Not in any way you would notice. Indoor plants do absorb small amounts of some gases, but in a normal home the effect is tiny compared with opening a window, and plants do nothing meaningful for PM2.5, the fine particles behind India’s winter smog. Keep plants for how they make a room feel; use ventilation and a HEPA filter for the air.
The Short Answer
Lists of “air purifying plants” are among the most shared home tips in India, usually with the snake plant, money plant, areca palm and peace lily at the top. The claim is not completely invented: plants and the microbes in their soil can take up some volatile chemicals. The problem is scale. A few pots in a living room process a very small volume of air compared with the air that leaks in and out of the room every hour, let alone the air a purifier moves.
Bottom line: plants are good for wellbeing, not for air cleaning. For smog season, the useful tools are ventilation when outdoor air is cleaner, and HEPA filtration when it is not.
Where the Idea Came From: the NASA Study
Almost every “plants clean the air” article traces back to a 1989 NASA study, often called the Clean Air Study. It looked at how houseplants might help clean air in sealed spaces, with a future space station in mind.
The key detail is how it was done. Plants were placed in small, sealed test chambers, a known amount of a chemical was injected, and researchers measured how the level fell over time. In a small sealed box with no fresh air coming in, even a slow removal process shows up clearly.
A home is the opposite of a sealed chamber. Air constantly leaks in and out through doors, windows, gaps and exhausts, and new pollution keeps arriving. The chamber result was real, but it does not transfer to a living room.
What Later Research Found
Researchers have since gone back over the chamber studies and asked the obvious question: how many plants would a real home need to match what ordinary ventilation already does?
A widely cited review by Cummings and Waring, published in 2019, converted the chamber results into a form that can be compared with real buildings. Their conclusion was that you would need an impractically large number of plants per square metre of floor, far more than anyone could fit in a home, to equal the air cleaning that normal air exchange through a building already provides.
In other words, the gas removal plants offer is swamped by the air that moves through a room anyway. Adding a few more pots does not change that.
Why Plants Do Nothing for PM2.5
Even the NASA study was about gases (volatile organic compounds), not particles. That matters in India, because the pollution that sends the AQI into Poor, Very Poor and Severe from October to January is mostly PM2.5: fine particles from vehicles, stubble burning, waste burning and firecrackers.
- To remove particles, air has to be pushed through a filter. A plant has no fan and no filter. A few particles land on leaves, but the room’s air is not being drawn past them in any meaningful volume.
- Dusty leaves do not mean the plant is “cleaning” the air; settled dust would have settled on the floor or shelf anyway.
- No plant reduces carbon monoxide or adds a meaningful amount of oxygen to a room. Neither does an air purifier, for that matter: see what air purifiers cannot remove.
There is also a downside worth knowing. Overwatered pots and constantly damp soil can grow mould, and mould releases spores into the air. For anyone with allergies or asthma, a crowd of wet pots in a bedroom can make the air worse, not better. Let the top of the soil dry between waterings, use pots with drainage, and keep heavily watered plants out of the bedroom of anyone sensitive.
A filter only works if it moves enough air for your room. Find the CADR your room needs before you buy any purifier.
Size Your Room →Plants vs Ventilation vs a HEPA Purifier
| Indoor plants | Opening windows | HEPA air purifier | |
|---|---|---|---|
| PM2.5 and PM10 | No meaningful effect | Lowers indoor PM only when outdoor air is cleaner; raises it on smog days | Captures both; how fast depends on CADR vs room size |
| Gases and odours (VOCs) | Very small effect in a real home | Effective, by diluting with outdoor air | Some, if it has activated carbon; not every gas |
| Carbon dioxide from breathing | No meaningful effect | Effective | No effect |
| Works in Severe AQI? | No | No, it brings the smog in | Yes, in a closed room sized correctly |
| Downsides | Mould risk from wet soil | Lets in dust, noise and smog | Running cost and filter replacement |
To the question “do plants clean air better than a budget HEPA purifier?”, the answer is no. Even a modest HEPA purifier sized for the room removes far more particles than any number of plants you could fit in it. Our guide on whether air purifiers actually work covers what a purifier can and cannot be expected to do.
The best combination for most Indian homes: air the house briefly when the AQI for your city is at its lowest point in the day, run a HEPA purifier in the rooms you use when it is high, and control indoor sources such as frying without an exhaust and burning incense in closed rooms.
Keep Your Plants, for the Right Reasons
None of this means you should give your plants away. Greenery at home is widely associated with feeling calmer and more pleasant surroundings, and looking after plants is a good habit. Just do not count them as air-cleaning equipment, especially not for a child, an older parent, or anyone with asthma during smog season.
A few habits keep plants and clean air working together:
- Pick hardy, low-water plants that suit your light, so the soil is not wet all the time.
- Wipe dusty leaves with a damp cloth rather than dusting them dry, which only puts the dust back into the air.
- Keep pots on the balcony or in the living room rather than crowding a bedroom, and check the soil surface and saucers for mould or a musty smell.
- Do not let a plant shelf block the intake or outlet of your air purifier; it needs clear space around it to move air.
If the reason you were buying plants was a family member’s cough or wheezing in winter, the plants will not fix it. Get the room’s PM2.5 measured, filter the air properly, and see a doctor if symptoms continue.
Frequently Asked Questions
Do indoor plants really purify the air?
Only very slightly. Plants and their soil microbes can take up small amounts of some gases, but in a normal home that effect is tiny compared with ordinary air exchange through doors and windows. Plants do nothing meaningful for PM2.5, the fine particles behind winter smog in Indian cities. Keep them for wellbeing, not as air cleaners.
What did the NASA plant study actually prove?
The 1989 NASA study found that plants could reduce some volatile chemicals inside small, sealed test chambers. A home is not sealed: air keeps leaking in and out and new pollution keeps arriving. Later analysis, including Cummings and Waring in 2019, concluded you would need an impractically large number of plants per square metre to match normal ventilation.
Do snake plants or money plants remove PM2.5?
No. Removing particles needs air to be pushed through a filter, and plants have neither a fan nor a filter. Some dust settles on leaves, but it would have settled somewhere else anyway. For PM2.5 during smog season, a HEPA air purifier sized for the room is the tool that works.
Are indoor plants better than a budget HEPA air purifier?
No. A HEPA purifier with a CADR suited to the room removes far more particles than any number of plants you could fit in it, and plants do almost nothing for PM2.5. Plants also cannot react when pollution spikes. The budget purifier needs to be sized correctly and have its filter replaced on time to do its job.
Can indoor plants make air quality worse?
They can. Overwatered pots and soil that stays damp can grow mould, which releases spores into the air. That can bother people with allergies or asthma. Use pots with drainage, let the top of the soil dry between waterings, and keep heavily watered plants out of the bedroom of anyone who is sensitive.
Which plants are best for indoor air quality in India?
No plant meaningfully improves indoor air quality in a real home, so choose plants for how easy they are to care for in your light and climate, not for air-cleaning claims. Hardy, low-water plants reduce the mould risk from damp soil. For cleaner air, rely on ventilation when outdoor AQI is low and a HEPA purifier when it is high.
For particles that plants cannot touch, Boon Airvana pushes air through an H13 HEPA filter and shows you the PM2.5 level in the room as it falls.
See Boon Airvana →