Houseplants are a great way to beautify a room: their colorful leaves and interesting shapes often provide the perfect natural counterpoint to man-made furniture and structures. But houseplants are more than just a bunch of pretty faces. According to research, they can help improve indoor air quality by removing pollutants known as volatile organic compounds (VOCs).

Plants’ ability to help us breathe easier indoors was first demonstrated in a two-year study conducted by NASA in the late 1980s. At the time, the agency was looking for houseplants to help clean the air in space facilities. The study examined the ability of 15 houseplants to remove three common indoor pollutants — the VOCs benzene, formaldehyde and trichloroethylene — from the air. Benzene is emitted from paints, synthetic fibers and plastics, among other sources. Formaldehyde is released from many sources, including foam insulation and plywood, and sources of trichloroethylene emissions include paints and varnishes.

Below is a list of 10 household plants that were found to be effective at removing VOCs in the NASA study:

Peace LilyPeace lily (Spathiphyllum wallisii) - This plant (at right), which does best when placed in a shady spot, can remove both benzene and trichloroethylene. It is poisonous, so keep out of the reach of children and pets. Also, avoid overwatering.

Golden pothos (Scindapsus aures) – This vine proved adept at filtering formaldehyde. It can be placed virtually anywhere in a home and requires a thorough watering about once a week.

English ivy (Hedera helix) – Effective at removing formaldehyde, this plant thrives in cool, moist air. It too is poisonous, so keep it away from pets and children.

Chrysanthemum (Chrysantheium morifolium) – This plant, which can produce wonderfully bright-colored flowers, can filter both benzene and formaldehyde. It does best in direct sunlight.

Gerbera daisy (Gerbera jamesonii) – Just like the chrysanthemum, this plant features bright flowers and requires lots of sunlight. It removes both benzene and trichloroethylene.

Mother-in-law's tongueMother-in-law's tongue (Sansevieria trifasciata 'Laurentii') – This hardy plant (at left) filters formaldehyde and doesn’t require a lot of maintenance.

Bamboo palm (Chamaedorea sefritzii) – The bamboo palm is effective at removing formaldehyde. Its soil should be kept moist, and it needs to be placed in indirect sunlight.

Azalea (Rhododendron simsii) – Effective at filtering formaldehyde, this popular plant does best in a cool environment (around 65 degrees) and out of direct sunlight.

Red-edge dracaena (Dracaena marginata) – Capable of growing up to 15 feet in height, this household plant is a good multi-tasker: it can remove both benzene and trichloroethylene. It is best suited for a temperature of 75 degrees or so.

Spider plant (Chlorophytum comosum) – This plant filters formaldehyde and doesn’t need a lot of upkeep.

It takes a village

To establish an effective plant-based air-pollution control system, you’ll need more than one plant in your home or office. The NASA study recommends using one potted plant per 100 square feet of home or office space. The plants also should be in containers with diameters of six to eight inches, the study urges.

With the advent of more energy-efficient homes and offices, which often reduce the flow of air between the inside and outside of a building, it makes more sense than ever to be concerned about indoor air pollution. By using the plants listed above, you can help create a healthy environment in your house or place of work.

For further reading:

Related air filtering plant story on MNN: 15 houseplants for improving indoor air quality

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Photos: Kasia/flickr/Flickr; Wikimedia Commons