Houseplants may take some (light) work to keep alive, but they can work for you too: some plants help you breathe cleaner air in your home. Years ago, NASA tested a variety of indoor plants for their ability to remove pollutants from the air. They found that a number of them actually did clean the air of contaminants, providing a low-cost—not to mention appealing —solution to cleaner, fresher air in your home.
The Chemical Culprits
In the study, called “Interior Landscape Plants for Indoor Air Pollution Abatement,” scientists placed a single plant within a chamber and injected chemicals in the air; they collected air samples after a full 24 hours to see how much of each chemical remained.
Three common indoor air pollutants were tested: benzene, often found in gasoline, ink, oil, paint, plastics, and rubber; formaldehyde, found in consumer paper products (such as facial tissues or paper towels), household cleaners, and cigarette smoke; and trichloroethylene, found in ink, paint, lacquer, varnish, and adhesives.
The top ranking houseplants in NASA’s study included the Chrysanthemum, English Ivy, Peace Lily, Dracaena, and Gerbera Daisy.
- Chrysanthemum (Chrysanthemum morifolium)
- English Ivy (Hedera helix)
- Peace Lily (Spathiphyllum “Mauna Loa”)
- Dracaena deremensis
- Gerbera Daisy (Gerbera jamesonii)
Also known as Dendranthema x grandiflora, pot mum or florist’s mum , these perennials boast a rainbow of colors: yellow, amber, orange, red, lavender, violet, and white. Chrysanthemums are normally found outside during autumn, but they are also hearty indoor plants. Just make sure to give them lots of sun in rich, well-drained soil. Chrysanthemums are highly effective in removal of all three of the toxic chemicals tested by NASA.
It may be an invasive plant in some areas but when it’s contained indoors, it’s a purifying wonder. English ivy, which does well in low to medium light, can be pruned regularly to keep it to a manageable size. Plant in a container that drains easily, and water the plant thoroughly; wait until the soil is dry for a depth of a half an inch before watering again. English Ivy is particularly effective in removing Benzene from the air, though somewhat less effective than other plants in removal of formaldehyde and trichloroethylene.
Peace lilies, which feature long leaves and white flowers, are among the easiest plants to grow indoors. They require moistened soil at all times and fertilization every six months. The flowers bloom throughout the year, but for stubborn plants, try placing it in a room with less sunlight; the plant actually requires shade. The Peace Lily evidenced high effectiveness in removing trichloroethylene and benzene from the air, and was less effective than other plants in removal of formaldehyde.
These African-native plants have long, pointed grayish-green leaves with a broad stripe around the edges, and can grow up to 10 feet. An attractive and low-maintenance plant, they require shade and moderate watering—though take care not to over-water. Two cultivars of this plant were tested in the study: The Warneckei (also spelled Warneckii) and Janet Craig. The Dracaena is most effective in removing formaldehyde, though it does indicate a higher rate of removal of benzene than many other plants.
Daisies are bright, colorful, and full of air-cleaning power. One of the few flowery plants on NASA’s approved list, Gerbera daisies—available in red, orange, yellow, and cream —scored just as well as the plants with broad, green leaves. The flowers can actually last quite a while, though it is recommended that they be kept a maximum of three years. They do well with bright light, though it is best to keep them out of direct sunlight.