Air Quality in the Home
Quick Facts...
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Indoor air quality can be worse than that of outdoor
air.
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Problems can arise from moisture, insects, pets,
appliances, radon, materials used in household
products and furnishings, smoke and other sources.
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Effects range from minor annoyances to major health
risks.
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Remedies include ventilation, cleaning, moisture
control, inspections, and following manufacturers'
directions when using appliances and products.
Research has shown that the quality of indoor air can be
worse than that of outdoor air. Many homes are built or
remodeled more tightly, without regard to the factors
that assure fresh and healthy indoor air. Our homes
today contain many furnishings, appliances and products
that can affect indoor air quality.
Signs of indoor air quality problems include:
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Unusual and noticeable odors.
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Noticeable lack of air movement.
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Dirty or faulty central heating or air conditioning
equipment.
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Damaged flue pipes or chimneys.
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Un-vented combustion air sources for fossil fuel
appliances.
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Presence of molds and mildew.
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Health reaction after remodeling, weatherizing,
using new furniture, using household and hobby
products, or moving into a new home.
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Feeling noticeably healthier outside.
Common Sources of Air Quality Problems
Poor indoor air can arise from many sources. At least
some of the following contaminants can be found in
almost any home:
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Moisture and biological pollutants such as molds,
mildew, dust mites, animal dander and cockroaches
from high humidity levels, inadequate ventilation,
and poorly maintained humidifiers and air
conditioners.
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Combustion products, including carbon monoxide, from
un-vented fossil fuel space heaters, un-vented gas
stoves and ovens, and back drafting from furnaces
and water heaters.
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Formaldehyde from durable press draperies and other
textiles, particle board products such as cabinets
and furniture framing, and adhesives.
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Radon, a radioactive gas from soil and rock beneath
and around the home's foundation, groundwater wells
and some building materials.
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Household products and furnishings such as paints,
solvents, air fresheners, hobby supplies,
dry-cleaned clothing, aerosol sprays, adhesives, and
fabric additives used in carpeting and furniture
which can release volatile organic compounds.
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Asbestos found in most homes more than 20 years old.
Sources include deteriorating, damaged or disturbed
pipe insulation, fire retardant, acoustical material
and floor tiles.
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Lead from lead-based paint dust created when
removing paint by sanding, scraping or burning.
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Particulates from dust and pollen, fireplaces, wood
stoves, kerosene heaters and un-vented gas space
heaters.
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Tobacco smoke, which produces particulates,
combustion products and formaldehyde.
Remedies to Indoor Air Quality Problems
Living Areas
Paneling, pressed-wood furniture and cabinetry. These
products may release formaldehyde gas.
Remedy:
Ask about formaldehyde content before buying furniture
or cabinets. Some types of pressed-wood products, such
as those with phenol resin, emit less formaldehyde.
Also, products coated with polyurethane or laminates may
reduce formaldehyde emissions. After installation, open
windows. Maintain moderate temperature and humidity.
Carpet.
Biological pollutants can grow on water-damaged carpet.
New carpet can release organic gases.
Remedy:
Promptly clean and dry water-damaged carpet, or remove
it altogether. If adhesives are needed, ask for
low-emitting ones. During installation, open doors and
windows, and use window fans or room air conditioners.
Vacuum regularly. Consider area rugs instead of
wall-to-wall carpet. Rugs are easier to remove and
clean, and the floor underneath also can be cleaned.
Floor tiles.
Some contain asbestos.
Remedy:
Periodically inspect for damage or deterioration. Do not
cut, rip, sand or remove any asbestos-containing
materials. If you plan to make changes that might
disturb the asbestos, or if materials are more than
slightly damaged, contact a professional for repair or
removal. Call your local or state health department or
the Environmental Protection Agency.
Moisture.
Moisture encourages biological pollutants, including
allergens such as mold, mildew, dust mites and
cockroaches.
Remedy: If possible, eliminate moisture sources.
Install and use exhaust fans. Use a dehumidifier if
necessary. Remove molds and mildew by cleaning with a
solution of chlorine bleach (1 cup bleach to 1 gallon
water). Maintain good fresh air with natural and
mechanical air circulation.
Fireplace. Your fireplace can be a source of
carbon monoxide and combustion pollutants.
Remedy:
Open the flue when using the fireplace. Have the flue
and chimney inspected annually for exhaust back
drafting, flue obstructions or cracks, excess creosote
or other damage. Install smoke and carbon monoxide
detectors.
Air conditioner.
This can be a source of biological allergens.
Remedy: If there is a water tray, empty and clean
it often. Follow all service and maintenance procedures,
including changing the filter.
Gas or kerosene space heater. These devices can
release carbon monoxide and combustion pollutants.
Remedy: Never use un-vented kerosene or gas space
heaters. In the room where the heater is located,
provide fresh air by opening a door to the rest of the
house, turning on an exhaust fan and slightly opening a
window.
Tobacco smoke. Smoke contains harmful combustion
and particulate pollutants, including carbon monoxide
and combustion byproducts.
Remedy: Do not smoke in your home or permit
others to do so, especially near children. If smoking
cannot be avoided indoors, open windows or use exhaust
fans.
Draperies. New draperies may be treated with a
formaldehyde-based finish and emit odors for a short
time.
Remedy: Before hanging, air draperies to
ventilate odors. After hanging, ventilate the area.
Maintain moderate temperature and humidity.
Lead-based paint. Paint manufactured before l978
may contain lead.
Remedy: Leave lead-based paint undisturbed if it
is in good condition. Before removing paint, test for
lead. Do-it-yourself lead test kits are available from
hardware or building supply stores. Do not sand, burn
off or remove lead-based paint yourself. Hire a person
with special training to correct lead-based paint
problems. For more information, call 1-800-LEAD-FYI.
Animals. Many animals leave allergens, such as
dander, hair, feathers or skin, in the air.
Remedy: Keep pets outdoors as often as possible.
Clean the entire house regularly. Deep clean areas where
pets are permitted. Clean pets regularly.
House dust mites. Biological allergens can
trigger asthma.
Remedy: Clean and vacuum regularly. Wash bedding
in hot water above 130 degrees F. Use more hard-surface
finishes; they are less likely to attract and hold dust
mites.
Kitchen
Household cleaners. Unhealthy or irritating
vapors may be released from chemicals in products.
Remedy: Select non-aerosol and nontoxic products.
Use, apply, store and dispose of them according to
manufacturers' directions. If products are concentrated,
label the storage container with dilution instructions.
Completely use up a product.
Pressed-wood cabinets. These can be a source of
formaldehyde vapor.
Remedy: Maintain moderate temperatures (80
degrees maximum) and humidity (about 45 percent). When
purchasing new cabinets, select solid wood or metal
cabinets or those made with phenol resin; they emit less
formaldehyde. Ventilate well after installation.
Un-vented gas stove and range. These are a source
of carbon monoxide and combustion byproducts.
Remedy: Keep appliance burners clean.
Periodically have burners adjusted (blue flame tip, not
yellow). Install and use an exhaust fan. Never use a gas
range or stove to heat your home.
Bathroom
Personal care products. Organic gases are
released from chemicals in some products, such as
deodorant and hair sprays, shampoos, toners, nail polish
and perfumes.
Remedy: Select odor-free or low odor-producing
products. Select non-aerosol varieties. Open a window,
or use an exhaust fan. Follow manufacturers' directions
when using the product and disposing of containers.
Air freshener. These products can release organic
gases.
Remedy: Open a window or use the exhaust fan
instead. If you use air fresheners, follow
manufacturers' directions. Select natural products.
Bedroom
Humidifier/vaporizer. Cold mist vaporizers can
encourage biological allergens, including mold, mildew
and cockroaches, that can trigger asthma and encourage
viruses and bacteria.
Remedy: Use and clean them according to
manufacturers' directions. Refill daily with fresh
water.
Moth repellents. These often contain the
pesticide paradichlorobenzene.
Remedy: Avoid breathing vapors. Place them in
tightly sealed trunks or other containers. Store
separately, away from living areas.
Dry-cleaned goods. Chemicals used in the cleaning
process release organic gases.
Remedy: Bring odors to the attention of your dry
cleaner. Try to air out dry-cleaned goods before
bringing them indoors. Seek alternatives to dry
cleaning, such as hand washing items.
Utility Room
Un-vented clothes dryer. Gas dryers produce
carbon monoxide and combustion byproducts and can be a
fire hazard.
Remedy: Regularly dispose of lint around and
under the dryer. Provide air for gas units. Vent the
dryer directly to the outside. Clean vent and ductwork
regularly.
Gas or oil furnace/boiler and gas water heater.
Air quality problems include back drafting of carbon
monoxide and combustion pollutants.
Remedy: Have your heating system and water
heater, including gas piping and venting, inspected
every year.
Asbestos pipe wrap and furnace insulation. These
can release asbestos fibers into the air.
Remedy: Periodically look for damage or deterioration.
Do not cut, rip, sand or remove any asbestos-containing
materials. If you plan to make changes that might
disturb the asbestos, or if materials are more than
slightly damaged, contact a professional for repair or
removal.
Basement
Ground moisture. Moisture encourages biological
allergens like mold and mildew.
Remedy: Inspect for condensation on walls,
standing water on the floor, or sewage leaks. To keep
basement dry, prevent outside water from entering by
installing roof gutters and downspouts, not watering
close to the foundation, grading soil away from the
home, and applying waterproofing sealants to basement
interior walls. For standing water, consider installing
a sump pump. If sewage is the source, have drains
professionally cleaned. If moisture has no obvious
source, install an exhaust fan controlled by humidity
levels. Remove mold and mildew. Regularly clean and
disinfect the basement floor drain.
Radon. This invisible, radioactive gas poses a
lung cancer risk.
Remedy: Test your home for radon. Do-it-yourself
kits are easy and inexpensive. Have an experienced radon
contractor fix your home if your radon level is 4
picocuries per liter (pCi/L) or higher. For more
information call 1-800-SOS-RADON.
Hobby products. Chemicals in products such as
solvents, paint, glue and epoxy release organic gases.
Remedy: Follow manufacturers' directions for use,
ventilation, application, clean-up, and container
storage and disposal. Use outdoors when possible.
Indoors, open a window, or use an exhaust fan. Reseal
containers well. Clean tools outside or in a
well-ventilated area.
Garage
Car and Small Engine Exhaust. These are sources
of carbon monoxide and combustion byproducts.
Remedy: Never leave vehicles, lawn mowers,
snowmobiles, etc., running in the garage.
Paint, solvent and cleaning supplies. These
products may release harmful vapors.
Remedy: Provide ventilation when using them.
Follow manufacturers' directions. Buy only as much as
you need. If the products contain methylene chloride,
such as paint strippers, use them outdoors. Reseal
containers well. Keep products in their original,
labeled containers. Clean brushes and other materials
outside.
Pesticides and fertilizers. Yard and Garden
chemicals may be toxic.
Remedy: Use non-chemical methods when possible.
Follow manufacturers' directions for mixing, applying,
storing and using protective clothing. Mix or dilute
them outdoors. Provide ventilation when using them
indoors. Store them outside of the home in their
original, labeled containers. After using the product,
remove your shoes and clean your hands and clothing to
avoid bringing the chemicals into your home.
Smoke and Carbon Monoxide Detectors
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Install a smoke detector in each bedroom or in the
adjacent hallway.
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If you have gas or other fossil fuel appliances in
the house, install carbon monoxide detectors in
these locations.
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Combination smoke and carbon monoxide detectors are
available.
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Check the batteries frequently.
If too little outdoor air enters a home, pollutants can
accumulate to levels that can pose health and comfort
problems. Unless they are built with special mechanical
means of ventilation, homes that are designed and
constructed to minimize the amount of outdoor air that
can "leak" into and out of the home may have higher
pollutant levels than other homes. However, because some
weather conditions can drastically reduce the amount of
outdoor air that enters a home, pollutants can build up
even in homes that are normally considered "leaky".
How Does Outdoor Air Enter a House?
Outdoor air enters and leaves a house by: infiltration,
natural ventilation, and mechanical ventilation. In a
process known as infiltration, outdoor air flows into
the house through openings, joints, and cracks in walls,
floors, and ceilings, and around windows and doors. In
natural ventilation, air moves through opened windows
and doors. Air movement associated with infiltration and
natural ventilation is caused by air temperature
differences between indoors and outdoors and by wind.
Finally, there are a number of mechanical ventilation
devices, from outdoor-vented fans that intermittently
remove air from a single room, such as bathrooms and
kitchen, to air handling systems that use fans and duct
work to continuously remove indoor air and distribute
filtered and conditioned outdoor air to strategic points
throughout the house. The rate at which outdoor air
replaces indoor air is described as the air exchange
rate. When there is little infiltration, natural
ventilation, or mechanical ventilation, the air exchange
rate is low and pollutant levels can increase.
Indoor Air Pollution and Health
Health effects from indoor air pollutants may be
experienced soon after exposure or, possibly, years
later.
Immediate effects
Immediate effects may show up after a single exposure or
repeated exposures. These include irritation of the
eyes, nose, and throat, headaches, dizziness, and
fatigue. Such immediate effects are usually short-term
and treatable. Sometimes the treatment is simply
eliminating the person's exposure to the source of the
pollution, if it can be identified. Symptoms of some
diseases, including asthma, hypersensitivity
pneumonitis, and humidifier fever, may also show up soon
after exposure to some indoor air pollutants.
The likelihood of immediate reactions to indoor air
pollutants depends on several factors. Age and
pre-existing medical conditions are two important
influences. In other cases, whether a person reacts to a
pollutant depends on individual sensitivity, which
varies tremendously from person to person. Some people
can become sensitized to biological pollutants after
repeated exposures, and it appears that some people can
become sensitized to chemical pollutants as well.
Certain immediate effects are similar to those from
colds or other viral diseases, so it is often difficult
to determine if the symptoms are a result of exposure to
indoor air pollution. For this reason, it is important
to pay attention to the time and place symptoms occur.
If the symptoms fade or go away when a person is away
from home, for example, an effort should be made to
identify indoor air sources that may be possible causes.
Some effects may be made worse by an inadequate supply
of outdoor air or from the heating, cooling, or humidity
conditions prevalent in the home.
Long-term effects
Other health effects may show up either years after
exposure has occurred or only after long or repeated
periods of exposure. These effects, which include some
respiratory diseases, heart disease, and cancer, can be
severely debilitating or fatal. It is prudent to try to
improve the indoor air quality in your home even if
symptoms are not noticeable.
While pollutants commonly found in indoor air are
responsible for many harmful effects, there is
considerable uncertainty about what concentrations or
periods of exposure are necessary to produce specific
health problems. People also react very differently to
exposure to indoor air pollutants. Further research is
needed to better understand which health effects occur
after exposure to the average pollutant concentrations
found in homes and which occurs from the higher
concentrations that occur for short periods of time.