Indoor Air Quality in the Winter
Indoor air quality is often much worse than outdoor air. The
Environmental Protection Agency (EPA) estimates that indoor air pollutant levels
could be two to five times higher than pollution levels outdoors. Considering
that most Americans spend an estimated 90 percent of their time inside, indoor
air quality has a great impact on our everyday lives. In addition, indoor air
pollutants are one of the foremost triggers of allergies and asthma.
Why Winter Makes Indoor Air Quality Worse
Homes are built to be energy- (and therefore cost-) efficient by
holding heat in during the winter time and keeping heat out during the summer.
Winter weather prompts homeowners to tightly seal any cracks in insulation that
could allow cold drafts into the home. This, in turn, also seals off the home
from any fresh air and raises the concentrations of both allergens and
pollutants in the home.
Pollutant Sources in the Home
Pollutants in the home come from a variety of sources. The first
step in making sure that your family has the cleanest possible air is knowing
where the pollutants come from. Following is a list of common sources of indoor
Combustion sources such as oil, gas, kerosene, coal, wood. Any household
appliances that use any of these fuels can lead to indoor air pollution. Such
appliances include wood-burning stoves, fireplaces, water heaters, dryers, and
stoves. It's crucial to make sure that these appliances are well-maintained and
properly adjusted so that they don't release dangerous levels of pollution into
the home. Heating systems themselves are one type of combustion source. (Another
reason that indoor air pollution can be worse in winter.)
Building materials and furnishings, ranging from insulation, to carpeting, to
cabinetry or furniture made of pressed wood. The kinds of pollutants that these
items in the home may harbor or release are varied, including VOCs, mold, and
Household cleaning and maintenance products, personal care products; air
fresheners, for example, release pollutants continuously.
Hobby or home improvement activities including painting, varnishing, sanding,
welding, using adhesives, and more. Basically, if it produces fumes, it's
probably not good for you to be breathing it or filling your home with it,
especially when your home is sealed tight against winter cold - and the healthy
circulation of fresh air.
Outdoor sources like radon, pollen, lead, and more. Radon occurs in the soil as
the natural decay of uranium occurs and can leak into the home. Pesticides,
pollen, lead, and other outdoor pollutants may be tracked by people or pets into
the home, where their levels become concentrated.
Pets - animal dander and other particles from pets with fur or feathers are a
major aggravation of allergies and asthma to sensitive individuals. As people
stay indoors more, so do pets that go outside during less inclement weather.
Common Household Pollutants
The next step in making sure to protect your family from
household pollution is knowing what the pollutants are so that you can know how
to deal with them. Here is a list of the most allergens and pollutants that
affect indoor air quality.
Mold and mildew - when windows are closed tight against cold
air, steam from the bathroom and the kitchen, as well as other kinds of moisture
can build up in the home. Mold and mildew reproduce through spores, which become
airborne and easily inhaled.
Pet dander - because it is very light and very small, pet dander
is one of the most irritating and difficult-to-remove allergens. Indoor
concentrations are especially high during winter when pets, as well as people,
spend more time indoors.
Dust mites - because more time is spent indoors during the
winter, the concentration of dust mite food - shed human skin cells - increases,
as do dust mite populations. Dust mites are present wherever there is dust,
including household surfaces, upholstered furniture, draperies, carpets, and
Pollen - though less of a problem in the winter, there are
winter-blooming plants whose pollen can be tracked indoors. In addition,
fluctuations in weather may cause plants to blossom earlier than normal.
Biological pollutants - in addition to molds, pollen, dust
mites, and animal dander, other germs, viruses, and bacteria are present in the
Environmental tobacco smoke (ETS), or secondhand smoke, is also a major indoor
Formaldehyde is one of the main volatile organic compounds (VOCs), and is often
found in adhesives or other bonding agents present in carpets, upholstery,
particle board, and plywood paneling.
Various VOCs -in addition to formaldehyde, many other volatile organic compounds
(VOCs) are present in cleaning products, air fresheners, beauty products,
laundry products, and more. Off-gassing of VOCs from household items (like
dry-cleaned drapes or other clothing, or particle board furniture or cabinets)
is also a source of VOCs.
Asbestos comes from microscopic mineral fibers that are flexible and durable and
won't burn. They are extremely light and consequently can remain airborne and
therefore easily inhaled. Many home components contain asbestos, including
roofing and flooring materials, insulation, and heating equipment, among others.
These are only a problem if the asbestos is disturbed and becomes airborne, or
when it disintegrates with age.
Carbon monoxide and nitrogen dioxide are the worst air pollution components
given off by the combustion sources discussed above. Carbon monoxide is odorless
and colorless, and it interferes with the distribution of oxygen in the body.
Symptoms of carbon monoxide poisoning include poor coordination, headache,
nausea, confusion, nausea, dizziness, and fatigue; the gas can also worsen
cardiovascular conditions. High levels can cause death. Nitrogen dioxide is
similarly colorless and odorless, and it irritates the mucous membranes,
including those in the eyes, nose, and throat. Additional effects include
shortness of breath, damaged respiratory tissue, and chronic bronchitis.
Lead - lead can be present in the home as paint or dust. Older homes routinely
used lead paint, and cracked or chipping paint leads to both paint chips and
paint dust, both dangerous pollutants, especially if there are young children in
Effects of Poor Indoor Air Quality
Immediate effects of poor indoor air quality can show up after
just a single exposure and include headaches, dizziness, fatigue, and itchy
eyes, nose, and throat. Asthma and chemical sensitivities can also be aggravated
by exposure to indoor pollution. Chronic sensitivity may also build up after
Although it remains uncertain what levels or periods of exposure are necessary
to bring on serious health effects from indoor air pollution, long-term effects
of indoor air pollution include respiratory disease, heart disease, and cancer.
Improving Indoor Air Quality
The EPA recommends three basic strategies to improve
indoor air quality: source control,
ventilation improvements, and air cleaners or purifiers.
Improving indoor air quality through source control involves removing the
sources of pollution. Gas emissions, like those from a poorly maintained stove,
for instance, can be adjusted in order to lower their emissions; asbestos can be
sealed or enclosed. Often, source control is a more cost-conscious way to remedy
poor air quality than ventilation because increased ventilation can
significantly increase energy costs.
However, increased ventilation is an easy and effective way to control poor
indoor air by bringing fresh indoor air into circulation. Especially because
most heating systems do not bring fresh air into the home, opening windows and
doors when weather permits provides great benefit.
You can easily check to see if your home might have ventilation problems.
Condensation on walls or windows, stuffy air, moldy areas, or dirty heating or
cooling equipment are all indicators. Odors (which are most notable upon
entering the home from outdoors) are also an indication of poor ventilation.
When performing many home improvement or hobbies, it's especially important to
be aware of the need for proper ventilation. Without ventilation, pollutants
such those emitted during painting, welding, sanding, or even cooking, can add
toxic elements into your home environment.
The EPA's final recommendation in their three-pronged approach to improving
indoor air quality involves using an air purifier. When investing in an air
purifier, it's important to understand all the factors involved. For instance,
most air purifiers capture particulate matter but do not remove gas and other
chemicals. Activated carbon filters are needed in order to remove gas and
chemicals. Additionally, it's important to get an air purifier that has the
proper capacity to fill the job. This depends on factors such as pollutant
levels, sensitivity, and room size.
Here are a few tips for maintaining healthy indoor air, especially during the
Clean regularly - dusting safely with proper cleaning equipment
like dust cloths and masks, and regular and frequent vacuuming go a long way in
reducing airborne pollutants like mold, pollen, pet dander, and dust mites.
Replace furnace filters frequently - with your heating unit
running during the cold winter months, your furnace filter is working hard to
keep your air clean. Ensure that airflow is not impeded - or worse, that
contaminants aren't being reissued into the air you breathe - by checking your
filters regularly and replacing them as needed.
Test for radon - the Surgeon General warns that radon causes
lung cancer and recommends testing your home. The EPA's Web site has more
information about testing for radon.
Consider purchasing a carbon monoxide detection device to alert
you to the presence of this colorless, odorless, lethal gas.
Use non-toxic cleaning products. Especially when cleaning in the
winter when ventilation is typically less, chemicals' fumes stay inside the home
and on surfaces cleaned with them.
Keep bedding clean. Wash bedding frequently (once a week) in hot
water or with a de-mite laundry additive. Cover mattresses and pillows with dust
Look for low- or no-VOC products when doing any hobbies or
home-improvement projects. If possible, wait for spring, when you can open the
windows for adequate ventilation.
Dry cleaning products emit chemicals like formaldehyde from
dry-cleaned fabrics. Consider dry cleaning alternatives or air out dry-cleaned
items in the garage or patio before bringing them indoors or into your closet.
Air out and clean mold-prone areas of the home. Make sure
bathrooms, kitchens, and basements, which tend to collect extra moisture and may
not receive adequate ventilation, are routinely aired out, and cleaned of any
Open windows and doors when you can. If you're concerned that
outdoor pollutants may enter your home, use a window filter.
Air purifiers equipped with HEPA filters do an excellent job of
filtering particulate contaminants from the air. Carbon filters are necessary in
order to remove gases, odors, and chemicals from the air.
Many plants are known as nature's air purifiers because of their
ability to absorb toxins from the air. Just be aware that mold often grows
around plants, especially if they're watered often.
Knowing the sources of indoor pollutants, as well as what they
are and how to combat them, is the first step in keeping the air in your home
clean. Due to the combined factors of more time spent indoors and decreased
ventilation, winter is a time to be particularly vigilant about maintaining
healthy indoor air quality. But making sure that your home is as free as
possible from indoor pollutants is important all year round.
Scott Smith is an expert on indoor air quality and
air purifiers at achooallergy.com.
If you are looking for a
Boulder County heating contractor please call us today at 303-800-HEAT(4328) or complete our online service request form.
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