Do indoor plants clean the air?
Not in any way you would notice. You would need a room packed with plants to match even a modest purifier. Grow them for wellbeing, not for filtration.
The short answer
No, not meaningfully. Plants are good for mood and make a room pleasant, but they do not remove PM2.5 at any rate that matters in a home. No particular plant species changes that, whether areca palm, snake plant, money plant or peace lily.
Where the idea came from
A 1989 NASA experiment found that some plants reduced certain chemical vapours (VOCs) inside small, sealed test chambers over many hours. Those results were widely repeated as “plants purify the air”. But a sealed chamber with no air exchange is nothing like a home, and the study was about gases, not fine particles.
What later research found
A 2020 review of the evidence by researchers at Drexel University (Cummings & Waring) recalculated the chamber results for real buildings. They turned 196 lab results into a clean-air delivery rate per plant: the median was just 0.023 m³ per hour, for gases. Ordinary air leakage in a building already exchanges air far faster than that. To match it, you would need roughly 10 to 1,000 plants per square metre of floor. That’s not a room with plants, that’s a greenhouse.
For particles the picture is no better: leaves collect some dust, but the amount of air passing over them is tiny compared with a purifier’s fan.
Plants vs a purifier, roughly
A purifier delivering 300 m³/h of clean air passes the entire volume of a 140 ft² bedroom through its filter about eight times an hour. Even using the median plant figure for gases, matching that would take around 13,000 plants. For PM2.5, no study shows a measurable effect at realistic numbers.
So what should you do?
- Keep plants if you enjoy them. Greenery is good for wellbeing, and caring for plants is a pleasant indoor activity for older adults and children.
- Don’t count them in your protection budget. Spend that money on a properly sized HEPA purifier.
- Watch the soil. Overwatered pots can grow mould, which is not good for people with asthma or allergies.