While many people realize the star power of live plants to convert carbon dioxide to oxygen, plants have other hidden talents. Plants in buildings can clean the air and optimize humidity levels.
According to a June study by the Building Owners and Managers Association (BOMA) International, “Presently, 29 percent of the national economy—its GDP—is housed within office buildings.” Additionally, according to a National Human Activity Pattern Study in the 90’s, Americans (on average) spend 87% of their time indoors and 6% in an enclosed vehicle. These are impressive numbers, and while working inside a building seems like a great environment, safe from the extremes of weather and motor exhaust, buildings, especially new construction or remodels, are not as friendly as they appear.
Over recent decades, the building industry has reduced energy consumption and become ‘greener’ with improved insulation and less outdoor air transfer. This, unfortunately, reduces indoor air quality as building materials, carpeting, furniture, and even people expel volatile organic compounds (VOCs), and humidity levels reach extremes. VOCs in the air, such as formaldehyde and benzene, can cause sore throats, headaches, and respiratory irritations leading to reduced worker productivity through distraction, reduced efficiency, and absenteeism. Low humidity is associated with colds, allergic attacks and asthma while high humidity can be problematic for furniture, equipment, and people.
Tropical plants are especially efficient at combating some of these problems. Because they are understory plants in their native environment, they must be very efficient at capturing light. They are also very efficient at processing gasses. Leaves absorb VOCs and digest or translocate them to their roots. Transpiration (water vapor emitted through leaves) also moves water from the soil surrounding the roots up through the plant. Air is then moved down around the roots pulling pollutants into the soil. There the plant converts the pollutants into a nutrient it uses. This movement of air facilitates plants in removing toxins from their surroundings. And since HVAC often dries the air, higher transpiration rates speed the cleaning process while emitting water vapor to optimize humidity levels between 35 – 65%.
A landmark study in the 80’s by NASA and the Associated Landscape Contractors of America suggested that one or two plants every 100 square feet could have a positive effect on internal air quality, not to mention their aesthetic and calming value.
by Greta M. Ivanovic