Did you know the EPA ranks indoor air pollution as one of the top five threats to human health? Indoor air pollution is associated with numerous ailments including asthma, headaches, chemical hypersensitivity and even cancer. In large part because of chemicals that outgas from items such as furnishings, finishes and household cleaners, indoor concentrations of many pollutants are two to five times greater than outdoor levels. This is particularly concerning because many newer buildings are more efficiently sealed in the interest of energy efficiency, and most people spend up to 90 percent of their time inside.
Fortunately, we can count on nature to be our health ally when it comes to creating healthier indoor air. In the late 1980s, NASA researchers studied the ability of houseplants to purify the air and remove toxic agents such as benzene (in glue, paint and auto fumes); formaldehyde (in particleboard, paper and carpets); and trichloroethylene (in paint stripper and spot remover). They released a list of air-filtering plants, and subsequent studies have shown similar benefits of houseplants. For example, researchers at Penn State University proved that three common houseplants—snake plant, spider plant and golden pothos—all reduced ozone in a simulated indoor environment. Grow the following plants in your home or office to breathe easier.
Aloe Vera: This purifying plant from South Africa is shown to clear the air of benzene and formaldehyde, both known human carcinogens. Unlike most plants, aloe actually releases oxygen and absorbs carbon dioxide at night, making it ideal for bedrooms. Aloe gel is also medicinal, used externally to treat burns and internally for numerous ailments. It is a sun-loving plant; beware of overwatering it.
Areca Palm: This palm, native to Madagascar, is among the best plants for removing a variety of toxins, especially formaldehyde. It likes bright, indirect light. Because of a high transpiration rate, it adds a lot of humidity to the air and needs to be watered regularly. This plant does not tolerate neglect; its tips will turn brown when moisture, light, temperature and fertilizer levels are not ideal.
Dracaena ‘Janet Craig’: This is one of the best plants for clearing formaldehyde and trichloroethylene. Although native to tropical Africa, this plant adapts well to indoor environments and can even endure some neglect. It likes moderate to bright indirect light. Water after the soil begins to dry out, and use a pot with drainage holes to avoid soggy soil.
Dragon Tree: Native to Madagascar, this tree can grow up to 6 feet tall and is among the best plants for removing xylene, trichloroethylene and toluene (the latter is a solvent and additive to gasoline). This is another one of many houseplants belonging to the Dracaena genus and comes in four main varieties. It likes moist soil at all times, but not soggy soil. Keep the plant in semishade, and avoid strong, direct light.
English Ivy: An excellent choice for removing formaldehyde, benzene and even airborne fecal matter, this native of Asia, Europe and North Africa is somewhat difficult to grow indoors. It prefers moist air, so mist leaves regularly when humidity is low and keep in bright light. Beware that the leaves are poisonous to pets and humans when ingested.
Ficus ‘Amstel King’: Adept at clearing formaldehyde and a good general air purifier, the new ficus cultivar Ficus alii is rapidly gaining popularity. Native to Thailand, this plant is related to weeping fig, but less finicky and with long pointed leaves. Water thoroughly, allowing the top half-inch of soil to dry out between waterings, and provide bright, indirect light.
Gerbera Daisy: This lovely plant from Africa adds a splash of color to the room and removes a variety of chemical vapors from the air, notably formaldehyde and benzene. It makes a delightful plant in the summer garden, and if brought indoors in the fall, it may continue to flower through the winter. This is a relatively difficult indoor plant that requires bright light and moderate temperatures.
Peace Lily: This lily is adept at removing a variety of alcohols and chemical vapors, including acetone, benzene, ammonia, formaldehyde and xylene, and it scored among the top plants tested for removing several toxins. This easy-to-grow lily can raise humidity levels by up to 5 percent, a helpful feat in dry climates. They enjoy semisun to semishade and being watered a lot at once, then being allowed to dry out.
Rubber Plant: This handsome houseplant from southeast Asia, known botanically as Ficus elastica, is near the top of the list for removing formaldehyde. Under proper conditions, a rubber plant can reach a height of 8 feet. Rubber plant is extremely forgiving. Ideally, it prefers bright, indirect light; regular watering; and mist on its leaves when the air is dry.
Snake Plant (also known as mother-in-law’s tongue): Native to West Africa, this evergreen perennial clears smog, formaldehyde and trichloroethylene from the air. Like aloe, the snake plant produces oxygen and removes carbon dioxide at nighttime, making it ideal for bedrooms and other low-light rooms. This plant can withstand considerable neglect and infrequent watering.
Spider Plant: This flowering perennial is native to Africa and removes smog, formaldehyde, benzene and xylene—found in auto exhaust, synthetic perfume and paint. A NASA study found this plant can remove 96 percent of the carbon monoxide and 99 percent of the nitrogen dioxide within a sealed chamber. This resilient plant thrives in a variety of environments. It prefers medium to bright light, but avoid extended amounts of direct sun.
Weeping Fig: These popular tropical trees, known botanically as Ficus benjamina, are excellent at removing a variety of pollutants, including formaldehyde, xylene and toluene. They come in three main varieties: a bush, a standard tree and a braided tree with entwined trunks. Weeping fig has a tendency to drop its leaves when moved. They enjoy full to semisun and moist soil.
4 Benefits of Indoor Plants
Higher Oxygen Levels: During photosynthesis, plants absorb carbon dioxide and release oxygen. Plants add oxygen to indoor air during the day. At night, most absorb some oxygen and release carbon dioxide. A few types of houseplants release oxygen at night—mainly succulents, moth orchid, dendrobium orchid, snake plant and bromeliads—making them ideal companions for the bedroom.
Lower Mold and Bacteria Counts: A home filled with lots of houseplants has 50 to 60 percent fewer mold spores and bacteria. Houseplants emit substances called phytochemicals that suppress these microbes in indoor environments.
Improved Mood: Studies from the University of Technology in Sydney, Australia, found that indoor plants reduce anger by 44 percent, anxiety by 37 percent, fatigue by 38 percent and depression by 58 percent. Amazingly, just one plant can make a difference.
Natural Humidifier: Plants release moisture through their leaves. Use plants to keep indoor air within the ideal humidity range. Palms and ferns in particular have high transpiration rates. Most indoor plants prefer higher humidity and may need their leaves misted with water for optimum health.