8 easy-care air-purifying plants: do they really purify the air?

Easy air-purifying houseplants like Spathiphyllum, Sansevieria or Chlorophytum do not actually purify the air in a home: according to the US Environmental Protection Agency (EPA), there is no evidence that a reasonable number of plants removes significant amounts of pollutants from homes and offices.

The myth stems from a 1989 NASA study conducted in small sealed chambers; calculations by Cummings and Waring, published online in 2019, show that 10 to 1,000 plants per m² would be needed to match ventilation.

This guide honestly explains what these studies say, what plants really offer (well-being, a little less dust, a little more humidity), and then introduces 8 easy-care plants and their toxicity to cats and dogs.

🌟 Air-purifying plant or air purifier: do plants really purify the air

No, not in a real home: air-purifying plants do remove certain pollutants in the lab, but far too slowly to make a difference compared with the air exchange in a home. The EPA sums it up this way: plants reduced certain chemical compounds in laboratory experiments, but there is currently no evidence that a reasonable number of plants removes significant amounts of pollutants from homes and offices.

In France, Santé.fr, the public health information service, says that the effectiveness of “air-purifying” plants has not been proven and that the tests conducted do not demonstrate effectiveness under real-world conditions.

The RHS (Royal Horticultural Society) agrees: reducing pollution sources and ventilating are generally more effective, and many plants, as well as supplemental lighting, would be needed to achieve an effect. Plants do, however, have genuine benefits, albeit more modest ones than the “air purifier” promise.

📊 8 easy-care air-purifying plants: a comparison

Here are 8 of the easiest indoor plants described as air-purifying, compared on what really matters in your home: light, ease of care, and toxicity to cats and dogs. The “NASA” column indicates whether the species appears in the 1989 report, tested in a sealed chamber: this is not proof of effectiveness in a home.

Growing information: NC State Extension and the RHS; toxicity: ASPCA wording for the species listed.

📋 Quick facts

The key points for indoor air and keeping these plants healthy, according to the EPA, Santé.fr, the RHS and NC State.

🪏 How to really improve the air in your home in 6 steps

To genuinely improve indoor air, the EPA recommends three strategies: eliminate or reduce pollution sources, ventilate with outdoor air, then filter if needed. Plants are not on the list, but they do have a place in a healthy home, as long as you don't expect them to do what they can't. Here are the steps, from most effective to most enjoyable.

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🧭 Air-purifying plants for the bedroom, office or living room: which should you choose

The right plant described as air-purifying depends on the room: its light, temperature and whether you have a cat matter much more than its supposed powers. This table matches each room with easy-care plants that thrive there, with an example from our selection. In every case, ventilation cleans the air; the plant brings the rest.

📐 Air purification by plants: what the 1989 NASA study actually measured

The study behind the myth is the NASA report “Interior Landscape Plants for Indoor Air Pollution Abatement”, published on September 15, 1989, by B. C. Wolverton, Anne Johnson, and Keith Bounds (document NASA-TM-101766).

The researchers placed potted plants in sealed Plexiglas chambers of around 0.4 to 0.9 m³ (0.76 m on each side for the smaller ones), injected benzene, trichloroethylene, or formaldehyde into them, then measured the drop in concentrations over 24 hours.

The plants tested included Spathiphyllum 'Mauna Loa', Sansevieria laurentii, Chlorophytum, several Dracaena including 'Janet Craig', ivy, chrysanthemum, gerbera, pothos, Aglaonema modestum, and the palm Chamaedorea seifrizii. The report concludes that the root zone and potting soil appear to be the most effective at removing volatile organic compounds, and primarily proposes an air filter combining plants and activated charcoal.

Two limitations change everything: a sealed chamber of less than 1 m³ is nothing like a ventilated room, and the authors themselves acknowledge that their high concentrations of 15 to 20 ppm were far above those commonly found in indoor air.

📐 The Cummings and Waring meta-analysis: 10 to 1,000 plants per m²

Bryan Cummings and Michael Waring, from Drexel University, published an analysis online in late 2019 in the Journal of Exposure Science and Environmental Epidemiology (volume 30, published in 2020), titled “Potted plants do not improve indoor air quality.”

They reviewed 12 chamber studies, comprising 196 experimental results, and converted them into clean air delivery rates (CADR), which make it possible to compare a plant with a building’s ventilation.

The median rate for one plant is 0.023 m³ per hour: to match a typical outdoor air exchange rate (around one air volume per hour), you would need to place 10 to 1,000 plants per m² of floor area, according to the paper’s abstract (Drexel University’s press release gives a figure of 100 to 1,000 plants per m²).

According to Drexel University, natural or mechanical ventilation dilutes volatile organic compounds much faster than plants can remove them. The authors are not saying that plants are useless; they recommend stopping research into their ability to passively purify air and instead exploring other biofiltration technologies or so-called biophilic benefits associated with contact with nature.

📐 Can a plant humidify the air? What we know about humidity and oxygen

Can a plant act as a humidifier? A little, but not much. Plants release water vapor through their leaves: Virginia Lohr of Washington State University reports a case where average relative humidity rose from 25% without plants to 30% with plants—a noticeable but moderate increase.

A University of Reading study published in 2024 in the Journal of Building Engineering measured a small but significant increase in humidity in a 28 m³ office furnished with plants, and concluded that air exchange has a greater effect on relative humidity than plants do.

As for oxygen and CO2, the University of Reading and the RHS showed that plants can remove CO2 from the air when well lit and watered; in the dark, they release it, but in negligible amounts: around 0.0876 g per hour for a Spathiphyllum 'Verdi', compared with 36 g per hour for a person.

No houseplant “produces the oxygen” in a bedroom: you can therefore keep one by your bed without worrying, but don’t expect miracles. If a plant is struggling with dry air, read our tips on how to increase air humidity.

🗓️ Caring for so-called air-purifying plants through the seasons

These 8 easy-care plants follow the rhythm of the light: they drink and grow more from spring through late summer, then slow down in winter. The RHS houseplant guide recommends checking the growing medium before watering rather than following a routine, and never fertilizing dry soil.

In winter, NC State recommends reducing watering for Chlorophytum and not leaving Spathiphyllum for long at temperatures below around 4 °C—a threshold that in practice only applies to a conservatory or an unheated room.

This is also the season when we close the windows: continue to air the room for a few minutes each day, and protect plants from radiators with our guide to caring for houseplants in winter.

📅 Seasonal care calendar

🐛 Mistakes to avoid with so-called air-purifying plants

The biggest mistake with a so-called air-purifying plant is relying on it to improve air quality and forgetting to air the room. The other mistakes are common care mistakes that end up damaging the plant and, sometimes, the air in the room. Here’s how to avoid them.

🌿 Our 8 easy-care air-purifying houseplants and their guides

These 8 plants won’t purify your air, but they are among the easiest and most enjoyable houseplants to live with.

Here are their guides, with one example from our selection; our set of 4 so-called air-purifying plants includes four of them, and our collection of so-called air-purifying plants brings together all the plants commonly described this way.

🔑 Why grow so-called air-purifying plants anyway?

Because their real benefits lie elsewhere than in filtration. The RHS reports that research suggests improved mood and reduced stress; it notes that improved attention has been found in some studies, but not all.

A study by the RHS and the University of Reading involving 520 participants and using photographs showed that soft, rounded shapes are considered most beneficial to well-being, and that an unhealthy plant is perceived as depressing. These effects relate to how people feel, not to their health: no plant cures anything.

So choose an easy-care plant suited to your light conditions, one you’ll enjoy watching grow: our guide to easy-care houseplants and our selection of large-leaf plants will help you find the right one.

🔑 So-called air-purifying plants and pets: what the ASPCA says

Several plants described as air-purifying are toxic to cats and dogs.

According to the ASPCA (American Society for the Prevention of Cruelty to Animals), Spathiphyllum is “Toxic to Dogs, Toxic to Cats”: its insoluble calcium oxalates cause mouth irritation and burning, excessive salivation, vomiting, and difficulty swallowing; pothos and Aglaonema modestum act in the same way.

Sansevieria (listed as “Snake Plant”) and Dracaena fragrans (listed as “Cornstalk Plant”) are toxic because of saponins.

By contrast, Chlorophytum comosum (the ASPCA’s Chlorophytum comosum entry) and Areca (the ASPCA’s “Areca Palm” entry) are classified as non-toxic, although NC State warns that the Areca’s terminal bud, or palm heart, should not be eaten.

We couldn’t find an ASPCA entry for Zamioculcas: NC State classifies it as moderately toxic to cats and dogs.

Discover our pet-friendly plants and our lists of non-toxic plants for cats and non-toxic plants for dogs.

✅ Our advice: air out your home first, then choose an easy-care plant

An air-purifying plant is no substitute for airing out your home or reducing sources of pollution: that’s the conclusion reached by the EPA, Santé.fr, and the meta-analysis by Cummings and Waring. Air out your home for 5 to 10 minutes a day, then choose an easy-care plant for enjoyment: Sansevieria or Zamioculcas for a dark room, Spathiphyllum for partial shade, Areca for a bright room, and Chlorophytum or Areca if you have a cat.

Find them in our easy-care plants, and remember that a healthy plant, properly watered and well lit, is the only one that will truly make you feel good.