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Is Your Home's Air Unhealthy? Try Plants

Plants Can Remove Harmful Indoor Airborne Contaminants, Study Says

By Bill Hendrick
WebMD Health News

Reviewed By Louise Chang, MD

Dec. 4, 2009 -- Certain plants can remove dangerous airborne contaminants commonly found in homes, new research suggests.

The contaminants plants can remove from the air include harmful volatile organic compounds such as benzene, toluene, octane, alpha-pinene, and trichloroethylene (TCE), the researchers say in a study published in the August issue of HortScience.

Of 28 indoor plants tested, Stanley Kays, PhD, of the University of Georgia and his horticultural team identified five "super ornamentals" that had the highest rates of contaminant removal, a process called phytoremediation.

These are the red ivy (Hemigraphis alternata), English ivy (Hedera helix), variegated wax plant (Hoya cornosa), asparagus fern (Asparagus densiflorus), and the purple heart (Tradescantia pallida), the study says.

The scientists placed the plants in glass, gas-tight containers, exposing them to common volatile organic compounds found indoors. And the plants did a good job of removing the airborne contaminants.

Researchers say there may be thousands of plants capable of removing airborne contaminants.

Volatile organic compounds are likely wafting about in every house, Kays tells WebMD. They're given off by home furnishings, carpets, plastics, cleaning products, building materials such as drywall, paint, solvents, adhesives, and even tap water, Kays says.

The pollutants have been linked to many illnesses, including asthma, cancer, and reproductive and neurological disorders, and claim 1.6 million lives a year, he says, attributing that number to the World Health Organization.

Air inside homes and offices is often a concentrated source of such pollutants, in some cases up to 100 times more polluted than outdoor air, Kays tells WebMD.

No one yet knows why some plants are effective at remediation, but he and other scientists are digging for answers.

"We also want to determine the species and number of plants needed in a house or office to neutralize problem contaminants," he says in a news release. "The idea that plants take up volatile compounds isn't as much of a surprise as the poor air quality we measured inside some of the homes we tested."

There is no affordable way for average consumers to determine the air quality of their homes, Kays says.

He tells WebMD that not all volatile organic compounds are toxic, and that some plants emit toxins, too. But placing some common ornamentals indoors has the potential to improve air quality, he says.

"In reality, you are much more in danger from these compounds inside than outside," he tells WebMD. "All houses have these compounds. Even computers give them off. It would be advantageous then to have a few plants in your house. They also keep humidity at fairly constant levels."

But there is no magic list on the horizon, he says.

"You might have some plants that are good with benzenes but not with formaldehyde, which comes from upholstery, carpet, a lot of sources," he tells WebMD.

Hopefully, he says, in a few years there will be an affordable test that can alert people to the contaminants in their homes, and a list of the best plants to help clean the air.

"Ideally, we'd have an extension service that would send out a packet that would do the test for you to send back and get recommendations," he tells WebMD.

He says scientists in Korea are "substantially ahead of us in phytoremediation research," and one with whom he is collaborating, Kwang Jin Kim, PhD, of the National Horticultural Institute in Seoul, has evaluated the ability of 86 species to remove indoor formaldehyde.

SOURCES: News release, University of Georgia.

Yang, D. HortScience, August 2009; vol 44.

Stanley J. Kays, PhD, The Plant Center, University of Georgia.

USDA web site: PLANTS Database.

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