🌿 Air quality
🔬 Science & well-being
🔬 In brief — what science really says
Established: plants absorb certain volatile organic pollutants and contribute to well-being · Nuanced: the effect on real air quality is more limited than claimed — dozens of plants per room would be needed · Real: slight humidity regulation, stress reduction, visual environment improvement · Best species: Spathiphyllum, Chlorophytum comosum 'Variegatum', Sansevieria, Boston Fern
"Purifying" plants are the subject of many claims — some based on serious studies, others heavily exaggerated by marketing. This guide honestly reviews what science really says and suggests the best species to improve your indoor environment.
What science really says
The 1989 NASA study — what it really says
In 1989, NASA published a study showing that certain plants absorbed volatile organic pollutants (formaldehyde, benzene, trichloroethylene) in highly controlled airtight chambers. This study was widely cited and amplified by marketing — to the point of creating an exaggerated myth.
What the study did not say: laboratory conditions (sealed chambers, artificially high concentrations) do not correspond to real living spaces. Later studies have shown that in open spaces, natural air exchanges greatly reduce this effect. For a measurable impact on air quality, 10 to 100 plants per square meter would be needed depending on conditions.
What is really established
The real benefits of indoor plants are different — and well documented in environmental psychology:
- Reduction of perceived stress and improvement of overall well-being
- Slight regulation of ambient humidity through transpiration
- Improvement of productivity and concentration in workspaces
- Oxygen production (low but real, and continuous at night for CAM species)
💡 The honest conclusion
Plants do not replace proper ventilation to purify the air. However, they truly contribute to well-being, ambiance, and quality of life in an indoor space. That’s already a lot. To go further, check out our detailed article on plants and air quality: myths and realities.
Indoor air pollutants
Indoor air contains several types of volatile organic pollutants (VOCs) whose sources are well identified. Some plants have shown the ability to absorb them in laboratory settings.
The best purifying plants
These species are among those identified by the NASA study and subsequent research as the most effective at absorbing organic pollutants. They have the advantage of being both decorative and relatively easy to care for.
Spathiphyllum tops the NASA list for its effectiveness on formaldehyde, benzene, and trichloroethylene. It blooms in low light and regulates ambient humidity through transpiration. One of the few plants that combines documented effectiveness and real decorative beauty.
See the Spathiphyllum →
The spider plant is one of the most effective in the NASA study for absorbing formaldehyde and carbon monoxide. Bonus: non-toxic for pets and children, very hardy and easy to care for. It also produces many plantlets that allow you to easily multiply the number of plants in the space.
See the Chlorophytum →
The Sansevieria combines two qualities: it is featured in the NASA study for its absorption of benzene, formaldehyde, and trichloroethylene, AND it produces oxygen at night thanks to its CAM metabolism. The easiest purifying plant to care for — monthly watering is enough.
See the Sansevieria →
The Boston fern is one of the champions of transpiration — it releases significant amounts of water vapor, which contributes significantly to regulating ambient humidity. Featured in the NASA study for formaldehyde and xylene, it is especially recommended for heated and dry spaces in winter.
See the Boston Fern →
Dracaena marginata is one of the most effective in the NASA study for benzene, trichloroethylene, and xylene — common pollutants in spaces where paints, varnishes, and solvents are used. Its slender shape is also very decorative in a contemporary interior.
See the Dracaena →
Aloe vera combines two advantages: cited in the NASA study for formaldehyde and benzene, it also produces oxygen at night thanks to its CAM metabolism. Very easy to care for, it grows well on a sunny windowsill. Its gel also has well-documented soothing properties.
See the Aloe vera →
The Pothos is cited in several studies for its effectiveness against formaldehyde and carbon monoxide. Very adaptable, it tolerates partial shade and missed watering. Its rapid growth makes it easy to multiply the number of plants in the space — a concrete advantage to increase the purifying effect.
See the Pothos →
The Ficus Elastica is effective against formaldehyde thanks to its large leaves that offer a significant absorption surface. The bigger the plant, the higher the total leaf surface — and therefore the more noticeable the effect. One large plant is worth several small ones from the purifying point of view.
See the Ficus Elastica →
The Zamioculcas has appeared in more recent studies for its absorption of xylene, toluene, and benzene. Its ability to thrive in very tough conditions (low light, missed watering) makes it the ideal purifying plant for the most demanding spaces.
See the Zamioculcas →
The Monstera is not included in the original NASA study, but its large leaf surface contributes to transpiration and humidity regulation. The amount of water vapor released by its large leaves is significant — and proper ambient humidity is one of the most important factors in indoor air quality.
See Monstera →Comparison — effectiveness by pollutant
| Plant | Formaldehyde | Benzene | Trichloroethylene | Regulates humidity |
|---|---|---|---|---|
| Spathiphyllum | ★★★ | ★★★ | ★★★ | High |
| Chlorophytum | ★★★ | ★★ | ★★ | High |
| Sansevieria | ★★ | ★★★ | ★★★ | Moderate |
| Nephrolepis | ★★★ | ★★ | ★★ | Very high |
| Dracaena marginata | ★★ | ★★★ | ★★★ | Moderate |
| Aloe vera | ★★★ | ★★★ | ★★ | Low |
| Pothos | ★★★ | ★★ | ★ | Moderate |
| Ficus Elastica | ★★★ | ★★ | ★ | Moderate |
| Zamioculcas | ★★ | ★★★ | ★★ | Moderate |
★★★ documented effectiveness · ★★ moderate effectiveness · ★ limited effectiveness. Based on NASA studies and subsequent laboratory research.
Maximize the benefits of plants in your interior
Multiply plants by propagation
Since more than one plant is needed for a noticeable effect, propagation is your best ally. The Pothos and the Chlorophytum are very easy to propagate — in a few months you can multiply one plant into several dozen. Complete guide: propagating your plants.
Favor large leaves
The total leaf surface area is the determining factor — a large plant with many big leaves is worth several small ones. The Monstera, the Ficus Elastica, and the Boston Fern offer a large surface area in contact with the air.
Do not neglect ventilation
Plants do not replace good ventilation. Air out your home for 10 to 15 minutes a day — it is the most effective way to refresh the air. Plants complement this action; they do not replace it.
Proper plant care
A stressed plant (overwatering, lack of light, pests) loses part of its purifying effectiveness. Check the monthly care calendar to keep your plants healthy all year round.
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Purifying plants for your interior
Spathiphyllum, Chlorophytum, Sansevieria, Boston Fern — a selection of the best-documented species to improve your indoor environment.
Frequently asked questions
Yes, but to a more limited extent than announced. The 1989 NASA study demonstrated the absorption of organic pollutants under laboratory conditions. In real spaces, dozens of plants per room would be needed for a measurable effect. However, plants do genuinely contribute to well-being, humidity, and quality of life. To understand everything: plants and air quality: myths and realities.
The Spathiphyllum 'Bingo Cupido' and Chlorophytum comosum 'Variegatum' are most cited for their versatility on several pollutants (formaldehyde, benzene, trichloroethylene). Sansevieria and Dracaena marginata are particularly effective on benzene and trichloroethylene.
Recent studies suggest between 10 and 100 plants per m² for a measurable effect — well beyond practical. The most realistic approach: multiply your plants by propagation (the Pothos and Chlorophytum comosum 'Variegatum' are very easy to propagate), and choose species with large leaf surface area. See the propagation guide.
Large-leaf, fast-growing plants absorb the most CO2: Monstera, Ficus Elastica, Strelitzia. Sansevieria and Aloe vera have a CAM metabolism that allows them to continue absorbing CO2 at night — a unique feature.
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Improve Your Indoor Environment
Each plant comes with its care sheet — to maintain the effectiveness of your purifying plants all year round.
