HARDWORKING PLANTS
by: Linda Bray
President, Plants a la carte
October 2001

We can all readily appreciate how plants instantly bring life and beauty to commercial spaces. Clients and staff can feel the sense of warmth, stability and long term commitment of a company when surrounded by plants complementing the décor and design of a professional environment. As we, as interiorscapers, install new plants and containers, we constantly hear comments such as, "Now I feel we are in a real office". Plants add aesthetic value and a psychological feeling of wellbeing for most anyone or any place.

NOT JUST BEAUTY QUEENS
But there is so much more to what plants do for us! Evidence has been published that demonstrates how plants contribute directly to our physical health by cleaning our air, particularly in airtight office buildings. Most people may realize that plants help boost levels of oxygen and relative humidity. They absorb carbon dioxide and produce oxygen and transpire moisture as they photosynthesize light for energy. In addition, scientific studies have produced statistics supporting the premise that plants alleviate the symptoms of "Sick Building Syndrome". Researchers with the National Aeronautics and Space Administration (NASA) have concluded that live plants can effectively filter contaminants from our indoor environment as part of their research on using plants to clean the atmosphere inside space stations.

In the late 1970s, buildings were designed for maximum efficiency in heating and cooling to help alleviate the spirally energy costs. Super-insulation and reduction of fresh air exchange were two major contributors to reducing costs. But as the office buildings have become more airtight, the re-circulated air contains more pollutants from office equipment, furnishings, carpets, cleaning solvents, etc. People can feel the effects by experiencing headaches, drowsiness, respiratory irritations, achiness, increased asthma or fatigue which can reach debilitating level. Often people find the symptoms improve when they leave the buildings which we can't attribute completely to just getting out of work!

THE BIG BAD THREE
The NASA study, "Interior Landscape Plants for Indoor Air Pollution Abatement", conducted by Dr. Bill Wolverton, was released in 1989. The research demonstrated that interior plants and their potting media act as air filters, removing trace organic pollutants from the air. They measured the beneficial effects of specific plants on reducing levels of chemicals such as benzene, formaldehyde and trichloroethylene. These are the major pollutants known as the "The Big Bad Three". Benzene is present in plastics, inks, paint, synthetic fibers and detergents. Formaldehyde is emitted from pressed wood, foam insulation, carpeting, paper towels and cleaners. Trichloroethylene is in inks, paints, adhesives, varnishes, lacquers and dry cleaning solutions. The World Health organization estimates that approximately 30% of new and remodeled buildings contain enough pollutants to make employees ill. Dr. Wolverton found that plants could reduce concentrations of the "Big Bad Three" pollutants up to 90%.

NATURE'S HUMIDIFIERS
In addition to the problems with the sea of pollutants in our re-circulated air, the relative humidity in our heated buildings contributes to health hazards. Our sensitive membranes in our noses and throats are irritated, making us more susceptible to allergic reactions. Further study by Dr. Wolverton (Wolverton and Wolverton 1996) has shown that indoor plants do a better job of humidifying the air than electronic humidifiers through transpiration of mineral-free moisture. The substances emitted by the plants appear to suppress airborne levels of mold spores and other harmful microbes. As we horticultural technicians carry and pour gallons of water on your plants we realize the majority of that water will evaporate or be pumped right through the plants' systems, transpired into the air, raising relative humidity.

Dr. Wolverton has recommended that one to three plants per 100 square feet can significantly clean the surrounding air. He has tested 40 indoor plants and measured the effects on specific pollutants. Some of the big cleaners are plants very familiar to us interiorscapers and possibly to you: philodendron, pothos, bamboo palms, dracaenas, snake plants and spathiphyllums. Even poinsettias are good cleaners (and not toxic either but that is the subject of another article).

So perhaps the most compelling reasons for having plants in our workplace environments are the invisible ones. They can reduce the allergy-like reactions to the inevitable pollutants circulating in our airtight offices. As plants beautify our surroundings, they are adding to our health and letting us breathe a bit easier.