Air Quality in the Home
Quick Facts...
- Indoor air quality can be worse than that
of outdoor air.
- Problems can arise from moisture, insects,
pets, appliances, radon, materials used in household products and
furnishings, smoke and other sources.
- Effects range from minor annoyances to
major health risks.
- 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:
- Unusual and noticeable odors.
- Stale or stuffy air.
- Noticeable lack of air movement.
- Dirty or faulty central heating or air
conditioning equipment.
- Damaged flue pipes or chimneys.
- Unvented combustion air sources for fossil
fuel appliances.
- Excessive humidity.
- Presence of molds and mildew.
- Health reaction after remodeling,
weatherizing, using new furniture, using household and hobby products,
or moving into a new home.
- 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:
- 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.
- Combustion products, including carbon
monoxide, from unvented fossil fuel space heaters, unvented gas stoves
and ovens, and backdrafting from furnaces and water heaters.
- Formaldehyde from durable press draperies
and other textiles, particle board products such as cabinets and
furniture framing, and adhesives.
- Radon, a radioactive gas from soil and
rock beneath and around the home's foundation, groundwater wells and
some building materials.
- 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.
- 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.
- Lead from lead-based paint dust created
when removing paint by sanding, scraping or burning.
- Particulates from dust and pollen,
fireplaces, wood stoves, kerosene heaters and unvented gas space
heaters.
- 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 backdrafting, 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 unvented 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 nonaerosol 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.
Unvented 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 nonaerosol 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
Unvented 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 backdrafting 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 nonchemical 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
- Install a smoke detector in each bedroom
or in the adjacent hallway.
- If you have gas or other fossil fuel
appliances in the house, install carbon monoxide detectors in these
locations.
- Combination smoke and carbon monoxide
detectors are available.
- Check the batteries frequently.
Amount of Ventilation
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.