Over thirty years ago, NASA began researching methods of air purification in space crafts to pave the way for long-term human space flight. The study, found here, concluded that many common houseplants are highly effective at removing toxins such as benzene, formaldehyde, ammonia, xylene and trichloroethylene. The findings have been replicated many times over. Their relevance today is unmistakable, especially given the number of man-made products which off-gas chemicals in our homes and workplaces, current energy-efficient construction practices, our focus on healthy living and concern for the environment.
The following are answers to commonly asked questions about the relationship between clean air and indoor plants.
How exactly do plants clean the air?
Plants are effective at absorbing gases through pores on the surface of their leaves. It’s this skill that facilitates photosynthesis, the process by which plants take in carbon dioxide and release oxygen. In effect, all plants can purify the air to some extent, but some do a better job than others.
Studies show that plants can absorb many gases, including a long list of volatile organic compounds (VOCs). Benzene (found in some plastics, cloth and pesticides) and formaldehyde (found in some cosmetics, dish detergent, fabric softener and carpet cleaner) are common indoor VOCs that plants help eliminate.
Plant roots and the microorganisms that live in healthy soil also absorb VOCs and other pollutants.
Which plants were used in the NASA study?
Most were common, easy to care for plants which you may have in your home or office right now. Top “air filters” included: Peace lily (Spathiphyllum wallisii), golden pothos (Scindapsus aures), mother in law’s tongue (Sansevieria trifasciata ‘Laurentii’), bamboo palm (Chamaedorea sefritzii), dracaena (Dracaena marginata), spider plant (Chlorophytum comosum), English ivy (Hedera helix), Chinese evergreen (Aglaonema commutatum). Gerbera daisies (Gerbera jamesonii) and potted mums (Chrysantheium morifolium) are also effective air purifiers, but tend to be short-lived flowering houseplants.
Can plants reduce the harmful effects of cigarette smoke in the air?
Cigarettes contain formaldehyde, one of the toxins that plants can remove from the air. However, the plant/cigarette smoke connection was not the focus of the NASA study. A 2010 study by the American Society of Horticulture Science found that ferns were among the most effective plants in formaldehyde removal. Check out the study for specifics on which ferns offer the best results.
Do I need to live in an indoor jungle to reap benefits?
Hardly! Studies found that approximately one 6″ to 8″ pot per 100 square feet, or 15-18 plants per 1800 square foot house makes a measurable difference. The more vigorous the plant, the more pollutants it will draw from the air.
Photo credits: Bing free images
Written by: Linda McDonnell, a Denver County Master Gardener