In 1989, NASA conducted a landmark study to find the best plants for cleaning air in sealed environments like space stations. The results have since been applied to terrestrial living spaces, and the findings are genuinely compelling: certain houseplants are remarkably effective at removing volatile organic compounds (VOCs) — including benzene, formaldehyde, trichloroethylene, xylene, toluene, and ammonia — from indoor air.

The average American spends approximately 90% of their time indoors, where air pollutant levels can be 2-5x higher than outdoor levels. In modern, energy-efficient homes with good insulation, this effect is amplified. Adding air-purifying plants isn't a substitute for proper ventilation, but it's a meaningful, beautiful, and low-effort complement.

How Do Plants Purify Air?

Plants absorb air through tiny pores called stomata, primarily on their leaves. The roots and associated microorganisms in the soil also break down airborne chemicals. In NASA's study, plants were placed in sealed chambers with measured levels of specific chemicals. After 24 hours, many plants had removed 50-90% of the toxins present.

The Top Air-Purifying Plants

1. Snake Plant (Sansevieria / Dracaena trifasciata)

Removes: Benzene, formaldehyde, xylene, toluene, trichloroethylene

The Snake Plant tops nearly every air purification list, and for good reason. It's one of the most efficient air-cleaning plants in the NASA study, particularly effective at removing formaldehyde — commonly found in household cleaning products, paint, and furnishings. It also converts CO2 to oxygen at night (CAM photosynthesis), making it one of the few plants that actually improve bedroom air quality while you sleep.

Care: Nearly indestructible. Low light, infrequent watering. Perfect for beginners and neglectful plant parents.

2. Spider Plant (Chlorophytum comosum)

Removes: Benzene, formaldehyde, xylene, toluene, carbon monoxide

Spider Plants are exceptional at removing formaldehyde and benzene — two of the most common indoor pollutants. They're also champions at producing oxygen and have been shown to effectively remove carbon monoxide. They're fast-growing, produce babies you can propagate (hello, free plants!), and tolerate a wide range of conditions.

Care: Bright to medium indirect light. Water when soil is dry. Non-toxic to pets — a major advantage over many air-purifying plants.

3. Peace Lily (Spathiphyllum)

Removes: Benzene, formaldehyde, trichloroethylene, ammonia, xylene, toluene

The Peace Lily is the most effective plant in NASA's study for removing ammonia, which is commonly found in cleaning products, fertilizers, and some plastics. It also performed exceptionally well for removing all other tested toxins. Its elegant white spathes add beauty to any room, and it's one of the most expressive plants when thirsty — dramatically wilting and perking back up within hours of watering.

Care: Low to medium light. Keep soil moist. Toxic to cats and dogs.

4. English Ivy (Hedera helix)

Removes: Benzene, formaldehyde, trichloroethylene, xylene, toluene, ammonia

English Ivy performed exceptionally well across nearly all toxins tested in NASA's study. It's particularly effective at airborne fecal matter (yes, really) and mold spores — making it an excellent choice for bathrooms. As a trailing plant, it's versatile for hanging baskets or trained up supports.

Care: Medium to bright indirect light. Keep soil moderately moist. Mist regularly for humidity. Toxic to pets.

5. Aloe Vera (Aloe barbadensis)

Removes: Benzene, formaldehyde, trichloroethylene

While not as broadly effective as some others, Aloe Vera is particularly good at removing formaldehyde — one of the most common and concerning indoor pollutants. The practical bonus: you can break off a leaf and use the gel inside for burns, skin care, or even cooking.

Care: Bright direct or indirect light. Let soil dry completely between waterings. Excellent for sunny windowsills.

6. Golden Pothos (Epipremnum aureum)

Removes: Benzene, formaldehyde, xylene, toluene, carbon monoxide

Pothos is one of the most effective plants for removing formaldehyde and carbon monoxide. It's also one of the easiest plants you can grow, making it an excellent entry point for combining air purification with low-maintenance care.

Care: Low to bright indirect light. Water when soil is dry. Toxic to pets.

7. Dracaena (various species)

Removes: Benzene, formaldehyde, xylene, toluene, trichloroethylene

Dracaena species performed well across most tested toxins in the NASA study. Their architectural forms — ranging from compact bushes to tall tree-like specimens — make them excellent statement plants for living rooms, offices, and bedrooms.

Care: Low to medium indirect light. Let soil dry between waterings. Sensitive to fluoride — use filtered water if your tap water is heavily treated.

8. Boston Fern (Nephrolepis exaltata)

Removes: Formaldehyde, xylene, toluene, benzene

Ferns add much-needed humidity to indoor air through their natural transpiration — making them especially valuable in dry winter conditions. They're particularly effective at removing formaldehyde from the air.

Care: Bright indirect light (not direct sun). Keep soil consistently moist. Mist regularly or use a humidifier. Non-toxic to pets.

Important Caveats

A few things to keep in perspective:

  • Number matters: One plant in a large room won't significantly purify the air. NASA's study used 1 plant per 100 square feet of floor space — roughly 6-8 plants in a typical apartment living room.
  • Ventilation first: Plants complement good ventilation, not replace it. Open windows when possible, use exhaust fans when cooking or cleaning.
  • Real-world vs. lab: NASA's sealed chambers are different from real homes. But even at reduced effectiveness, the cumulative effect of multiple plants in a well-ventilated space is meaningful.
  • Pet safety: Several top air-purifying plants (Peace Lily, Pothos, English Ivy, Snake Plant in large amounts) are toxic to pets. Choose Spider Plant, Boston Fern, or Areca Palm if you have animals.

Growing air-purifying plants is one of those cases where doing something good for your health is also simply beautiful. Fill your home with these plants and breathe easier — literally and figuratively.

Want more plants for dark spaces? See our guide to low-light houseplants →