With the push in last thirty years toward greater energy efficiency and tighter building practices, and the increased use of synthetic materials and furnishings, air circulation and quality has suffered in both homes and office buildings. This has even led to the coinage of a condition known as “Sick Building Syndrome”, when occupants may experience chronic irritation of the eyes or respiratory system when in a “sick” building. The uncomfortable irritaion experienced in these buildings is the result of off-gassing from common synthetics such as plastics, adhesives, and preservatives emitting toxic chemicals into the air. The most common culprits – VOCs like formaldehyde and trichloroethylene – are also known carcinogens and come with many household furnishings such as carpets particle -board furniture.
Thankfully, the most common of house plants have been shown to absorb and neutralize these harmful chemical emissions, even dramatically. Part of NASA’s reasearch included the BioHome, a closed space built entirely of synthetic materials, which induced the most common symptoms of Sick Building Syndrome. When common house plants were added to the space, testing showed almost a complete removal of the VOCs and no symptoms of SDS. In simplified terms, the house plants emit a water vapor during photosynthesis which creates a vacuum drawing the impure air down around the plant roots to be taken up and converted to food or neutralized in the soil. Wolverton’s later research shows that the more air circulation a plant has, the better it becomes at purifying contaminated air. Other researchers have shown the additional benefits of keeping multiple plants indoors to include increased oxygen levels at night related to improved sleep, medical patients healing faster when surrounded by living greenery, and improved mood and productivity in workplaces with plants.
All this to say that Grandma might have been on to something with all of her hanging spider plants and ivy. Designers are now taking this further to include seamless outdoor-indoor spaces, rooftop gardens as a component of HVAC systems, and living window screens. For the common urbanite, changes can be as simple as adding a few decorative potted plants, especially inside. The NASA-funded research recommends 15-18 plants per 1,800 square feet, which can easily be accomplished at the rate popular houseplants tend to propogate. Many of the plants we have included below are very low-maintenance and tolerate low light conditions, perfect for the small apartment and busy professional.
When selecting indoor plants for your home, be sure to consider children and pets as some varieties may be poisonous. Always ask a local nursery to be sure what you are getting and how to care for it before purchasing or taking cuttings from a friend. Varieties to avoid include the Poinsettia family (Euphorbiaceae), the Philodendron family( Araceae), and Oleander (Nerium oleander). Although beautiful, these can be deadly for pets and small children if swallowed.
Below is a list of common contaminates and their sources identified by NASA, and the plants that most efficiently removed the toxins from the air in their testing.
Mother-in law’s tongue
Janet Craig dracaena
Stepladder plant shelf from Hasselfors Garden