Could a House Plant Clean the Air?

As English ivy climbs, airborne contaminants fall, study finds

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By Randy Dotinga
HealthDay Reporter

THURSDAY, Nov. 10, 2005 (HealthDay News) -- Want a great, green way to clean the air in your house?

A new study by a California teenager suggests that a not-so-usual suspect -- the English ivy plant -- might be just the ticket.

Ryan Kim, the son of an allergy researcher, found that an English ivy plant does a significant job of cleansing the air of mold particles and other nasty particulates, including canine fecal matter.

"This may be a better alternative, and more cost-effective" than an electronic air purifier, said study co-author Hilary Spyers-Duran, a nurse practitioner and investigator at West Coast Clinical Trials in Long Beach, Calif.

But an indoor-pollution specialist is skeptical of the plant-as-air-cleaner approach. He suggested that concerned residents try an old-fashioned method: ridding the house beforehand of contaminants that make the air dirty.

Some house plants, including English ivy, have been touted for their air-cleaning properties. But it hasn't been entirely clear how effectively they work, said Spyers-Duran, who wrote the paper with Kim, the son of her company's CEO, Dr. Kenneth Kim.

The younger Kim put moldy bread and dog feces in individual containers and measured how many particles spread into the air. Then he put an English ivy plant into the containers to see what happened, and then repeated the experiment.

The study findings were released this week at the annual meeting of the American College of Allergy, Asthma and Immunology in Anaheim, Calif.

According to the study, the plant reduced airborne particles of fecal matter by an average of more than 94 percent over 12 hours. The level of mold in the air went down by 78.5 percent.

How does a plant manage to clean the air? "Aerosolized proteins are actually absorbed through the roots and soil of the plant," Spyers-Duran explained.

So should health-conscious Americans rush out and buy an English ivy plant? There are a few caveats, experts said. For one thing, English ivy is toxic and shouldn't be placed near small children or pets. Also, the study only examined what the plant does in containers, not in entire rooms.

Then there's the matter of allowing dirt into your home. The soil that feeds a plant also sends out its own potentially dangerous microbes and waste products, noted Jeffrey Siegel, an assistant professor of civil engineering at the University of Texas at Austin.

Siegel, who specializes in indoor air quality, recommends that residents combat indoor pollution by getting rid of sources within the home. This includes making people smoke outside and providing exhaust hoods to get rid of cooking-related pollutants.

If that doesn't work, he said, air purifiers with HEPA filters are a good approach. He doesn't recommend the use of ionizing air purifiers, which some researchers suspect actually boost levels of the pollutant ozone.

Which air purifier is best? In another study released at the allergy conference, researchers at West Coast Clinical Trials found that the Honeywell HEPA purifier did the best job out of three purifiers tested. Tested in two mold-infested houses, it cleared 72 percent of mold particles in one house in one hour and 84 percent of mold particles in the second house in one hour. The Living Air purifier only cleared 43 percent and 50 percent in one hour, respectively, while Sharper Image's Ionic Breeze purifier only managed to clear 28 percent and 16 percent in three hours, the researchers said.

More information

Learn more about the controversy over air purifiers from Consumer Reports.

SOURCES: Hilary Spyers-Duran, R.N., F.N.P., nurse practitioner, Allergy, Asthma & Respiratory Care Medical Center, and investigator, West Coast Clinical Trials, Long Beach, Calif.; Jeffrey Siegel, Ph.D., assistant professor, civil engineering, University of Texas at Austin; presentation at American College of Allergy, Asthma and Immunology annual meeting, Anaheim, Calif., Nov. 4-9, 2005

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