In recent articles I have reviewed the all too common problem of indoor air pollution. Ventilation, one of the best antidotes, was acknowledged to be tricky for city dwellers whose outdoor air is polluted. Fortunately, nature provides an ideal purification system, plants.
In the late 1960s, Agent Orange leaked into local waters near Elgin Air Force Base in Florida and was creating a public health crisis. B.C. Wolverton, a scientist helping the military clean up environmental messes around biological warfare centers, was called in. His team discovered swamp plants that were eliminating Agent Orange from the water.
Fascinated by this finding, Wolverton joined NASA who was attempting to create sustainable closed environments. In 1973, 107 volatile organic compounds (VOCs) were identified inside the Skylab space station. Synthetic materials used in constructing the lab (that are now found in homes and offices) were off-gassing VOCs, such as formaldehyde, benzene and trichloroethylene. These compounds are irritants and potential carcinogens. In the air-locked inner sanctum of the lab, the astronauts got sick.
You don’t have to get onto the space station to have this experience. The same conditions have been created in our homes and offices. In the 1970s, the energy crisis introduced a new design ideal, the airtight building. These structures promised a dramatic increase in energy efficiency by holding temperature-controlled air in place. Strangled air circulation gave birth to the Sick Building Syndrome.
Rather than abandoning synthetic materials or reducing energy efficiency, Wolverton sought to hack nature’s life support system, plants. His success is documented in scores of research papers. To summarize and simplify, Wolverton demonstrated how plants give off water vapor that pulls contaminated air down to the soil where the roots detoxify and convert pollutants into plant food.
In 2006, Wolverton’s ideas were put to the test on a grand scale. Following the devastation of Hurricanes Katrina and Rita, the Federal Emergency Management Agency (FEMA) created temporary housing for more than 150,000 people. Residents of these FEMA trailers complained of respiratory problems, asthma, and rashes. Air testing revealed high formaldehyde levels off-gassing from particle board construction material. A planter designed by Wolverton successfully cleansed the air.
Kamal Meattle, a researcher in New Delhi, became fixated on pollution after his doctors told him he was allergic to the air. He had lost 30% of his lung capacity. Building on Wolverton’s work, he directed the construction of a green office park using three species of air-filtering plants.
Areca Palm, “the living room plant” (Chrysalidocarpus lutescens), removes carbondioxide and converts it into oxygen. Mother-in-law’s Tongue, “the bedroom plant” (Sansevieria trifasciata), converts carbondioxide into oxygen at night and Money Plant, “the specialist plant” (Epipremnum aureum) removes formaldehyde and other VOCs.
Numerous studies conducted by the Indian government revealed that these plants did more than eradicate pollutants and eliminate health problems associated with sick building syndrome. Human productivity increased by over 20% and energy requirements decreased by 15%.
Plants have a lot to teach us.
Because they can’t move away from environmental threats, they have developed a magnificent arsenal of adaptive responses to such stressors as UV radiation (sunlight), fluctuations in hydration, soil nutrients and temperature, infections and a wide spectrum of toxins. These responses have been honed over approximately one billion years, a span that dwarfs our tenure on the planet.
It is no coincidence that one third of the top 20 drugs on the market are plant-derived. In eating plant foods, we benefit from the compounds they make in response to their stressors. We now know that being surrounded by plants provides more than an pleasing aesthetic.
The significance of this story is larger than plants and pollution. Our assignment as a species, if we are to live well, is to recreate essential elements of the environment that made us in the environment that we have made.