Are plants air cleaners ?
Benzene, formaldehyde, trichloroethylene, ammonium chloride, pentachlorophenol (pcp), carbon monoxide, radiation from our appliances like computer monitors and television sets... air within our homes , classrooms, kindergartens, offices and factories is significantly more polluted than the air outside. All habitats with low ventilation and with an aim to reduce energy costs caused by air purifier devices are concerned. Awareness of this public health issue has much improved over the recent years. The U.S. Environmental Protection Agency ranks now indoor air pollution—which originates from many conventional building materials and chemicals commonly used indoor —as one of the top five threats to public health. An average American home has 100 to 200 different air contaminants.
International agencies such as WHO or Greenpeace have issued precise guidelines and warnings based on scientific findings that are worth reading and thinking over. [see our post : WHO and Greenpeace warnings ] The findings are alarming, especially considering that most of us spend our time dwelling in our homes and in office buildings.
" Since man's existence on Earth depends upon a life support system involving an intricate relationship with plants and their associated microorganisms, it should be obvious that when he attempts to isolate himself in tightly sealed buildings away from this ecological system, problems will arise. " says Wolverton a former NASA scientist in " Interior Landscape Plants for Indoor Pollution Abatement".
In the eighties the NASA researched techniques for cleansing the atmosphere in space stations to keep their habitat fit for travels over extended periods of time. Unexpected experiment results over two years in investigations supported by the NASA and the Associated Landscape contractors of America (ALCA) [see below : Scientific sources ] confirmed that certain tropical plants with low light requirements were able to use stunning mechanisms to remove harmful gases out of the air, thanks to their particular ability to photosynthesize in harder conditions. This removal is more efficient with time. We show below test results after only 24 hours of exposure. The results are just amazing. Certain plants clean air in habitats : this can be up to 90 % of the volatile pollutants.
Since then an increasing number of laboratories the world over have sustained that a wide range of volatile contaminants toxic to human health could be efficiently trapped and degraded with certain plants that have evolved in tropical forests. We show below a chart of the plants with the corresponding rates of degradation.
Further below on this page is an extended A to Z list of the plants that have been tested by various programmes following the first experiments cited above. Not only are these tropical and sub tropical plants able to tolerate low light, they are generally easy growers with low maintenance requirements. They are ideal for promoting green choices in our indoor setting. Some are supplied by aleyagarden.com
It would be demonstrated that one plant for every 10 square metres suffices to remove out of a room 70 - 90 % of the pollutants, provided that several species are mixed. The time of removal varies from a few hours to only a few days. [see below : Air Cleaning Plants in Scientific Literature]
SOURCES of the AIRBORNE POLLUTANTS :
Sources of airborne Benzene : Petroleum Products Synthetic Fibers Plastics Inks & DyesRubber Products Detergents Tobacco Smoke
Sources of airborne Formaldehyde : Foam Insulation Plywood or Particle Board
Carpeting Furniture Paper Products Cleaners
Sources of airborne Trichloroethylene : Dry Cleaning Inks & Dyes Adhesives Varnishes Lacquers Paints
Plant species that are most efficient at air decontamination - they are listed below - originate from tropical and sub-tropical forests, where they evolved receiving light filtered through the canopy : in order to survive they used a leaf composition allowing them to photosynthesize efficiently despite the reduced light. In this connection they could find ways to process gasses in the air efficiently.
PLANTS that DECONTAMINATE VOLATILE POLLUTANTS THROUGH THE PROCESSES OF PHOTOSYNTHESIS
Removal from a Sealed Experimental Chamber by Houseplants During a 24-h Exposure Period
Plants breaking down Benzene & % of Benzene d ecomposition : Hedera helix 90% Spatiphyllum 80% Dracaena marginata 79% Dracaena deremensis 78% Dracaena deremensis
'Warneckii' 70% Sansevieria spp 48%
Plants breaking down Formaldehyde & % of Formaldehyde decomposition : Aloe barbadensis 90% Chlorophytum comosum 86% Philodendron 86-76% Dracaena fragrans 70%
Dracaena Massangeana 70% Ficus benjamina 70% Epipremnum aureum 67% Syngonium
podophyllum 67% Dracaena marginata 60% Dracaena deremensis Warneckii
50% Spathiphyllum 50%
Plants breaking down Trichloroethylene & % of Trichloroethylene decomposition : Spathiphyllum 50% Dracaena deremensis Warneckii 24% Dracaena deremensis 20% Dracaena marginata 13% Hedera helix 11%
Plants breaking down carbon monoxide & % of carbon monoxide decomposition : Chlorophytum comosum 96% Epipremnum aureus 75%
Schlumbergera bridgesii Schlumbergera rhipsalidopsis
WHO air quality guidelines
Updated 08 January 2008
Table of contents
Preface (11kb PDF)
Part I. General
1. Introduction (35kb PDF)
2. Criteria used in establishing guideline values (70kb PDF)
3. Summary of the guidelines (39kb PDF)
4. Use of the guidelines in protecting public health (52kb PDF)
Part II. Evaluation of Human Health Risks
5. Organic pollutants
5.1 Acrylonitrile (178kb PDF) *
5.2 Benzene (83kb PDF)
5.3 Butadiene (72kb PDF)
5.4 Carbon disulfide (194kb PDF) *
5.5 Carbon monoxide (204kb PDF)
5.6 1,2-Dichloroethane (176kb PDF) *
5.7 Dichloromethane (184kb PDF)
5.8 Formaldehyde (284kb PDF)
5.9 Polycyclic aromatic hydrocarbons (PAHs) (104kb PDF)
5.10 Polychlorinated biphenyls (PCBs) (262kb PDF)
5.11 Polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) (331kb PDF)
5.12 Styrene (314kb PDF)
5.13 Tetrachloroethylene (222kb PDF)
5.14 Toluene (91kb PDF)
5.15 Trichloroethylene (219kb PDF)
5.16 Vinyl chloride (181kb PDF) *
6. Inorganic pollutants
6.1 Arsenic (64kb PDF)
6.2 Asbestos (194kb PDF) *
6.3 Cadmium (200kb PDF)
6.4 Chromium (67kb PDF)
6.5 Fluoride (48kb PDF)
6.6 Hydrogen sulfide (148kb PDF) *
6.7 Lead (225kb PDF)
6.8 Manganese(183kb PDF)
6.9 Mercury (219kb PDF)
6.10 Nickel (64kb PDF)
6.11 Platinum (193kb PDF)
6.12 Vanadium (170kb PDF) *
7. Classical pollutants
7.1 Nitrogen dioxide (136kb PDF)
7.2 Ozone and other photochemical oxidants (289kb PDF)
7.3 Particulate matter (353kb PDF)
7.4 Sulfur dioxide (168kb PDF)
8. Indoor air pollutants
8.1 Environmental tobacco smoke (ETS) (99kb PDF)
8.2 Man-made vitreous fibres (MMVF) (229kb PDF)
8.3 Radon (224kb PDF)
Part III. Evaluation of Ecotoxic Effects
9. General approach (28kb PDF)
10. Effects of sulfur dioxide on vegetation - critical levels (243kb PDF)
11. Effects of nitrogen-containing air pollutants - critical levels (391kb PDF)
12. Effects of ozone on vegetation - critical levels (314kb PDF)
13. Indirect effects of acidifying compounds on natural systems - critical loads (196kb PDF)
14. Effects of airborne nitrogen pollutants on vegetation - critical loads (332kb PDF)
Annex I List of Contributors (183kb PDF)
(*) 1987 evaluation retained, not re-evaluated
writes in a reference report of November 2006
..." Cleaning up our chemical homes , changing the market to toxic - free products " :.... Chemicals out of control. Hazardous substances that are commonly used as chemical additives in consumer products can migrate out of the product over time. These same chemicals are consistently found in breast milk and umbilical cord blood, which demonstrates their wide, uncontrolled and undesired dispersion. Greenpeace testing has shown that hazardous, man-made chemicals are also widespread in house dust, rainwater and the bodies of eels. These substances can cause a wide range of health effects, including effects on the reproductive system, immune system and impacts on the nervous system and behavioural development. Exposure of the unborn child to minute quantities of hazardous substances can result in permanent irreversible damage... "
Hoya and other plant collections are for sale on aleyagarden.com Plant care is available in various posts of this blog. Contact : firstname.lastname@example.org
- Air Cleaning Plants in Scientific Literature.
This link http://ntrs.nasa.gov/search.jsp provides technical reports written by Dr. B. C. Wolverton. Click on the "NASA Technical Report Server" link above. At the search window, type wolverton into the box to gain access to a number of reports (most are downloadable in PDF format).
BULTEAU G., 2004, Définition d'une méthodologie d'évaluation des procédés d'élimination des composés organiques volatils de l'air intérieur, Thèse de Doctorat en Sciences pour l'ingénieur, spécialité génie des procédés, soutenue le10/12/04, Université de Nantes, 228 p.
CORNEJO J.J., MUNOZ F.G., MA C.Y. & STEWART A.J.,1999, “Studies on the decontamination of air by plants”,Ecotoxicology, 8, p.311-320.
DINGLE P., TAPSELL P. & HU S., 2000, “Reducing formaldehyde exposure in office environments using plants”, Bulletin of Environmental Contamination and Toxicology,64, p.302-308.
GIESE M., BAUER-DORANTH U., LANGEBARTELSC. & SANDERMANN H. Jr., 1994, “Detoxification of formaldehyde by the spider plant (Chlorophytum comosum L.) and by soybean (Glycine max L.) cell-suspension cultures”, Plant Physiology, 104, p.1301-1309.
KORTE F., KXESITADZE G., UGREKHELIDZE D., GORDE ZIANI M., KHATISSASHVILI G., BUADZE O., ZAALISHVILI G.& COULSTON F., 2000, “Organictoxicants and plants (review)”,
Ecotoxicology and Environmental Safety,47, p.1-26.
RZEPKA M.A.,CUNY D., BULTEAU G., LAKEL A., CAZIER F., VAN HALUWYN C., 2005, “Accumulation and effects of formaldehyde in plants perspective for an use for indoor air
treatment ?”in: Third international conference on plants and nvironmental pollution; Lucknow, Inde, 28/11/05 - 2/12/05.
SCHMITZ H., HILGERS U. & WEIDNER M., 200, “Assimilation and metabolism of formaldehyde by meaves appear unlikely to be a value for indoor air purification”, New Phytologist,147 (2), p.307-315.
UGREKHELIDZE D., KORTE F.& KVESITADZE G., 1997,
“Uptake and transformation of benzene and toluene by
plant leaves”, Ecotoxicology and Environmental Safety, 37, p.24-29.
WOLVERTON B., C. & WOLVERTON J., 1992, Interior
plants and their role in indoor air quality : an overview, Wolverton Environmental Services.
WOLVERTON B. C., MCDONALD R. C. & MESICK H. H.,
1985, “Foliage plants for indoor removal of the primary
combustion gases carbon monoxide and nitrogen dioxide”
Journal of the Mississipi Academy of Sciences, 30, 1-8
Herbs, Spices, Hoya and other plant collections are for sale on aleyagarden.com Plant care is available in various posts of this blog. Contact : email@example.com