During these cold winter months, many of us spend more time indoors than outside and miss out on all the benefits of fresh air and sunshine. When this happens the quality of air in our homes and workplaces becomes even more important. Some common indoor air toxins can compromise our health without our even knowing they’re present, while others cause foul odors or irritate our eyes and sinuses.
When it comes to air quality, many homes and buildings today are built all wrong from the ground up. Builders start with man-made construction materials and then add synthetic flooring, laminated counter-tops, and wallpaper coated with plastic, not to mention the chemical adhesives that hold it all together. These materials “off-gas” pollutants into the air, and while modern insulation and other methods of energy conservation have reduced our fossil fuel consumption, they’ve also trapped these pollutants inside. “Sick Building Syndrome” can be the result when toxins such as formaldehyde, benzene, trichloroethylene, and carbon monoxide build up indoors and affect the health of those who live or work in the building.
Formaldehyde is found in virtually all indoor environments, from foam insulations to floor coverings, as well as in many cleaning products, paper products, and permanent-press clothing. It can cause allergic dermatitis; irritation of the eyes, nose, and throat; headaches; asthma; and possibly throat cancer. Benzene is commonly found in oils, paints, plastics, and rubber. It is a known skin and eye irritant, but may also contribute to chromosomal aberrations and leukemia. Long term exposure to even low levels of air-borne benzene causes headaches, nausea, drowsiness, nervousness, psychological disturbances, anemia, and bone marrow diseases. The National Cancer Institute considers trichloroethylene a potent liver carcinogen, but it continues to be present in paints, adhesives, inks, and varnishes.
Amazingly, a number of household plants are highly effective at reducing indoor air pollution and also help balance internal humidity within your home or workplace. We owe NASA for discovering much of the science behind these benefits—while investigating methods for maintaining clean air for astronauts in future space stations, their researchers found that houseplants did much more than just add beauty to the indoor environment.
NASA’s conclusions are not surprising if you consider where these houseplants come from. Because many evolved beneath the dense canopy of taller trees in tropical or sub-tropical forests, they had to make do with relatively little light and learned to photosynthesize highly efficiently. This efficiency extends to their processing of gasses in the air, making them super air scrubbers. When a plant’s soil is exposed to air, its natural micro-organisms get better and better at absorbing and using air-borne pollutants as food. You can boost this process by removing any lower leaves on your plants that cover the soil surface. Growing your plants in containers at least 6 inches in diameter will also increase their effect.
But to maximize your plant’s air cleaning abilities even more, consider re-potting into an aeration container.
Aeration containers are soft-sided fabric containers that, as the name implies, provide aeration to your plant’s soil and root system. They are extremely convenient for indoor plants because they won’t break if you drop them, can be thrown in the washing machine in between uses, and are collapsible for easy storage. Despite this, when filled with soil they hold their shape as well as a ceramic or plastic pot and are strong enough to support even large trees. In fact, commercial tree growers have been using aeration containers for decades.
But by far their greatest advantages are the benefits they provide to your plants. Besides helping your plant clean the air, aeration containers can “air prune” the plant’s root structure. Typically a potted plant’s roots will grow until they reach the side of their container and then circle around the side of the pot, resulting in a “root bound” plant that cannot be transplanted even when it outgrows its container. Eventually these circling roots can cause strangulation of the plant. But in an aeration pot, roots reach the side of the container and then stop growing in length, instead developing a multitude of fine root branches. A highly branched root structure means a greater root mass, and a greater root mass produces a plant with more (and more beautiful) flowers and foliage, more resistant to insects and disease.
Aeration containers make plant care easier too. You won’t have to worry about over-watering when you use an aeration pot. Its porous fabric allows excess water to drain and evaporate from not only the bottom of the container, but also all of the sides. This is a significant advantage to anyone interested in cleaning their indoor air but nervous about caring for plants—especially since the most common mistake resulting in potted plant death is over-watering.
When it comes to choosing houseplants for improving air quality, several varieties stand out above the rest. English Ivy, palms like the Bamboo Palm or Reed Palm, Green Spider Plant, Golden Pathos, Mother-In-Law’s Tongue, and Chinese Evergreen are all excellent air scrubbers. Many philodendron varieties are as well, including the Heart Leaf, Selloum, and Elephant Ear Philodendron. Also look for Dracaena varieties, like the Warneck, Red-Edged, Janet Craig, and Cornstalk Dracaena. Flowering plants that clean the air include the Gerbera Daisy, and Pot Mums. Some houseplants are poisonous and not appropriate for homes with pets or small children but would be fine for the workplace—be sure to consider who may be exposed to your plants before making a choice.
As a rule of thumb, one houseplant is recommended for every 10 square yards of floor space in your home or workplace. (This assumes a ceiling height of 8-9 feet.) Thus, if your living room is 12’ x 15’, the décor should include at least 2 houseplants. A 1,800 square foot house should have 20 houseplants within to achieve optimal air quality benefits. (You can do the math for your own home—one square yard is equal to 9 square feet.)
Many people mistakenly believe that indoor plants require direct sunlight to thrive, but because most were originally native to tropical forests where they grew beneath the dense shade of towering trees, a dark corner of your home is just fine for many houseplants. Some research shows that when plants are placed in a draft their air cleaning abilities are reduced, so ventilation may be the greater concern when choosing where to place your plants.
Removing indoor pollutants from our homes and workplaces is always important, but the winter months are a perfect time to focus on improving indoor air quality. There are some toxins inherent to modern building and building maintenance practices that damage our health without our even realizing it. The fact that we can reduce this risk simply by bringing beautiful plants indoors is a testament to the power of nature and a year-round gift to both yourself and your family.
*Kate Liebar is co-owner of Green Thumb Garden Center, an organic and all-natural garden center in Downtown Ferndale. You can find her at www.greenthumbferndale.com. She encourages everyone to purchase their houseplants and potting supplies from a locally-owned nursery or garden center.