While trying to become informed on how to minimize my family’s exposure to toxins in our home, I have been completely overwhelmed by the number of toxic sources within a home: mattresses, shower curtains, paints, electronics, carpets, building materials, dust,… the list is endless. So when I recently heard on CNN’s Toxic Childhood by Dr. Sanjay Gupta that plants will help indoor air quality, I was intrigued and went online!
Online, there were a number of references to a NASA study that proved that plants would be effective in detoxing chemicals from synthetic materials… Really?! NASA studies plants?
NASA’s Plant Studies
In the 1970s, in researching a way to create a breathable environment for a NASA lunar habitat (a moon base), NASA scientists — led by Dr. B.C. Wolverton — began to study the feasibility of a closed ecological life-support system. Analysis of the air inside the spacecraft proved that air quality would be a major concern. The presence of more than 300 volatile organic chemicals (VOCs) was detected in the air inside the spacecraft during occupancy by its crew.
Eventually, in 1980, NASA’s John C. Stennis Space Center discovered that houseplants could remove VOCs from sealed test chambers. In 1984, NASA published its research results that demonstrated the ability of plants to remove formaldehyde from test chambers.
Because formaldehyde is the most commonly found toxin in indoor air, the ability to remove this substance from the air was used as the standard for rating these plants.
Numerous sources of formaldehyde are present in the buildings we inhabit. It is found in various resins and is used to treat many consumer products, including garbage bags, paper towels, facial tissues, fabrics, permanent-press clothing, carpet-backing, floor-coverings and adhesives. Formaldehyde is released by gas stoves and is found in tobacco smoke. It is also used in building materials such as plywood, particle-board and paneling. Both plywood and particle-board are used extensively in the manufacture of domestic and office furniture and fittings.
Numerous adverse health problems have been ascribed to formaldehyde exposure, ranging from well-documented effects such as eye, nose and throat irritation, to more controversial claims including asthma, cancer, chronic respiratory diseases and neuropsychological problems. Although evidence of cancer formation in rodents exposed to formaldehyde is unequivocal, the extrapolation of these results to humans has been controversial.
Studies have shown that plants play a major role in delivering airborne toxins to microbes living around their roots, which can then break down the toxin. The adaptation of microbes to this task is the key to houseplants becoming better fighters against air pollution.
– How To Grow Fresh Air: 50 Plants That Purify Your Home or Office (1996) by Dr. B.C. Wolverton; pages 23 – 24
Dr. B.C. Wolverton discovered that houseplants are the best filters of common pollutants such as ammonia, formaldehyde, and benzene. Hundreds of these poisonous chemicals can be released by furniture, carpets, and building materials, and then trapped by closed ventilation systems, leading to the host of respiratory and allergic reactions now called Sick Building Syndrome.
Background on Dr. B.C. Wolverton
In the late 1960s, B.C. “Bill” Wolverton was an environmental scientist working with the U.S. military to clean up the environmental messes left by biological warfare centers. At a test center in Florida, he was heading a facility that discovered that swamp plants were actually eliminating Agent Orange, which had entered the local waters through government testing near Eglin Air Force Base. After this success, he wanted to continue this line of research and moved to what was at the time called the Mississippi Test Facility, but is now known as NASA’s Stennis Space Center.
He was funded by the Space Agency to research the environment’s natural abilities to clean itself as part of what is now Stennis’ Environmental Assurance Program. The goals were to clean the Center of chemicals left behind through wastes and to supply information to NASA engineers about closed-environment “eco” support that may prove helpful in designing sustainable living environments for long-term habitation of space.
The first step for Wolverton’s research was to continue the remediation work he had started with the military. He was tasked with using plants to clean waste water at the NASA Center. To this day, Wolverton’s design, which replaces a traditional septic system with water hyacinths, is still in use. His research then turned to using plants to improve air quality.
In 1973, NASA scientists identified 107 volatile organic compounds (VOCs) in the air inside the Skylab space station. Synthetic materials, like those used to construct Skylab, give off low levels of chemicals. This effect, known as off-gassing, spreads the VOCs, such as formaldehyde, benzene, and trichloroethylene, all known irritants and potential carcinogens. When these chemicals are trapped without circulation, as was the case with the Skylab, the inhabitants may become ill, as the air they breathe is not given the natural scrubbing by Earth’s complex ecosystem.
Around the same time that Wolverton was conducting his research into VOCs, the United States found itself in an energy crisis. In response, builders began making houses and offices more energy efficient. One of the best ways to do this was to make the buildings as airtight as possible. While keeping temperature-controlled air in place, this approach reduced circulation. Combined with the modern use of synthetic materials, this contributed to what became known as Sick Building Syndrome, where toxins found in synthetic materials become concentrated inside sealed buildings, making people feel sick.
The solution Wolverton sought was not to make indoor environments less energy efficient or to move away from the convenience of synthetic materials; rather, the plan was to find a solution that restores personal environments. The answer, according to a NASA report later published by Wolverton in 1989, is that “If man is to move into closed environments, on Earth or in space, he must take along nature’s life support system.” Plants.
How To Grow Fresh Air: 50 Plants That Purify Your Home or Office (1996) by Dr. B.C. Wolverton
Dr. Wolverton published his findings about using plants to improve indoor air quality in dozens of technical papers while with the Space Agency and as a simple consumer-friendly book, How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office. In it, he explains how plants emit water vapor that creates a pumping action to pull contaminated air down around a plant’s roots, where it is then converted into food for the plant. He then goes on to explain which plants and varieties remove the most toxins, as well as to rate each plant for the level of maintenance it requires. The book has now been translated into 12 languages and has been on the shelves of bookstores for nearly 10 years.
Modern scientific research indicates that the indoor environment may be as much as ten times more polluted than the outdoor environment? The US Environmental Protection Agency (EPA) currently ranks indoor air pollution as one of the top five threats to public health. Yet millions of people fail to realize the serious nature of the problem, or even worse, fail to recognize that there is a problem. Today, people living in industrialized societies spend as much as 90 percent of their lives indoors.
– How To Grow Fresh Air: 50 Plants That Purify Your Home or Office (1996) by Dr. B.C. Wolverton; page 8
Conclusion
I found the book to be interesting, informative, and it provided helpful guidance in identifying houseplants to get for my home as well as tips on how to care for them. I’m convinced and have already started buying plants for our home! The key challenge now will be keeping my plants alive!!
{ 3 comments… read them below or add one }
I’ve been very interested in this topic and so glad you posted. Recently we bought a plant for my daughter’s room. Fun for her to learn to care for and good for her health.
One point about your posting.
Sick Building Syndrome IS very real and exists today. And it doesn’t just make people feel sick, it can cause serious health problems. My sister got asthma from working in a school with toxic air quality. She has to take several medications for rest of her life. People need to be aware of this vicious type of situation.
Thanks so much for sharing an example of Sick Building Syndrome. I had not come across anyone who had experienced it.
Dr. Wolverton worked with U.S. Health Equipment Co., Inc. to develop a new Plant Air Purifier. The planter uses a houseplant to circulate at 10′ x 18′ room in one hour. Dr. Wolverton’s research has allowed one plant to have the effect of over 100 houseplants grown in soil. Look for the Plant Air Purifier on Facebook and Twitter, website coming soon!