The NASA Clean Air Study was a project led by the National Aeronautics and Space Administration (NASA) in association with the Associated Landscape Contractors of America (ALCA) 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 (benzene, formaldehyde, and trichloroethylene were tested).
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:Wolverton, B. C., et al. A study of interior landscape plants for indoor air pollution abatement: an interim report. NASA. September, 1989. Variegated snake plant / mother-in-law's tongue (Sansevieria trifasciata laurentii) English ivy (Hedera helix) Peace lily (Spathiphyllum 'Mauna Loa') Chinese evergreen (Aglaonema modestum) Bamboo palm (Chamaedorea seifrizii) Red-edged dracaena, marginata (Dracaena marginata) Cornstalk dracaena, mass cane/corn cane (Dracaena fragrans 'Massangeana') Weeping fig (Ficus benjamina)American Society for Horticultural Science. Indoor plants can reduce formaldehyde levels. ScienceDaily. February 20, 2009. Quote: "...Complete plants removed approximately 80% of the formaldehyde within 4 hours. Control chambers pumped with the same amount of formaldehyde, but not containing any plant parts, decreased by 7.3% during the day and 6.9% overnight within 5 hours..." In reference to: Kim, J. K., et al. (2008). Efficiency of volatile formaldehyde removal by indoor plants: contribution of aerial plant parts versus the root zone. Horticultural Science 133: 479-627. Barberton daisy, gerbera daisy (Gerbera jamesonii) Florist's chrysanthemum, pot mum (Chrysanthemum morifolium) 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 paperWolverton, B. C. and J. D. Wolverton. (1993). Plants and soil microorganisms: removal of formaldehyde, xylene, and ammonia from the indoor environment. Journal of the Mississippi Academy of Sciences 38(2), 11-15. and 1996 bookWolverton, B. C. (1996) How to Grow Fresh Air. New York: Penguin Books. 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 removedPottorff, Laura. Plants "Clean" Air Inside Our Homes. Colorado State University & Denver County Extension Master Gardener. 2010. Total μg/h of formaldehyde removed Total μg/h of trichloroethylene removedxylene and tolueneammoniaDwarf date palm (Phoenix roebelenii)01,3850Areca palm (Dypsis lutescens)010Boston fern (Nephrolepis exaltata 'Bostoniensis')01,8630Kimberley queen fern (Nephrolepis obliterata)01,3280English ivy (Hedera helix)579402 -1,120298 Spider plant (Chlorophytum comosum)05600Devil's ivy, Pothos plant (Epipremnum aureum)010Peace lily (Spathiphyllum 'Mauna Loa')1,7256741,128Flamingo lily (Anthurium andraeanum)000Chinese evergreen (Aglaonema modestum)604Wolverton, B. C., et al. Interior landscape plants for indoor air pollution abatement: final report. NASA. September, 1989. pp 11-12.1830Bamboo palm (Chamaedorea seifrizii)1,4203,196688Parlour Palm (Chamaedorea elegans)06600 Lady Palm (Rhapis excelsa)08760 Variegated snake plant, mother-in-law's tongue (Sansevieria trifasciata 'Laurentii')1,1961,304405Heartleaf philodendron (Philodendron cordatum)03530Selloum philodendron(Philodendron bipinnatifidum)03610Elephant ear philodendron (Philodendron domesticum)04160Red-edged dracaena (Dracaena marginata)1,2648531,137Cornstalk dracaena (Dracaena fragrans 'Massangeana')0938421Weeping fig (Ficus benjamina)09400Barberton daisy (Gerbera jamesonii)4,48611,622Florist's chrysanthemum (Chrysanthemum morifolium)3,2051,4500Rubber plant (Ficus elastica)010Dendrobium orchids (Dendrobium spp.)07560Dumb canes (Dieffenbachia spp.)07540King of hearts (Homalomena wallisii)06680Moth orchids (Phalaenopsis spp.)02400Aloe vera (Aloe vera)100Janet Craig (Dracaena fragrans 'Janet Craig'/Cornstalk Plant)1,0821,361 - 2,037764Warneckei (Dracaena deremensis 'Warneckei')1,630760573Banana (Musa acuminata)04880
See also Dracaena reflexa Green wall Indoor air quality Phytoremediation Rain garden Sick building syndrome
References
External links 'Interior Landscape Plants for Indoor Air Pollution' How to Grow Your Own Fresh Air – TED 2009. An extension of the TED Talk.