The ravages of winter drive us inside, where we take comfort in a warm home well protected and insulated from the elements.
But while a weather-tight home is great for saving energy and resources, that efficiency often comes at the expense of indoor air quality.
When the windows are closed for the season, a variety of indoor air contaminants can accumulate and bother residents. Some of these contaminants are allergens such as mold spores or dust mites. Others are toxic organic compounds off-gassing from furniture, building materials or carpets.
Dr. Jonathon Bayuk, medical director of allergy services at Allergy and Immunology Associates of New England, says there are many things homeowners can do to clean indoor air.
Air purifiers can remove allergens and other air contaminants, including dust mites, smoke and mold particles. Bayuk advises buying one that is big enough for the area of the room and uses a HEPA filter to trap contaminant air particles. He cautions against products that utilize blades. This type of air purifier creates ozone by generating tiny electrical sparks when the blades strike a contaminating particle. While each spark generates a minimal amount of ozone, over the course of a day, the ozone can accumulate to toxic levels.
Mold spores are a common indoor allergen. Bayuk says different kinds of mold can grow in homes, particularly in more humid areas of the house, such as the basement or in bathrooms. Many people find that using a dehumidifier can be helpful, particularly in the summer, to keep mold growth at bay.
Keeping the relative indoor humidity below 50 percent helps to discourage mold growth, according to Bayuk, but it’s important not to let humidity drop too low as dry skin can often become a problem when relative humidity drops below 35 or 40 percent.
Mold growing on a hard surface, such as a tub, can be relatively easy to clean (Bayuk recommends a solution of one part bleach to 10 parts water). However, porous objects, such as a box of books in the basement, may need to be disposed of in order eliminate that source of mold spores in the home.
Dust mites are another common indoor allergen that can cause year-round problems for people with a sensitivity to the enzymes they excrete.
Dust mites feed on the dead skin cells that humans and pets naturally shed, as well as dust, pollen and other organic material. They live in areas where they can find food, sufficient moisture and warmth.
Carpets, couches, and mattresses are common areas where dust mites live and breed. As these surfaces are porous, they gather below the surface of the fabric, making it difficult to get rid of them.
Bayuk says a mattress cover is a great place to start in curbing dust mites. The cover is made of a very tight fabric the mites cannot penetrate. Cleaning the cover on a weekly basis keeps them from piling up on these surfaces.
Reducing clutter and keeping a house clean can also reduce the number of dust mites. Bayuk recommends using a high-efficiency vacuum with a HEPA filter to remove mites and their food sources from carpets and sofas.
Dust mites are fairly easily removed from hard surfaces as they stick to a damp cloth. Bayuk says using a feather duster is virtually useless, and simply moves the mites and the particles they feed on to another surface.
Organic compounds off-gassing from dry-cleaned clothes, and from newly applied paints, lacquers and varnishes, as well as from newer furniture, carpets and building materials are another source of indoor air pollution.
In the late 1980s, NASA conducted a series of experiments to see if indoor plants could be used to purify the air of future space habitats. The agency’s final report on the experiments showed that some of the most common and easily cared-for houseplants were surprisingly effective at decreasing levels of the most common organic compounds found circulating indoors.
Hadley Garden Center stocks many of the plants named in the study. Greenhouse manager Angela Karlovich is familiar with the NASA study, and can lead customers to a wide variety of air-cleaning plants that perform well in a wide variety of indoor settings.
Karlovich says that many of the plants cited by NASA can thrive in low-light conditions, which makes them versatile and easy to care for indoors, including:
Dracaena: Several varieties were tested by NASA and were found to be effective at removing trichloroethylene (TCE), benzene and formaldehyde.
Spider plants: effective at removing formaldehyde. Spider plants are also non-toxic to pets.
English ivy: removes TCE, benzene and formaldehyde
Chinese evergreen: removes formaldehyde and benzene
Bamboo palm: removes TCE, benzene and formaldehyde. Bamboo palm is non-toxic to pets.
Golden pothos: removes formaldehyde
Philodendron: removes formaldehyde
Peace lily: removes TCE, benzene and formaldehyde
While sun-loving Gerbera daisies are usually planted outside, these plants removed the most TCE and benzene of all the plants tested at NASA. They are also non-toxic to pets.
Bayuk says like all plants, those mentioned above also add to indoor air quality by converting carbon dioxide into oxygen.