Air purifying indoor plants do remove some pollutants in sealed laboratory tests, but in a real home the effect is small, and ventilation does far more. Plants like spider plant, snake plant, peace lily and Boston fern are still worth growing: they are easy, they look good, and they make a room nicer to live in. Just do not rely on them to clean your air.
I am Sawera Shahid, a botanist at Patch Plants. Most articles about air purifying indoor plants repeat the famous NASA study without its limits. Here is what the research really shows, which plants are the best picks, which are safe for pets and how to look after them.
What the Research Says About Air Purifying Indoor Plants
The idea comes from a 1989 NASA study that tested houseplants in sealed chambers. Plants did reduce certain volatile organic compounds (VOCs), such as formaldehyde and benzene, in those tests. Sealed chambers are very different from real rooms, though.
A later review by researchers at Drexel University looked at about a dozen studies across roughly 30 years. They concluded that ventilation dilutes VOCs much faster than plants can remove them. To match the air cleaning of even a couple of open windows, they estimated you would need 100 to 1,000 plants per square metre of floor space.
The Royal Horticultural Society has been testing this too. Its preliminary findings show that at typical low indoor light, plants take up carbon dioxide only at low rates, and the effect on a whole room is negligible. Which? summarises the evidence as plants helping “in certain circumstances, to some degree”, and suggests houseplants are best valued for wellbeing rather than as a substitute for ventilation or a good air purifier.
So the honest answer is that air purifying indoor plants are a pleasant extra, not a replacement for opening windows, controlling pollution sources or using a filter if you need one.
How Air Purifying Indoor Plants Work
Plants take in gases through tiny leaf pores called stomata, and soil microbes around the roots may also break down some compounds. Both processes depend on the plant being healthy and getting enough light. The RHS found that only a few species, including English ivy and peace lily cultivars, reached the light level needed to take up CO2 under typical indoor light. A plant squeezed into a dim corner will do very little.
- Leaf area: bigger, healthier plants have more surface to work with.
- Light: brighter spots mean more active growth.
- Healthy roots: good soil and sensible watering keep root-zone microbes active.
For help placing plants where they get enough light, see our complete indoor light guide.
Best Air Purifying Indoor Plants
These are the plants most often named in NASA-based lists of air purifying plants. I have chosen them because they are also easy to keep alive, which matters more than any claimed purifying score. Pet safety comes from the ASPCA plant lists.
| Plant | Light | Watering | Pets (ASPCA) |
|---|---|---|---|
| Spider plant | Bright indirect | When the top inch or so is dry | Non-toxic |
| Boston fern | Bright indirect, humid spot | Keep evenly moist | Non-toxic |
| Areca palm | Bright indirect | Keep lightly moist | Non-toxic |
| Snake plant | Low to bright indirect | Only when fully dry | Toxic |
| Peace lily | Low to medium indirect | When the top layer dries | Toxic |
| Pothos | Low to bright indirect | When the top layer dries | Toxic |
| Rubber plant | Bright indirect | When the top layer dries | Toxic |
| Dracaena | Low to bright indirect | When the top half dries | Toxic |
| Chinese evergreen | Low to medium indirect | When the top layer dries | Toxic |
| Philodendron | Medium to bright indirect | When the top layer dries | Toxic |
| Aloe vera | Bright light | Only when fully dry | Toxic |
Spider Plant (Chlorophytum comosum)
A spider plant is the easiest recommendation for beginners and pet owners. It grows quickly, tolerates a missed watering and produces plantlets you can pot up for free. See our spider plant care guide and, if the tips turn brown, why spider plant tips go brown.
Snake Plant (Sansevieria trifasciata)
Snake plant is one of the most forgiving houseplants you can own, tolerating low light and long gaps between waterings. You will often read that it releases oxygen at night and helps you sleep. It does use a night-time gas exchange method, but the amount is far too small to notice in a bedroom, so grow it because it is tough and attractive. The ASPCA lists it as toxic to dogs and cats. See our snake plant care guide.
Peace Lily (Spathiphyllum)
Peace lily copes with lower light than most flowering plants and tells you when it is thirsty by drooping. RHS researchers found peace lily cultivars among the few species that reach their light threshold in typical indoor light, which is a good sign for its performance indoors. It is toxic to pets according to the ASPCA. See the peace lily care guide and how often to water a peace lily.
Pothos (Epipremnum aureum)
Pothos is a trailing plant that adapts to low light and forgives neglect. It roots easily from cuttings, so a single plant becomes many. Pothos is toxic to dogs and cats. Our pothos care guide covers varieties and care.
Rubber Plant (Ficus elastica)
The large glossy leaves of a rubber plant make a strong statement and give plenty of leaf surface, but it wants bright light. Ficus plants are listed by the ASPCA as toxic to dogs. See the rubber plant care guide or our list of oversized indoor plants.
Boston Fern
Boston fern is a classic in these lists and is non-toxic to pets, but it needs more humidity and steady moisture than most plants here. It suits a bright bathroom or a hanging basket better than a dry, heated living room. See our Boston fern care guide.
Dracaena, Areca Palm, Chinese Evergreen, Philodendron and Aloe Vera
Dracaena is available in sizes from tabletop to floor-standing and is toxic to pets; our dracaena care guide has the detail. Areca palm needs bright indirect light and is non-toxic. Chinese evergreen is a good choice for dimmer rooms but is toxic to pets. Philodendron grows fast, trails or climbs, and is toxic too; see the philodendron care guide. Aloe vera needs a bright window and gritty soil; our aloe vera care guide covers it.
How Many Air Purifying Indoor Plants Do You Need?
You will often see a rule of thumb of one plant per 100 square feet. That figure is not backed by testing in real homes. The Drexel review suggests that matching normal ventilation would take hundreds of plants per square metre, which is not realistic in any home.
A practical approach is to decide how many plants you can keep healthy and well lit, rather than aiming for a number. Two or three thriving plants in a bright room are better than ten struggling ones in the dark.
Air Purifying Indoor Plants for Specific Rooms
Bedroom
Choose low-fuss plants such as spider plant or snake plant. Keep toxic ones away from pets that sleep in the room. See how to decorate your bedroom with plants.
Home Office
Pothos, snake plant and Chinese evergreen cope with lower light and irregular care. Our office plants for fluorescent lighting and home office plants guides go into more detail.
Bathroom
Boston fern, peace lily and spider plant enjoy the humidity if the room has some light. See the best plants for your bathroom and low light plants for a bathroom.
Pet-Safe Air Purifying Indoor Plants
If you have cats or dogs, the ASPCA lists spider plant, Boston fern and areca palm as non-toxic to both. It lists snake plant (saponins), pothos, peace lily, philodendron, dracaena, Chinese evergreen, aloe vera and ficus as toxic to dogs. Always check the plant against the ASPCA list before bringing it home, and see our guides to cat-friendly and dog-friendly plant choices.
Getting the Most From Air Purifying Indoor Plants
- Give them light. Light drives gas exchange, so a bright spot matters more than any particular species.
- Wipe the leaves. Dust blocks light, so clean large leaves with a damp cloth. See how to clean plant leaves.
- Water sensibly. Overwatering kills roots, and rotten roots do nothing. Our watering guide helps.
- Use good soil. See the soil mix guide.
- Rescue struggling plants. Try how to revive a dying plant.
Air Purifying Indoor Plants vs Air Purifiers
| Plants | Mechanical air purifier | |
|---|---|---|
| Air cleaning in real rooms | Small, hard to measure | Measurable, rated by clean air delivery rate |
| Allergens such as pollen and dust | Not filtered | Captured by HEPA filters |
| Running cost | Compost, water and light | Electricity and filter changes |
| Other benefits | Looks, mood, a little humidity | Consistent performance |
If air quality is a health concern, open windows, reduce pollution sources such as scented products, and consider a filter. Treat plants as a bonus.
Frequently Asked Questions
Do air purifying indoor plants really clean the air?
In sealed test chambers, yes, but in real homes the effect is very small. Research reviewed by Drexel University found that ventilation removes VOCs far faster than plants do, so plants are best treated as decoration with a little extra benefit.
What are the best air purifying indoor plants?
Spider plant, snake plant, peace lily, pothos, Boston fern and rubber plant are popular because they appear on NASA-based lists and are easy to grow. Choose by your light and pets rather than by purifying claims.
How many air purifying indoor plants do I need?
There is no tested number for real homes. Matching normal ventilation would take hundreds of plants per square metre, so aim for as many healthy, well-lit plants as you can look after.
Are there pet-safe air purifying indoor plants?
Yes. The ASPCA lists spider plant, Boston fern and areca palm as non-toxic to dogs and cats. Snake plant, pothos, peace lily and several others are toxic, so keep them out of reach.
Do air purifying indoor plants work in low light?
They survive, but they do less. Pothos, snake plant, peace lily and Chinese evergreen tolerate dim rooms, though the RHS found that low indoor light limits how much plants can take up.
Final Thoughts
Air purifying indoor plants are worth growing, just not for the reason most lists claim. As a botanist, my advice is to pick plants you will enjoy and can keep healthy, put them where there is decent light, and rely on fresh air for the actual air quality. For more ideas, browse our best indoor plants for beginners, low light house plants and the full indoor plants section.
Sources: RHS, Plants and indoor air quality; Drexel University, Potted plants do not improve air quality; Which?, Air purifying plants; ASPCA, Toxic and non-toxic plants.
