Indoor
Houseplants Barely Purify Indoor Air
Reproducing the air-cleaning effect of one open window would take roughly 10-1,000 plants per square metre of floor.
The 1989 NASA Clean Air Study is real, and its results were real — inside small sealed chambers with no ventilation. A 2019 reanalysis in the Journal of Exposure Science and Environmental Epidemiology converted those chamber results into clean air delivery rates and compared them with normal building ventilation. Ordinary air exchange in a home outperforms potted plants by one to three orders of magnitude.
This is not an argument against houseplants. Humidity buffering, acoustic softening, and the well-documented effect on mood and attention are all genuine. Just do not buy a peace lily instead of fixing your ventilation.
Put this into practice
- Houseplant Light MatcherWhich houseplants suit this window?
More facts like this
- A North Window Gives the Most Consistent Light of Any AspectIn the northern hemisphere, a north-facing window delivers low but remarkably steady light with almost no risk of leaf scorch.
- Repotting Into a Much Bigger Pot Usually Kills the PlantGo up one pot size — about 2-5 cm in diameter. Jumping three sizes creates a swamp the roots cannot dry out.