NASA Clean Air Study
The NASA Clean Air Study was a project led by the National Aeronautics and Space Administration in association with the Associated Landscape Contractors of America in 1989, to research ways to clean the air in sealed environments such as space stations. Its results suggested that, in addition to absorbing carbon dioxide and releasing oxygen through photosynthesis, certain common indoor plants may also provide a natural way of removing volatile organic pollutants.
These results are not applicable to typical buildings, where outdoor-to-indoor air exchange already removes volatile organic compounds (VOCs) at a rate that could only be matched by the placement of 10–1000 plants/m of a building's floor space.
The results also failed to replicate in future studies, with a 2014 review stating that:
List of plants studied
The following plants were tested during the initial 1989 study:- Variegated snake plant / mother-in-law's tongue
- English ivy
- Peace lily
- Chinese evergreen
- Bamboo palm
- Red-edged dracaena, marginata
- Cornstalk dracaena, mass cane/corn cane
- Weeping fig
- Barberton daisy, gerbera daisy
- Florist's chrysanthemum, pot mum Dracaena deremensis 'Janet Craig'Dracaena deremensis 'Warneckei'
Additional research
Since the release of the initial 1989 study, titled A study of interior landscape plants for indoor air pollution abatement: An Interim Report, further research has been done including a 1993 paper and 1996 book by B. C. Wolverton, the primary researcher on the original NASA study, that listed additional plants and focused on the removal of specific chemicals. A different study in 2004 has also shown that the micro-organisms in the soil of a potted plant remove benzene from the air, and that some plant species themselves also contribute to removing benzene.Other studies
Plants studied in various similar studies on air filtration:| Plant, removes: | Total μg/h of benzene removed | Total μg/h of formaldehyde removed | Total μg/h of trichloroethylene removed | xylene and toluene | ammonia |
| Dwarf date palm | 0 | 1,385 | 0 | ||
| Areca palm | 0 | 1 | 0 | ||
| Boston fern | 0 | 1,863 | 0 | ||
| Kimberley queen fern | 0 | 1,328 | 0 | ||
| English ivy | 579 | 402 -1,120 | 298 | ||
| Spider plant | 0 | 560 | 0 | ||
| Devil's ivy, Pothos plant | 0 | 1 | 0 | ||
| Peace lily | 1,725 | 674 | 1,128 | ||
| Flamingo lily | 0 | 0 | 0 | ||
| Chinese evergreen | 604 | 183 | 0 | ||
| Bamboo palm | 1,420 | 3,196 | 688 | ||
| Parlour Palm | 0 | 660 | 0 | ||
| Lady Palm | 0 | 876 | 0 | ||
| Variegated snake plant, mother-in-law's tongue | 1,196 | 1,304 | 405 | ||
| Heartleaf philodendron | 0 | 353 | 0 | ||
| Selloum philodendron | 0 | 361 | 0 | ||
| Elephant ear philodendron | 0 | 416 | 0 | ||
| Red-edged dracaena | 1,264 | 853 | 1,137 | ||
| Cornstalk dracaena | 0 | 938 | 421 | ||
| Weeping fig | 0 | 940 | 0 | ||
| Barberton daisy | 4,486 | 1 | 1,622 | ||
| Florist's chrysanthemum | 3,205 | 1,450 | 0 | ||
| Rubber plant | 0 | 1 | 0 | ||
| Dendrobium orchids | 0 | 756 | 0 | ||
| Dumb canes | 0 | 754 | 0 | ||
| King of hearts | 0 | 668 | 0 | ||
| Moth orchids | 0 | 240 | 0 | ||
| Aloe vera | 1 | 0 | 0 | ||
| Janet Craig | 1,082 | 1,361 - 2,037 | 764 | ||
| Warneckei | 1,630 | 760 | 573 | ||
| Banana | 0 | 488 | 0 |