Best Air-Purifying Plants
NASA really did test houseplants for air purification in 1989 — but a 2019 follow-up study found the real-world effect is far smaller than the popular version of that story suggests. Here's what actually held up.
The Plants NASA Actually Tested
In 1989, NASA researcher B.C. Wolverton sealed 12 common houseplants into test chambers and measured how much formaldehyde, benzene, and trichloroethylene they removed from the air over 24 hours. It's the source of almost every "top air-purifying plants" list you've seen — including this one. Three of the original 12 have full Olmi care guides:
Peace Lily
Spathiphyllum — One of the strongest performers for benzene and formaldehyde removal in the original chamber tests.
Care guide →Snake Plant
Dracaena trifasciata — Listed as "mother-in-law's tongue" in the original NASA report — tested for formaldehyde removal.
Care guide →Golden Pothos
Epipremnum aureum — Tested for formaldehyde removal; also one of the easiest plants on this list to keep alive.
Care guide →Also on NASA's Original List
These species were part of the same 1989 study but don't yet have a dedicated Olmi guide — solid choices if you want to round out a collection built around the original research rather than a generic best-of list.
Bamboo Palm
Chamaedorea seifrizii
English Ivy
Hedera helix
Chinese Evergreen
Aglaonema
Dracaena (several cultivars)
Dracaena spp.
The Part Most Lists Leave Out
NASA's study measured a sealed chamber, not a living room. Here's what changes when you scale it up to an actual home.
10 to 1,000 plants per square meter
What the 2019 review found: Cummings & Waring (Drexel University) reviewed 12 studies spanning 30 years and calculated a median single-plant clean air delivery rate of just 0.023 m³/h — a fraction of what normal building ventilation moves.
What it means for you: matching your home's existing air exchange with plants alone would take 10 to 1,000 plants per square meter of floor space, depending on the room. A few pots on a shelf won't move the needle on VOC levels — good ventilation and an actual air purifier will.
Track your plants in Olmi.
Air purification aside, a healthy plant is a nicer plant to have around. Set a watering reminder and keep every pot on a routine you'll actually stick to.
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Air-Purifying Plants FAQ
Do air-purifying plants actually work?
In a sealed lab chamber, yes — NASA's 1989 study found several common houseplants removed measurable amounts of formaldehyde, benzene, and other VOCs within 24 hours. In an actual room with normal air exchange, the effect is far smaller. A 2019 review by Drexel University researchers found you'd need 10 to 1,000 plants per square meter of floor space to match what a building's ordinary ventilation already does. Keep houseplants for the ones you love looking at — treat air purification as a minor bonus, not the main reason to buy them.
Which plants did NASA actually test?
Wolverton's 1989 NASA study tested 12 species in sealed chambers, including peace lily, golden pothos, mother-in-law's tongue (snake plant), bamboo palm, English ivy, and several dracaena varieties. Peace lily, pothos, and snake plant are the three from that original list that Olmi has full care guides for.
How many plants would I actually need to clean my air?
Per the 2019 Drexel University review, the median single houseplant has a clean air delivery rate of about 0.023 cubic meters of air per hour — a number so small that matching your home's natural ventilation would take somewhere between 10 and 1,000 plants for every square meter of floor space, depending on the room. A typical living room would need to look more like a greenhouse than a home to make a measurable dent.
Should I still get houseplants if they don't really purify the air?
That's a reason to enjoy them for what they demonstrably do well — several studies link having houseplants around to lower reported stress and better mood, and they're simply pleasant to look at and care for. If indoor air quality is a real concern in your home, a mechanical air purifier with a HEPA filter and better ventilation will do far more than any number of plants.
Which air-purifying plants are safe for cats and dogs?
Of the classic NASA-list plants, snake plant and pothos are both toxic to cats and dogs (mild calcium oxalate or saponin irritation, not an emergency), while peace lily is also toxic. If you want a pet-safe option, spider plant is non-toxic and is one of the plants most commonly discussed alongside NASA's research on VOC removal. See our full plant safety guide for a species-by-species breakdown.
Sources
The claims on this page are based on the original research and its most credible follow-up, not repeated marketing copy:
- NASA Technical Reports Server — Interior Landscape Plants for Indoor Air Pollution Abatement (B.C. Wolverton, 1989)
- Journal of Exposure Science & Environmental Epidemiology — Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies (Cummings & Waring, Drexel University, 2019)