purifierThere’s a reason why most science-fiction interplentary ships contain artificial gardens. They not only provide food and oxygen, but they are nature’s perfect air filters. Microorganisms associated with the plants are present in the potting soil, and these microbes are also responsible for much of the cleaning effect. No less than NASA has scientifically determined that common indoor plants are effective in removing many air-borne toxins.  Before you head out to purchase a room or home air purifier costing hundreds (or thousands) of dollars, you may want to consider spending far less on far more effective air purifiers — house plants,

Despite these products’ claims, there’s little definitive medical evidence that air purifiers help to relieve respiratory symptoms.   Before you buy an air purifier, try some simple, common-sense steps to reduce indoor air pollution. Begin by vacuuming often, banning smoking indoors, minimizing use of candles and wood fires, and using exhaust fans in kitchen, bath, and laundry areas. Consumer Reports (among others) reports that while some of the better air purifiers can help remove dust, tobacco smoke, and pollen. other types of gaseous pollutants, however, are another matter. Some portable models with carbon pre-filters are claimed to filter VOCs, known respiratory irritants that arise from adhesives, paints, and cleaning products. But the Environmental Protection Agency warns that such filters are specific to certain gaseous pollutants, not for others, and that no air purifiers are expected to remove all gaseous pollutants found in the typical home. Carbon filters also must be replaced often, typically every 3-6 months, or they stop working–and can even, when full, release trapped pollutants back into the air. http://www.consumerreports.org/cro/air-purifiers/buying-guide.htm Indoor air pollution does present a health concern.

In fact, the Environmental Protection Agency (EPA) now ranks indoor-air quality among the five top threats to human health. The problem is worse in winter, when we spend the most time sealed in our homes and offices.Given that people spend more than 90 percent of their time indoors, air quality matters . Furnishings, upholstery, synthetic building materials, and cleaning products in homes and offices can emit a variety of toxic compounds, like formaldehyde. Indoor air pollution can also be caused by pollen, bacteria, and molds, as outdoor air contaminants like car exhaust finds its way into buildings. All of these are made worse in small or poorly-ventilated spaces (like maybe your apartment with that window that you accidentally painted shut last year).

But expensive air-filtration systems are not the only solution….nor even an optimal one. Adding potted plants to a room has been shown to reduce the amount of air particulates (although plants in bloom may be contributing their own compounds to the air) and simple houseplants can filter many dangerous chemicals out of indoor air. The plants’ leaves absorb and destroy certain volatile organic compounds, while the microbes that live around the plants’ roots convert chemicals into a source of food and energy for themselves and their host plant. The following plants are exceptionally effective at cleaning the air.

Boston Fern is hardy, easy to find and fairly easy to grow.
Areca Palm (Chrysalidocarpus lutescens) also is known as yellow palm or butterfly palm.
Lady palm (Rhapis excelsa) is one of the most effective houseplants for improving indoor-air quality.  An added benefit; it is highly resistant to most insects.
Rubber plant (Ficus robusta) is a hearty plant with thick, leathery, dark green leaves. It will tolerate limited light and cool temperatures and is very effective at removing chemical toxins from indoor air—the best of the ficus genus yet tested.
Dracaena “Janet Craig” (Dracaena deremensis “Janet Craig”) is a pest-resistant leafy plant that can live for decades. It will tolerate poorly lit areas, though its growth will be slowed. Favor the “Compacta” variety, which grows to one to three feet in height, not the regular variety, which requires more care and can reach 10 feet if not pruned.
Peace Lily (Spathiphyllum sp) produces beautiful white flowers, making it one of a relatively small number of plants that bloom reliably indoors.
English Ivy (Hedera helix) is best known as a ground cover, however it also grows very well in indoor hanging baskets. One big bonus is that it adapts well to a wide range of indoor conditions.  However, English Ivy does not do well in high temperatures.
Bamboo Palm is also easy to find and grow, but needs bright light.
Garden Mum offers reliable flowers in addition to its air-cleaning leaves.
Snake Plant  (very hardy)
Pothos (Epipremnum aureum) tolerates neglect and low light and is extremely resistant to insects. They come in numerous shades of green and yellow, characterized by its heart-shaped leaves. It usually is grown in hanging baskets, but it also can climb.
Corn Plant (Dracaena fragrans “Massangeana”) is so named because its leaves look like those of corn stalks, not because it actually produces corn. It tolerates low light, though it prefers bright light.
Syngonium (Syngonium podophyllum) produces arrow-shaped, green-and-white or green-and-silver leaves.

As a rule of thumb, one to two good-sized plants from the list above per 100 square feet of interior space tend to be sufficient. There’s no health downside to having more plants than this as long as mold doesn’t develop in the potting soil.

Growing plants in hydroculture significantly increases their ability to clean the air. With hydroculture, plants are grown in watertight containers and rooted not in potting soil, but in expanded clay pebbles sold for this purpose at some garden stores. All of the plants listed above will grow in hydroculture, and the Peace Lily, in particular, thrives when grown this way. Hydroculture also reduces the risk that fungal spores, mold and soil-borne pests will develop on houseplants. Plants grown in hydroculture need a complete fertilizer that contains micronutients.

An added solution to indoor air pollution is hardwood floors. Carpets collect dust and other allergens, and not even the best vacuum can remove them all. For people who suffer from severe allergies, switching from carpets to wood or tile floors can be like flipping a switch from chronic bad health to good. That’s particularly true in the winter, when we spend more time inside with the windows closed.   But the best solution is probably the lowest cost and most natural one — our green, leafy outdoor neighbors.