PLANTS IN SPACE
Research on plants that purify the air in space stations can help us live healthier lives right here on terra firma. Yvonne Pecujac reports.
“Houseplants can play a big part in combatting indoor air pollution, even in sealed environments such as space stations where air quality is a life or death issue.
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“The World Health Organisation still ranks indoor air pollution as one of the biggest factors impacting human health.”
“As researchers put it: for humans, plants are a life support system. ”
“Researchers found that common indoor plants ... were top performers in reducing toxins.”
IN THE 70s, 80s and 90s the US space agency NASA – in a race with private space researchers and a USSR team working in Siberia – was studying how to deal with air pollution in sealed space habitats such as the space station or, as they envisaged then, moon bases. Their attention turned to the role that the humble indoor houseplant could play in purifying indoor air pollution.
Since Earth’s atmosphere originates from living green plants, the concept of using houseplants to purify and revitalise the indoor atmosphere of tightly sealed structures seemed only logical. As researchers put it: for humans, plants are a life support system.
As part of their investigation, NASA scientists looked at problematic closed environments such as planes and offices in tightly sealed energy-efficient buildings filled with synthetic material that off-gassed – a perfect storm called “Sick Building Syndrome”.
Over a number of studies they found that plants filtered and improved indoor air quality, and that all parts of the plant – leaves, roots, soil and microorganisms working at the root zone – were involved. They even found plants and soil continuously exposed to toxins improved their performance as the soil microorganisms adapted and became more efficient at utilising toxins such as Benzene and Formaldehyde as a food source.
Researchers found that indoor houseplants suppressed the growth of airborne microbes such as mould spores in their immediate area and speculated that this was why low-light houseplants that had evolved in the humid environment beneath the canopy of tropical rainforests could protect themselves from being overwhelmed by moulds and other microbes that flourish in damp, warm, low-light environments.
In 1989 when NASA’s groundbreaking Clean Air Report was published, the World Health Organisation estimated that 30% of all new buildings had varying degrees of indoor air pollution. More than 30 years later, the World Health Organisation still ranks indoor air pollution as one of the biggest factors impacting human health, not surprising when you consider that many people spend most of their lives indoors.
The researchers found that common indoor plants such as the Peace Lily (Spathiphyllum sp.), Bamboo Palm (Chamaedorea seifrizii), Boston Fern (Nephrolepis exaltata) and even the humble Gerbera (Gerbera jamesonii) were top performers in reducing common off-gassing toxins such as Benzene, Trichloroethylene and Formaldehyde along with Ammonia and Xylene. Scientists concluded that houseplants can play a big part in combatting indoor air pollution, even in sealed environments such as space stations where air quality is a life or death issue.
One of the great things about the many types of plants that were tested is the wide variety that did well across the board: from ferns, palms and Peace Lily to Mother-in-law’s Tongue and Dracaena: there’s a lot of plant styles to choose from. It is worth noting that plants differed in their effectiveness at purifying different toxins – and some of the plants are toxic to animals – so it may be worth looking up information on their performance along with scientist Bill Wolverton’s pick of top rating plants (see Resources).
One of the plants we like that consistently rated highly is the humble Peace Lily, a low-light indoor plant with lush foliage that thrives on neglect and performs like a champion. Put a couple of plants around your home and office, and spare a thought for how hard they’re working to clean your air as you open a window or door to let a refreshing breeze flow through your space.
Oh, and Sick Building Syndrome? Studies on this showed that symptoms are minimal in naturally ventilated buildings with high levels of microorganisms while symptoms are highest in mechanically ventilated buildings with low levels of microorganisms.
Bill Wolverton
This US environmental engineer with a background in marine biology and chemistry worked as a scientist for the US Air Force and Navy before spending nearly 20 years for NASA researching how plants can combat toxins and pathogens in sealed space environments. His groundbreaking research has continued to have implications for the environment in which we live and work, and has influenced green building and architecture, and biophilic design. He has written two books, How to Grow Fresh Air (1996) and Plants: Why You Can’t Live Without Them (2010), and still works as an environmental consultant in the area of phytoremediation: using plants to clean our air, water and environment (www.wolvertonenvironmental.com).
RESOURCEs
Chauhan, P.; Rawat, S.; Gauba, P. (2017), Role of plants in indoor air remediation. International Journal of Engineering Technology Science and Research, 4(9), pp749-756.
https://www.researchgate.net/publication/319979551_Role_of_Plants_in_Indoor_Air_Remediation
Kays S, Phytoremediation of indoor air: Current state of the art (2011), pp3-21, In: The Value Creation of Plants for Future Urban Agriculture, K.J. Kim (ed.), Nat. Inst. Hort. Herbal Science, RDA, Suwon, Korea.
https://www.researchgate.net/publication/303445805_Phytoremediation_of_indoor_air_-_Current_state_of_the_art
NASA Clean Air Report
Wolverton, B.C.; Douglas, W.L. and Bounds, K. (1989), Interior landscape plants for indoor air pollution abatement (Report). NASA. NASA-TM-101766.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930073077.pdf
Wolverton, 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), pp11-15.
http://wolvertonenvironmental.com/MsAcad-93.pdf
Wolverton, B.C. (1996) How to Grow Fresh Air. New York: Penguin.
Wolverton, B.C. and Takenaka K. (2010) Plants: Why You Can’t Live Without Them, New York: Roli.
The NASA guide to air-filtering houseplants based on performance
https://imgur.com/gallery/pZKrtyE
Feb 19, 2016
Beautiful Houseplants That Clean Indoor Air (Bill Wolverton’s online article ranking the performance of indoor plants)
https://bottomlineinc.com/life/home-improvements/beautiful-houseplants-that-clean-indoor-air
Aug 29, 2018
Can indoor plants really purify the air?
http://time.com/5105027/indoor-plants-air-quality/
Jan 17, 2018, Time Magazine