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The Cause of Internet and TV Addiction?




·        Effects

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·        Fan-Assisted Planters

·        Personal Breathing Zones

·        Related Topics

·        Recommended Books



Negative Ions

"In nature, ions are formed in a variety of ways. About half are created by radioactive gases. Radioactive substances in the soil, cosmic rays, ultraviolet rays, air flow friction, falling water and plants all produce the other half. For example, they stream off the leaves of plants, most notably pines and asparagus ferns."

Ion & Light: Negative Ions, Vitamins of the Air?


"Sharp, pointy leaves worked best."

Newsgroups: sci.electronics.misc: Ionizers/Negative ion generators


"Plants that have the highest transpiration rates produce the most negative ions."

Wolverton Environmental Services: FAQ about Indoor Air Pollution


Air Purification

"The amount of leaf surface area influences the rate of air purification by plants.  Generally, the larger the plant leaf surface area, the higher the transpiration rate and the greater the surface area to absorb airborne chemicals."

Wolverton Environmental Services: FAQ about Indoor Air Pollution


"Our studies have shown that large numbers of indoor plants can reduce the levels of airborne microbes.   Although we did not measure negative ion levels, the reduction in mold spores and bacteria in the air surrounding those plants was most likely due to negative ions.  Our studies were published in 1996 in the Journal of the Mississippi Academy of Sciences {41(2): 99-105}

      Dr. Lohr from Washington State University also published a paper on how houseplants can reduce human stress and increase productivity.  {“Interior plants may improve worker productivity and reduce stress in windowless environments,” Journal of Environmental Horticulture, 1996, 14(2): 97-100.}   These effects are most likely due to increased negative ion levels in offices.

      Dr. Lohr published another paper entitled {“Particulate matter accumulation on horizontal surfaces in interiors: Influence of foliage plants,” Atmospheric Environment, 1996, 30(14): 2565-2568.   In this paper, Dr. Lohr demonstrated that houseplants could reduce the dust levels in a computer room by 20 percent.  This reduction was most likely from the production of negative ions."

Wolverton Environmental Services: FAQ about Indoor Air Pollution


"A two-inch (more or less) layer of gravel or other porous material on top of the soil will prevent mold growth."

Wolverton Environmental Services: FAQ about Indoor Air Pollution


"At least 300 volatile substances found inside many buildings, from detergents, gasoline, oils, plastics, rubber, synthetic fibres, tobacco, smoke, carpet, clothes, foam insulation, furniture, household cleaners, paper goods, dry cleaning, inks, lacquers, creosote, varnishes, adhesives, sealants, paints, partcleboard, plywood, timber treatments, are all potential causes of ailments in humans. Among the common ailments attributed to indoor 'offgassing' are

·        headaches,

·        asthma,

·        unnatural fatigue,

·        conjunctivitis,

·        chemical hypersensitivity syndrome and

·        chronic degenerative conditions.

     Since research indicates that people spend approximately 90 percent of their time indoors, and consume 15kg of air a day compared with 1kg of food, the maintenance of indoor air quality is an important step in avoiding the accumulation of toxins.

     Bill Wolverton was asked by Nasa back in 1973 to find a solution to maintaining air quality inside confined spaces such as space pods. He confirmed the common intuition that indoor plants regularly remove pollutants. Photosynthesizing plants and their roots and associated microorganisms act to break down contaminants which are then taken up as nutrients. He discovered that

·        Boston fern,

·        chrysanthemum,

·        dracaena and

·        Ivy

were highly effective at removing the formaldehyde, benzene and trichloroethylene from sealed chambers."

Living Soil: Indoor Tropical Plants can Detoxify Air


"The most commonly available plants [in England (British web site)] on this list are the

·        Boston Fern (Nephrolepsis exaltata),

·        Areca Palm (Chrysalidocarpus lutescens),

·        the Spider Plant (Chlorophytum comosum), and

·        English Ivy (Hedera helix).

Since different plants absorb different pollutants, a mix of a minimum of two plants per 100 square feet of floor space in an average home is recommended, but basically, the more the better."

Living Soil: Indoor Tropical Plants can Detoxify Air


Note: Boston ferns are sometimes called sword ferns.



·        Wolverton Environmental: Sources of Chemical Emissions


·        'Do temperature and humidity influence the ability of plants to remove airborne chemicals and microorganisms?'

·        'Mean Indoor Air Concentrations of Chemicals Found in Various Buildings'

·        'Removal of Formaldehyde from Sealed Chambers by Plants Grown in Potting Soil'

Wolverton Environmental Services: FAQ about Indoor Air Pollution


Fan-Assisted Planters

"To further enhance the natural cleansing properties of plants, Dr. Wolverton in association with Actree Corporation has developed and is marketing high efficiency filters that combine highly absorbent materials, UV light, an electrical fan and an interior plant.  These innovative filters have the VOC [volatile organic chemical, e.g. formaldehyde] removal capacity of approximately 200 regularly grown plants.  They are currently marketed in Japan under the name 'EcoPlanter.'   They should become available in the U.S. in the near future.  When they do become available, information on how to obtain them will be posted on this website.   So, check back often!"

Wolverton Environmental Services: Indoor Air Pollution


·        Actree Corporation: EcoPlanter (Japanese language; can be partially translated using Babel Fish Translation)


Personal Breathing Zones

"A personal breathing zone is an area of 6 to 8 cubic feet (0.17 to 0.23 cubic meters) [correction: should be feet instead of cubic feet, meters instead of cubic meters], surrounding an individual. These are usually areas where an individual remains for several hours, such as at a desk or computer, watching television or asleep. Plants placed within a personal breathing zone can add humidity, remove bioeffluents and chemical toxins, and suppress airborne microbes. These benefits are in addition to their aesthetic and psychological values. (Page 26)"

Book: Wolverton, B. C. How to Grow Fresh Air. Penguin Books, 1997.


Related Topics

·        Indoor Air Pollution: Negative Ions

·        Indoor Air Pollution: Positive Ions


Recommended Books

·        How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office

·        Wolverton Environmental Services



Back to 'Indoor Air Pollution'