Clear the air

Spring is glorious. We’ve spent the winter months poring over gardening catalogs, and now our seeds are sprouting under grow lights, and plans for planting are in full swing. It might also be a good time to think about placing plants inside your home.

Newer homes are often tightly sealed to trap climate-controlled air inside and avoid energy loss. But when heated or cooled air stays inside, so do harmful chemicals, resulting in what is often called “sick building syndrome.”

According to the EPA, concentrations of many volatile organic compounds (VOCs) are consistently up to 10 times higher indoors than outdoors. Exposure to VOCs can cause eye, nose and throat irritation; headaches; loss of coordination; nausea; liver, kidney and central nervous system damage; allergies; fatigue; and dizziness. Some VOCs cause cancer in animals. Some are suspected or known to cause cancer in humans.

Scores of familiar products emit VOCs, including paints, varnishes and lacquers; paint strippers; cleaning supplies; cosmetics; building materials and furnishings; office copiers and printers; correction fluid; and hobby and craft materials including glues, adhesives and permanent markers.

In the late 1980s, NASA and the Associated Landscape Contractors of America (ALCA) conducted a two-year study to determine how effectively 19 different houseplants removed common pollutants from the air.

NASA and ALCA tested primarily for three VOCs: formaldehyde, benzene and trichloroethylene. Formaldehyde is used in many building materials including particleboard and foam insulations. It is in many cleaning products and is added to permanent press clothing and draperies. Benzene, a known human carcinogen, is found in stored fuels and paint supplies, and automobile emissions. (Fumes from your garage can seep into your home.) Trichloroethylene is used in paints, adhesives, inks and varnishes. It is also used in dry cleaning. So when you bring home that newly cleaned silk blouse and fancy jacket, you’re also bringing home a VOC.

NASA’s study found that houseplants do indeed improve indoor air quality. It recommends having at least 15 different varieties in a home under 2,000 square feet, planted in pots that are at least six inches in diameter. Among the recommended plants are four varieties of dracaena, golden pothos, bamboo palm, Boston fern, Chinese evergreen, three varieties of philodendron, English ivy, spider plant, snake plant and weeping fig.

Kamal Meattle has also studied the effects of three varieties of houseplants on the air in his 20-year-old, 50,000-square-foot commercial building in New Delhi, India. The building houses 1,200 plants and 300 workers. His 15-year study indicates that when an individual spends 10 hours in the building, his/her blood oxygen goes up by one percent. Compared with other buildings, workers have 50 percent less eye irritation, 34 percent fewer incidents of respiratory ailments, 24 percent fewer headaches and an increase of 20 percent in productivity. He has created an air-cleaning system of massive banks of plants. As a result, his building uses 15 percent less energy.

For one’s home, Meattle recommends three plants: Areca palm, Snake Plant and Money Plant.

Areca Palm removes carbon dioxide and converts it into oxygen. He recommends four shoulder-height plants per person. Snake plants convert CO2 to oxygen at night, and so it is also called the Bedroom Plant. Meatlle suggests having six to eight waist-high plants per person. The Money Plant also removes volatile chemicals from the air.

Although many plants like light, they do not have to be placed near windows. It’s a good idea to set them away from drafts, which reduce their ability to clean the air.

Once your plants are situated around your house, take a deep breath. Then go outside to the garden.