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Houseplants Help Filter Harmful Air Pollution

Posted: September 16, 2009

Houseplants can neutralize harmful ozone, making indoor air cleaner, according to a new study.

Ozone, which is the main component of smog, forms when high-energy light, such as the ultraviolet light from the sun, breaks oxygen bonds, ultimately resulting in O3, three atoms of oxygen joining together. When formed higher up in the atmosphere, the ozone layer protects us from harmful UV rays. Ground-level ozone is not so pleasant.

While indoor ozone is a bigger problem in many developing countries, owing to the burning of biomass for cooking and heat in poorly ventilated quarters, the colorless gas can infiltrate from outdoors into offices and homes even in developed countries. In addition, copy machines and printers, along with other equipment, can boost ozone concentrations indoors, the researchers say.

Leafy air filters

To figure out if green plants can clear the indoor air, Dennis Decoteau of Penn State's Department of Horticulture and his colleagues placed three common houseplants—a snake plant, a spider plant and a golden pothos—into chambers in a greenhouse. Ozone was then injected into the chambers at 10 times normal indoor amounts and concentrations were measured every few minutes until they were reduced to about 3% of the initial amount.