You have probably seen the claim that certain indoor plants purify the air in your home. It is everywhere: plant shops, lifestyle blogs, and social media posts citing a NASA study as proof. The truth is more complicated, and more interesting, than the marketing suggests.
The best indoor plants for air quality did perform well in laboratory tests. Specific species removed formaldehyde, benzene, and trichloroethylene from sealed glass chambers. But those chambers had no ventilation, no air exchange, and VOC concentrations far higher than any normal room. When researchers looked at what happens in actual buildings, the numbers told a different story.
This guide covers the science honestly. I will walk through what the research found, which air purifying indoor plants tested best, and why you should grow them for reasons that are real rather than reasons that are exaggerated.
Do Indoor Plants Actually Clean the Air?
The short answer: barely, in real-world conditions.
The long answer starts with the NASA Clean Air Study, formally titled “Interior Landscape Plants for Indoor Air Pollution Abatement,” published by B.C. Wolverton in 1989. Wolverton tested 12 common houseplants in sealed glass chambers and measured how much they reduced concentrations of three volatile organic compounds: benzene, formaldehyde, and trichloroethylene. The plants removed between 10% and 70% of these chemicals over 24 hours.
The results were real. The science was sound. The problem is what happened next.
Media coverage stripped away the study’s context. The sealed chambers had zero air exchange. VOC levels were artificially elevated to 1,000+ micrograms per cubic metre, roughly 10 to 100 times higher than a typical home. The chambers were tiny. None of these conditions exist in any building where people actually live.
What the Research Actually Shows
In 2019, Bryan Cummings and Michael Waring at Drexel University published a meta-analysis in the Journal of Exposure Science and Environmental Epidemiology that examined 196 experiments from 12 studies spanning 30 years. Their conclusion was definitive: indoor plants do not meaningfully improve air quality in real buildings.
The key finding comes down to air exchange rates. A typical home or office exchanges its air 0.5 to 1.0 times per hour through normal ventilation (doors, windows, HVAC). That ventilation dilutes VOCs far faster than any plant can absorb them. Cummings and Waring calculated that you would need 100 to 1,000 plants per square metre of floor space to match the cleaning effect of normal air exchange. For my 60-square-metre flat, that is somewhere between 6,000 and 60,000 plants.
The American Lung Association takes a clear position: houseplants do not clean indoor air. Their recommendation is to focus on source control (reducing pollution at its origin), ventilation, and air filtration.
A 2023 study from the University of Technology Sydney found that a green wall system removed 97% of petrol-related VOCs in 8 hours. That sounds impressive, but it tested a dense green wall (not individual pots) in controlled conditions, and the same questions about real-world air exchange apply.
The 8 Best Indoor Plants for Air Quality
If the science is this clear, why list air purifying indoor plants at all? Because the lab results are still interesting. These species genuinely metabolise certain chemicals more effectively than others. They also happen to be excellent houseplants for completely separate reasons: they are attractive, easy to grow, and several tolerate low light conditions well.
I grow all of these in my flat. I keep them because I like them, not because I expect them to replace an air purifier.
1. Peace Lily (Spathiphyllum)
The peace lily tested as one of the strongest performers in the original NASA study. It removed benzene, formaldehyde, and trichloroethylene, with a 23% reduction in trichloroethylene in 24 hours, the highest of any species tested.
Beyond the lab data, peace lilies are genuinely good houseplants. They flower in indoor plants low light conditions (above 200 foot-candles), and the white spathe blooms appear several times a year. Mine sits in my east-facing bedroom and droops dramatically when thirsty, which is actually helpful because it removes the guesswork about watering. Keep the soil evenly moist and use filtered water if your tap water is hard.
2. Spider Plant (Chlorophytum comosum)
Spider plants showed particularly strong results for formaldehyde removal. One study using carbon-14 labelled formaldehyde found spider plants removed 88% of the chemical in 24 hours and metabolically incorporated it into plant tissue, confirming the plant was genuinely breaking down the compound rather than just adsorbing it to surfaces.
They are also among the easiest easy indoor plants to grow. Mine produces trailing stolons with baby plantlets in autumn and winter when daylight hours shorten. They prefer 75-400 foot-candles and handle irregular watering well. Brown tips usually mean fluoride sensitivity from tap water, not a care problem.
3. Golden Pothos (Epipremnum aureum)
Pothos removed benzene, formaldehyde, and trichloroethylene in the NASA trials. Researchers noted that root-zone microorganisms (the bacteria living in the soil) contributed significantly to the removal, meaning the soil itself was doing much of the work.
As a houseplant, pothos is nearly indestructible. It trails from shelves, grows in water, and tolerates light as low as 50 foot-candles. I have one in my living room that I water roughly every 10 days. It looks exactly the same whether I pay attention to it or ignore it for a fortnight. The solid green jade variety handles lower light than variegated types.
4. Snake Plant (Dracaena trifasciata)
Snake plants use crassulacean acid metabolism (CAM), which means they absorb CO2 at night rather than during the day. This made them particularly interesting for the NASA research, which was focused on sealed space station environments where nighttime CO2 management matters.
For home growing, the night-time CO2 absorption is negligible in any room with normal ventilation. What makes snake plants worth growing is their extreme tolerance for neglect. Mine sits in a north-facing room at about 80 foot-candles and gets watered once a month in winter. It grows slowly but looks good year-round. The upright form works well in tight corners where trailing plants would get in the way.
5. Bamboo Palm (Chamaedorea seifrizii)
Bamboo palms were included in the NASA study for formaldehyde, benzene, and trichloroethylene testing. They are larger than most plants on this list (up to 2 metres tall indoors) and add a different visual quality to a room.
They prefer indirect light of 150 to 500 foot-candles and need more consistent watering than succulents or snake plants. Keep the soil lightly moist but not waterlogged. Brown tips on the fronds usually indicate dry air rather than a watering issue. I find palms need more attention than the other plants here, but they reward it with lush, arching growth that fills a corner nicely.
6. Boston Fern (Nephrolepis exaltata)
Boston ferns tested well for formaldehyde removal, with research suggesting the root zone and soil microorganisms played a primary role in the process. As hanging plants indoor, they work well suspended from ceiling hooks or placed on high shelves where the fronds can cascade downward.
The trade-off is maintenance. Boston ferns are humidity-dependent and drop leaves when the air gets too dry, which in a centrally heated UK flat happens about five months of the year. I kept one for two winters and gave up after sweeping up brown leaflets every morning. If your bathroom has decent light (100+ foot-candles), that is the best spot. The steam from showers keeps humidity high.
7. Rubber Plant (Ficus elastica)
A recent study published in Water, Air, and Soil Pollution (2025) found rubber plants removed over 93% of benzene in 88 hours under controlled conditions. GC-MS analysis confirmed the plant was metabolically transforming the compound, not just trapping it on leaf surfaces.
Rubber plants grow into substantial specimens indoors (easily a metre or more in a large pot). They prefer bright indirect light (200-600 foot-candles) but tolerate lower levels. Water when the top 3-4cm of soil dries out. The large, glossy leaves collect dust quickly, so wipe them down every couple of weeks. Mine sits near a window and gets a leaf-clean every time I water it.
8. Chinese Evergreen (Aglaonema)
Chinese evergreens were tested for formaldehyde and benzene removal in the NASA study. They are also one of the most adaptable indoor plants low light conditions will support, handling as little as 50 foot-candles. The solid green varieties tolerate dimmer spots better than the pink or red cultivars, which need more light to maintain their patterning.
I grew one alongside my cast iron plant in my north-facing room for a year. New leaves appeared roughly every six weeks at around 60-80 foot-candles. They are quiet, undemanding plants that get on with growing without needing much from you. Water when the top third of the soil dries out and keep them away from cold draughts.
Air Purifying Indoor Plants That Are Also Easy to Grow
If you want plants from this list that need the least attention, start with pothos, snake plants, and Chinese evergreens. All three handle low light, tolerate irregular watering, and survive the dry air from central heating. They are easy indoor plants by any measure.
Spider plants and peace lilies are nearly as easy, with the added bonus that spider plants produce baby plantlets you can share, and peace lilies flower indoors. Both need a bit more water than the drought-tolerant trio above, but they will tell you when they are thirsty (spider plants curl their leaves; peace lilies droop).
The harder end of this list includes Boston ferns (humidity-dependent, messy shedding) and bamboo palms (need consistent moisture and more light). These are good plants, but they need more of your time.
Hanging Plants Indoor That Filter Air
Three plants on this list work well as hanging plants indoor: pothos, spider plants, and Boston ferns. All three produce trailing growth that looks good cascading from a high shelf or hanging planter.
Pothos is the lowest-maintenance option. It grows long trailing vines that you can drape along a shelf or train up a wall. Spider plants produce dangling stolons covered in baby plantlets, which creates a layered, full look. Boston ferns have the most dramatic cascading shape but need the most humidity.
If you are looking for a trailing plant for a spot that gets limited light, pothos handles 50-100 foot-candles without issue. Spider plants need at least 75. Boston ferns prefer 200+, ideally in a humid room. For a full directory of plants that handle shade, the A-Z low light plant guide covers more options.
What Actually Works for Indoor Air Quality
If your goal is genuinely cleaner air at home, here is what the evidence supports.
Open your windows. Even 10-15 minutes of ventilation replaces a significant volume of indoor air. Cross-ventilation (opening windows on opposite sides of the flat) is more effective than opening a single window. On high-pollution days in urban areas, ventilate in the early morning when outdoor air quality tends to be better.
Control pollution sources. Volatile organic compounds come from cleaning products, air fresheners, new furniture, paint, and building materials. Switching to low-VOC cleaning products and letting new furniture off-gas in a ventilated room before bringing it into your living space makes a bigger difference than any number of plants.
Use a HEPA air purifier. A standalone air purifier with a HEPA filter removes particulates and some VOCs at a rate that would require thousands of plants to match. They are not cheap, but they do the job that plants realistically cannot.
Plants do contribute to indoor comfort in other ways. They increase humidity slightly through transpiration, which helps in dry centrally heated rooms during winter. Multiple studies link indoor plants to reduced stress and improved mood. Those benefits are real and do not need to be inflated with debunked air-purification claims.
Grow plants because they look good, because tending them is satisfying, and because they make a room feel more alive. Just do not skip the air purifier and expect a peace lily to do the same job. It will not. For a broader look at getting started with houseplants, the indoor plants beginners’ guide covers the essentials.
Frequently Asked Questions
Do Indoor Plants Actually Clean the Air?
In sealed laboratory chambers, certain plants remove measurable amounts of volatile organic compounds like formaldehyde and benzene. In real homes with normal ventilation, the effect is negligible. A 2019 meta-analysis published in the Journal of Exposure Science and Environmental Epidemiology found you would need 100 to 1,000 plants per square metre of floor space to match the air-cleaning effect of simply opening a window.
Is the NASA Clean Air Study Accurate?
The NASA study (Wolverton, 1989) produced valid scientific results within its test conditions: sealed glass chambers with no air exchange and artificially elevated VOC levels. The problem is that those conditions do not exist in any real home or office. Buildings have continuous air exchange through ventilation, which dilutes VOCs far faster than plants can absorb them.
How Many Plants Would I Need to Actually Purify the Air in My Home?
According to research by Cummings and Waring at Drexel University, you would need between 100 and 1,000 plants per square metre of floor space to match what normal building ventilation already does. For a typical 60 square metre flat, that is somewhere between 6,000 and 60,000 plants. This is not practical.
What Actually Works for Improving Indoor Air Quality?
The American Lung Association recommends three approaches that are genuinely effective: source control (removing or reducing pollution sources like cleaning products and off-gassing furniture), ventilation (opening windows or using mechanical ventilation), and air filtration (standalone air purifiers with HEPA filters). Plants may slightly increase humidity, which helps with respiratory comfort, but they are not a substitute for these approaches.