Home

Design Guidelines

Projects

Articles

Links

 Nature’s Best Air Purifiers

 By Thomas Hirsch

Over the past year, we have addressed the most common indoor air quality (IAQ) threats:  offgassing of toxic building materials, building construction errors or poor maintenance causing excessive moisture and mold accumulation, electromagnetic fields, air tight building methods with inadequate fresh air exchange and inadequate ventilation of fossil fuel combustion gases.  Keeping our indoor spaces 100% pollution free with the freshest possible air is a difficult proposition.  As always, we need only to look towards nature for clues.

“Plants were an essential component of the evolutionary processes that converted the earth from a highly toxic environment into the living self-regulating system it is today.  Each living component; microbes, plants and animals, exist in a harmonious relationship with other life forms.  Oxygen produced during photosynthesis – the process by which green plants use sunlight to convert carbon dioxide and water for energy- is vital for all organisms that require oxygen for respiration.  The living processes of animals would deplete the atmosphere of oxygen if it were not replenished by photosynthesis.  Plant produced oxygen is carried over the earth’s entire surface by wind currents.  The wide diversity of plant life distributed throughout the world influences the creation of many micro-climatic zones.  Geography, biology and human intervention are all factors that greatly determine local environmental and climatic conditions.  For instance, the removal of trees and other vegetation from vast areas of land causes environmental changes in soil composition, weather patterns and air quality.” 1.

“The highest mission of plants is not merely to please our eyes with color, our mouths with delicious fruits.  Not only do they do this and more, but they are ever silently but surely eating up what is impure and injurious to ourselves in the atmosphere and in the earth all around our homes; and any dwelling in which plants are well and healthily grown will be more likely to be a clean and healthy house than if plants were not there.” 2.

When NASA began work on the Skylab and other space stations, they discovered that air quality was a major concern inside the closed facility.  Research detected over 300 volatile organic compounds (VOC’s).  In addition, bioeffluents released during human respiration, the presence of airborne microbes like mold spores and low relative humidity all contributed to poor air quality.  The Associated Landscape Contractors of America (ACLA) jointly funded research with NASA to evaluate the ability of common houseplants to remove VOC’s like formaldehyde, benzene and trichloroethylene from tightly sealed chambers.  The positive results were published in 1989 and led the ACLA to create the Plants for Clean Air Council (PCAC).  This non- profit organization continues to support the cultivation of plants as a method of improving air quality.

To further the air quality research in sealed chambers,  NASA developed a small, tightly sealed structure called the “Biohome.”  The interior was constructed of plastic and other synthetic materials and consequently many VOC’s were emitted.  “People entering the Biohome experienced typical symptoms associated with sick building syndrome, such as burning eyes and throat, and breathing problems.”1.

After the addition of indoor plants, individuals who entered the Biohome no longer experienced symptoms associated with sick building syndrome.

After the plant’s leaves absorb the airborne toxins, they are then delivered to the roots where they are broken down by soil microbes.  Soil microorganisms are air purifiers in their own right; they act as sponges to absorb gases and vapors like carbon monoxide from cigarette smoke.  This task is impaired if one uses synthetic, store bought plant fertilizers.  Microbial health depends on good organic soils and conditioners for vitality.  They are weakened or destroyed altogether by synthetic fertilizers.   “Plants also release phytochemicals that suppress mold spores and bacteria found in the ambient air.  Research findings show that plant-filled rooms contained 50-60 % fewer airborne molds and bacteria than rooms without plants.” 1.

In addition to air purification and oxygen production, plants provide still more benefits.  Plants have the ability to balance ions, modify temperatures and regulate humidity; especially important during the dry effects of indoor heating systems.  Scents and subtle fragrances of plants and flowers enhance air quality.  Indoor plants can be cultivated for food production.

The best fresh air has an ionic ratio of about 60:40; negative to positive ions.  These conditions are found in high mountains, waterfalls, wilderness forests and beaches.  Ever wonder why it feels so good to walk in these places?   Unfortunately, today’s building practices upset this ideal 60:40 ratio with the introduction of synthetic finishes and furnishings, low humidity and forced air furnaces, common wiring errors and certain mechanical devices.  (See Healing Garden Journal, June 2001 on Electromagnetism).   Using certain landscaping strategies like solariums, greenhouses, mini-forests or a pool with a fountain or waterfall can restore balance in air ionization.  Businesses have found increased employee productivity and morale and decreased absenteeism with the inclusion indoor plants and green spaces.   Rehabilitation health facilities have long recognized the healing benefits of solariums and greenhouses.

There is a mold phobia common among our people today and plants are sometimes seen to be a culprit.  Yes there are individuals with allergies to specific plant pollens and molds.  Not all plants trigger allergic responses.   It is best to test and remove the offending ones.  Mold is a different issue. See comments on mold above.  Even ultraviolet light from the sun (not through Low-E glass!) has been shown to reduce the mold count.  Obviously, those hypersensitive to molds should be cautious.

Biological Engineers or “Bioneers” have developed ways to use ecosystem dynamics to restore our natural (and unnatural!)  world.  John Todd, Ph.D., is a visionary biologist who designs “living machines” that mimic natural ecologies to purify sewage, septage and wastewater in greenhouses all in the pursuit to revitalize the health of the world’s water.  “ A living machine is like any other machine.  It accomplishes work.  Living machines can be designed to generate fuels, produce foods, convert wastes and undertake environmental repair.  Living machines can be designed to regulate the climate and air quality in buildings. Living machines can be designed to allow us to create ecological industrial parks, where manufacturing, food production and other forms of human activity can be integrated into holistic systems.  The basic engine of a living machine is sunlight.  Like the coral reef or the rainforest, the living machine has the ability to self-organize, self-design, self-repair, and self-replicate, like the great ecosystems themselves.  In other words, it is possible for us to think about technologies that can last for hundreds or even thousands of years.”  3. Hmm…sounds like sustainability to me.

We are living in an exciting time of discovery…and re-discovery.  Houses and neighborhood villages of the future could be “living machines” themselves or “living houses”  The possibilities are bright and endless.  For now, maybe it’s time to put the poinsettias aside, get out our seed flats and begin to “conjure up” our next gardens.  Breathe deep!

  References:

1)     How to Grow Fresh Air. Wolverton, Dr. B.C. Penguin Books, 1996                                                               

2)     Attributed to the Ladies Floral Cabinet, 19^th century

3)     From Eco-Cities to Living Machines; Principles of Ecological Design. Todd, John & Todd, Nancy Jack. North Atlantic Books,1994

4)     The Healthy House, Creating a Safe, Healthy and Environmentally Friendly Home.  Baggs, Joan & Baggs, Sydney. Harper Collins Publishers, 1996

5)     The Natural House Book, Creating a Healthy, Harmonious and Ecologically Sound Home Environment.  Pearson, David. Fireside Books, 1989

Harmony Home Construction, LLC.

8122 Barney Road     Traverse City, Michigan  49684
Ph: 1-877-45-GREEN     Fx: 231-932-9193
info@harmonyhomeconstruction.com