VOC concentrations can spike to 1,000 times outdoor background levels during certain activities — ventilation is the fastest and cheapest way to reduce them.
Upgrade your HVAC filters. Standard 1-inch HVAC filters do not capture fine particulates. MERV 13 filters remove particles down to 0.3 microns, covering smoke, pollen, dust mite debris, and some biological contaminants. Replace every 60–90 days for continuous effectiveness.
Add a HEPA air purifier in high-traffic rooms. A quality HEPA unit removes 99.97% of airborne particulates. For VOCs specifically, look for a unit with an activated carbon stage — carbon adsorption is the actual VOC-capture mechanism that plants approximate too slowly to compete with.
Store VOC-emitting products outside. Paints, solvents, adhesives, and cleaning products should be stored in a garage or outdoor shed, not under kitchen sinks or in utility closets inside the home.
Plants fit into this picture as a supplementary layer — not a replacement for any of the above. A home with good ventilation, MERV 13 filtration, and a few well-cared-for monsteras will have better air quality than the same home with ventilation alone. The monstera contributes; it just does not lead.
Getting the Most From Your Monstera’s Genuine Benefits
Since monstera’s real contributions are humidity, psychological effect, and passive particle capture, here is how to maximize each:
Keep leaves clean. A dust-coated leaf captures particles but cannot release water vapor as efficiently — stomata partially blocked by dust operate below capacity. Wipe leaves with a damp cloth monthly, more often in dry winter months when central heating runs continuously. Avoid commercial leaf-shine sprays, which coat the stomata and reduce transpiration. Cleaning monstera leaves is one of the most underrated care steps for keeping the plant performing well.
Provide bright indirect light. A monstera receiving adequate light transpires more and produces larger leaves. Monstera light needs are moderate — 6 or more hours of bright indirect light is the target. Plants in low light grow slowly, transpire less, and contribute less to room humidity.
Water correctly. A well-hydrated monstera transpires significantly more than a drought-stressed one. Check the top 2–3 inches of soil; water thoroughly when dry, then allow the pot to drain completely before returning it to its saucer. In winter, reduce frequency as growth slows.
Provide a climbing support. In its native Central American habitat, monstera climbs tall trees and produces leaves that can exceed 24 inches across. A moss pole encourages the same growth pattern indoors — larger leaves mean more stomatal surface area, more transpiration, and more passive particle trapping. A climbing monstera is a more effective humidifier than one left to sprawl.
Cluster plants for compounding benefits. One monstera raises local humidity marginally. Three or four in the same room have a compounding effect — shared microclimate, elevated ambient humidity, and amplified biophilic visual impact. If humidity is the goal, grouping is the most efficient single change you can make.
Frequently Asked Questions
Was monstera actually in the NASA Clean Air Study?
No. The 1989 Wolverton study tested twelve plant species, and monstera deliciosa was not among them. The species tested included snake plant, English ivy, peace lily, bamboo palm, Chinese evergreen, weeping fig, Barberton daisy, florist’s chrysanthemum, and several dracaena varieties. Any source claiming NASA proved monstera cleans air is either misremembering the study or extrapolating from it without disclosure.
How many monsteras would I need to actually clean a room?
A 2020 analysis by Drexel University researchers found that a single plant has a CADR of 0.023 m³/h. A typical 150 sq ft bedroom cycles roughly 37 m³ of air per hour through natural ventilation. To match that ventilation rate using plants alone, you would need more than 1,600 plants in a single bedroom. This is not a viable air purification strategy — it is a useful illustration of why ventilation is the actual workhorse of indoor air quality.
Is monstera good for a bedroom?
Yes — for the right reasons. It contributes to humidity in dry heated bedrooms, provides a documented biophilic calming effect, and its large leaves trap some particulates passively. Keep it away from direct drafts from vents, provide adequate indirect light during daytime hours, and let it climb for best results.
What houseplant is best for air purification?
No houseplant makes a meaningful dent in VOC levels in a ventilated home. If air purification is the primary goal, a HEPA filter with activated carbon outperforms any plant by orders of magnitude. For humidity and biophilic benefits, high-transpiration species perform best: areca palm, Boston fern, and spider plant have the strongest evidence. Monstera excels for psychological and aesthetic value. For a comparison of the best air-purifying houseplants, the combination of species matters more than any single plant.
Is monstera toxic to pets?
Yes. Monstera deliciosa contains insoluble calcium oxalate crystals that cause oral irritation, excessive drooling, and difficulty swallowing if chewed by cats or dogs. Keep it out of reach of pets and small children. If ingestion occurs, contact your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435.
Does monstera produce oxygen at night?
No more than other foliage plants, and the contribution is small. Like most houseplants, monstera photosynthesizes during daylight hours, absorbing CO₂ and releasing oxygen. At night it respires, reversing the process slightly. In a typical bedroom, the CO₂ exhaled by sleeping adults dwarfs any plant-related oxygen contribution. The oxygen benefit is real but not meaningful at the scale of a single houseplant in a normally ventilated room.
Sources
8. American Lung Association. Actually, Houseplants Don’t Clean the Air. Published February 14, 2024.
