Houseplants are a great way to add color and life to a room, but did you know that some houseplants can actually improve your indoor air quality? Research published in 1989 by NASA and the Associated Landscape Contractors of America (ALCA)—now known as PLANET (Professional Landcare Network)—revealed that common household plants can help remove harmful indoor air contaminants including formaldehyde, benzene, and trichloroethylene.
The NASA/ALCA study was originally intended to discover ways to purify air during extended stays in orbiting space stations. With increased interest in and construction of energy-efficient homes, the study seems more relevant now more than ever. The reason being that energy-efficient homes are often tightly sealed to avoid losing energy from heating and cooling systems. However, this tight sealing doesn’t just lock in heating and cooling—it traps pollutants produced by the synthetic building materials used in modern-day construction.
For example, benzene is commonly found in oils and paints, formaldehyde is a common ingredient in particle board and foam insulations, and trichloroethylene can be found in paints, adhesives, inks, and varnishes. The presence of these pollutants and others can result in Sick Building Syndrome. According to the the Environmental Protection Agency (EPA), Sick Building Syndrome describes “situations in which building occupants experience acute health problems and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified.” In other words, contaminants in your indoor environment can “mysteriously” make you feel sick.
For two years, NASA/ALCA researchers studied 19 common household plants. Household plants were chosen over other plant species for their ability to adapt to tropical areas, where plants must survive in low sunlight. This characteristic means that they are exceptionally efficient at processing gases necessary for photosynthesis. Thus, they also have the potential to effectively absorb other gases, including harmful indoor air pollutants.
The study resulted in the identification of a list of the top 15 household plants for improving indoor air quality:
- Oxycardium Philodendron, heartleaf philodendron, Philodendron scandens
- Elephant Ear Philodendron, Philodendron domesticum
- Massangeana, cornstalk dracaena, Dracaena fragrans
- English Ivy, Hedera helix
- Spider Plant, Chlorophytum comosum
- Janet Craig, Janet Craig dracaeana, Dracaena deremensis
- Warneckii, Warneck dracaena, Dracaena deremensis
- Weeping Fig, Ficus benjamina
- Golden Pothos, Epipiremnum aureum
- Peace Lily, Mauna loa, Spathiphyllum
- Selloum Philodendron, Philodendron selloum
- Chinese Evergreen, Aglaonema modestum
- Bamboo or reed palm, Chamaedorea sefritzii
- Snake Plant, Sansevieria trifasciata
- Red-edged Dracaena, Dracaena marginata
For best results in average homes under 2,000 square feet, NASA/ALCA study researchers recommend using at least 15 samples of a large variety of the aforementioned plants. Study researchers also recommend that plants be grown in six-inch containers or larger.
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