Most Americans live and work in buildings awash in chemicals blamed for asthma, lung cancer, and a host of other maladies.
The best way to clean the air could be with a green thumb, according to Bill Wolverton, a former NASA environmental scientist who has spent more than 30 years studying how plants purify the air. The results of his research could come to market this fall as a household air filter that looks like a potted plant.
"Every chemical we tested, plants could take them out," said Wolverton, who originally worked on life support systems for the moon and Mars.
Plants absorb and convert airborne poisons to energy and food. At the roots, ever-adapting microbes munch on toxicants.
Wolverton worked to enhance those processes and has licensed his technology to Phytofilter Technologies, an upstate New York state startup. It's creating potted plant air filters to sell for several hundred dollars each later this year.
The device has a fan at the base of a plant pot, drawing and trapping toxins near the roots, where hungry microorganisms dwell. A version has been sold in Japan for seven years as the EcoPlanter, which includes a mold-killing ultraviolet light.
The self-cleaning filter is supposed to pack the purifying power of more than 100 plants and destroy poisons that are only trapped by carbon, zeolite, and high-efficiency particulate air, or HEPA, filters.
Phytofilter founder Martin Mittelmark also developed a plant-based filtration system for a building at Syracuse University this spring, backed by funding from the Environmental Protection Agency.
In recent years, air quality tests by the University of Technology in Sydney, Australia, found that levels of toxins in offices shrank by 75 percent with the presence of only six plants per room.
Wolverton thinks his technology on a larger scale could clean the exhaust from power plants by trapping air pollution in water, then feeding it through a closed system of marshes. A similar tactic taken by small towns in Mississippi turns sewage into fertilizer by diverting it through marshes. But Wolverton sees more interest coming from developing nations including China and India.
"Universities in the U.S. are geared up to use mechanical means to clean up the environment, and when you mention plants to some of these engineers, that's sissy to them," he said.
For now, Wolverton plans to give away plant filters to residents of formaldehyde-polluted trailers in areas still recovering from Hurricane Katrina. The technology cut formaldehyde levels by one-sixth in trailers from the Federal Emergency Management Agency, in tests he explored with the Sierra Club.
Common building products and furniture are also laced with formaldehyde and toxins including flame retardants. And scientists increasingly link chemicals in consumer electronics to myriad health woes.
The World Health Organization blames bad indoor air for nearly 3 percent of diseases. Americans spend 90 percent of their time indoors, where air is more polluted than outside and can contain more than 900 volatile organic compounds, or VOCs, according to the EPA.
"The newer, more energy efficient buildings are sealed tighter and create more of a problem because chemicals offgas from practically everything in them," Wolverton said.
"Green" buildings might use paints and varnishes without VOCs, which don't release headache-inducing fumes. But standards for green buildings too often overlook the use of plants, Wolverton said. "You need plants to act as lungs in buildings."
Several plants in a 200-square-foot space will improve the air in most rooms, according to Wolverton, who recommends potting in inert pebbles or clay mix rather than soil, in which mold can grow.
Based upon chemicals in common consumer products, for instance, a peace lily might be ideal for a laundry room, and a new couch could be flanked by bamboo palms. Among the plants researchers found to have potent air-purifying qualities are the Eureka palm, lady palm, peace lily, and rubber plant.
However, people with curious cats or dogs might beware of lilies, poinsettas, and other plants that may poison them. The Pet Friendly House lists plants that won't hurt pets who chew on their leaves.