Pollutants in Your Home
information will provide you with answers to the
- What indoor
biological pollution is
- Whether your
home or lifestyle promotes its development
- How to
control its growth and buildup.
pollution in cities is a major health problem. Much
effort and money continues to be spent cleaning up
pollution in the outdoor air. But air pollution can be
a problem where you least expect it, in the place you
may have thought was safest -- your home. Many
ordinary activities such as cooking, heating, cooling,
cleaning, and redecorating can cause the release and
spread of indoor pollutants at home. Studies have
shown that the air in our homes can be even more
polluted than outdoor air.
spend up to 90 percent of their time indoors, often at
home. Therefore, breathing clean indoor air can have
an important impact on health. People who are inside a
great deal may be at greater risk of developing health
problems, or having problems made worse by indoor air
pollutants. These people include infants, young
children the elderly and those with chronic illnesses.
pollutants are or were living organisms. They promote
poor indoor air quality and may be a major cause of
days lost from work or school, and of doctor and
hospital visits. Some can even damage surfaces inside
and outside your house. Biological pollutants can
travel through the air and are often invisible.
common indoor biological pollutants are:
Dander (minute scales from hair, feathers,
Mite and Cockroach parts
agents (bacteria or viruses)
Some of these
substances are in every home. It is impossible to get
rid of them all. Even a spotless home may permit the
growth of biological pollutants. Two conditions are
essential to support biological growth nutrients and
moisture. These conditions can be found in many
locations, such as bathrooms, damp or flooded
basements, wet appliances (such as humidifiers or air
conditioners), and even some carpets and furniture.
materials and construction techniques may reduce the
amount of outside air brought into buildings which may
result in high moisture levels inside. Using
humidifiers, unvented heaters, and air conditioners in
our homes has increased the chances of moisture
forming on interior surfaces. This encourages the
growth of certain biological pollutants.
The Scope Of
information about sources and health effects of
biological pollutants is based on studies of large
office buildings and two surveys of homes in northern
U.S. and Canada. These surveys show that 30% to 50% of
all structures have damp conditions which may
encourage the growth and buildup of biological
pollutants. This percentage is likely to be higher in
warm, moist climates.
or illnesses have been linked with biological
pollutants in the indoor environment. However, many of
them also have causes unrelated to the indoor
environment. Therefore, we do nut know how many health
problems relate only to poor indoor air.
Effects Of Biological Pollutants
All of us are
exposed to biological pollutants. However, the effects
on our health depend upon the type and amount of
biological pollution and the individual person. Some
people do not experience health reactions from certain
biological pollutants, while others may experience one
or more of the following reactions:
Except for the
spread of infections indoors, ALLERGIC REACTIONS may
be the most common health problem with indoor air
quality in homes. They are often connected with animal
dander (mostly from cats and dogs), with house dust
mites (microscopic animals living in household dust),
and with pollen. Allergic reactions can range from
mildly uncomfortable to life-threatening, as in a
severe asthma attack. Some common signs and symptoms
nose and sneezing
and difficulty breathing
are especially concerned about people with asthma
These people have very sensitive airways that can
react to various irritants, making breathing
difficult. The number of people who have asthma has
greatly increased in recent years. The number of
people with asthma has gone up by 59 percent since
1970, to a total of 9.6 million people. Asthma in
children under 15 years of age has increased 41
percent in the same period, to a total of 2.6 million
children. The number of deaths from asthma is up by 68
percent since 1979, to a total of almost 4,400 deaths
concerned about the effects on your health that may be
related to biological pollutants in your home? Before
you discuss your concerns with your doctor, you should
know the answers to the following questions. This
information can help the doctor determine whether your
health problems may be related to biological
- Does anyone
in the family have frequent headaches, fevers,
itchy watery eyes, a stuffy nose, dry throat, or a
cough? Does anyone complain of feeling tired or
dizzy all the time? Is anyone wheezing or having
difficulties breathing on a regular basis?
- Did these
symptoms appear after you moved to a new or
- Do the
symptoms disappear when you go to school or the
office or go away on a trip, and return when you
- Have you
recently remodeled your home or done any energy
conservation work, such as installing insulation,
storm windows, or weather stripping? Did your
symptoms occur during or after these activities?
- Does your
home feel humid? Can you see moisture on the
windows or on other surfaces, such as walls and
- What is the
usual temperature in your home? Is it very hot or
- Have you
recently had water damage?
- Is your
basement wet or damp?
- Is there any
obvious mold or mildew?
- Does any
part of your home have a musty or moldy odor?
- Is the air
- Do you have
- Do your
house plants show signs of mold?
- Do you have
air conditioners or humidifiers that have not been
- Does your
home have cockroaches or rodents?
DISEASES caused by bacteria and viruses,
such as flu, measles, chicken pox, and tuberculosis,
may be spread indoors. Most infectious diseases pass
from person to person through physical contact.
Crowded conditions with poor air circulation can
promote this spread. Some bacteria and viruses thrive
in buildings and circulate through indoor ventilation
systems. For example, the bacterium causing
Legionnaire's disease, a serious and sometimes lethal
infection, and Pontiac Fever, a flu-like illness, have
circulated in some large buildings.
REACTIONS are the least studied and
understood health problem caused by some biological
air pollutants in the home. Toxins can damage a
variety of organs and tissues in the body, including
the liver, the central nervous system, the digestive
tract, and the immune system.
There is no
simple and cheap way to sample the air in your home to
determine the level of all biological pollutants.
Experts suggest that sampling for biological
pollutants is not a useful problem-solving tool. Even
if you had your home tested, it is almost impossible
to know which biological pollutant(s) cause various
symptoms or health problems. The amount of most
biological substances required to cause disease is
unknown and varies from one person to the next.
Does this make
the problem sound hopeless? On the contrary, you can
take several simple, practical actions to help remove
sources of biological pollutants, to help get rid of
pollutants, and to prevent their return.
A Walk Through Your Home
touring your household. Follow your nose, and use your
eyes. Two major factors help create conditions for
biological pollutants to grow nutrients and constant
moisture with poor air circulation.
- Dust and
construction materials, such as wood, wallboard,
and insulation, contain nutrients that allow
biological pollutants to grow. Firewood also is a
source of moisture, fungi, and bugs.
such as humidifiers, kerosene and gas heaters, and
gas stoves add moisture to the air.
- A musty
odor, moisture on hard surfaces, or even water
stains, may be caused by:
Basements, attics, and crawlspaces
Heating and air-conditioning ducts
Humidifiers and dehumidifiers
Refrigerator drip pans
What You Can
Do About Biological Pollutants
Before you give
away the family pet or move, there are less drastic
steps that can be taken to reduce potential problems.
Properly cleaning and maintaining your home can help
reduce the problem and may avoid interrupting your
normal routine. People who have health problems such
as asthma, or are allergic, may need to do this and
more. Discuss this with your doctor.
Water in your
home can come from many sources. Water can enter your
home by leaking or by seeping through basement floors.
Showers or even cooking can add moisture to the air in
your home. The amount of moisture that the air in your
home can hold depends on the temperature of the air.
As the temperature goes down, the air is able to hold
less moisture. This is why, in cold weather, moisture
condenses on cold surfaces (for example, drops of
water form on the inside of a window). This moisture
can encourage biological pollutants to grow.
many ways to control moisture in your home:
- Fix leaks
and seepage. If water is entering the house from
the outside, your options range from simple
landscaping to extensive excavation and
waterproofing. (The ground should slope away from
the house). Water in the basement can result from
the lack of gutters or a water flow toward the
house. Water leaks in pipes or around tubs and
sinks can provide a place for biological
pollutants to grow.
- Put a
plastic cover over dirt crawlspaces to prevent
moisture from coming in from the ground. Be sure
crawlspaces are well-ventilated.
- Use exhaust
fans in bathrooms and kitchens to remove moisture
to the outside (not into the attic) Vent your
clothes dryer to the outside.
- Tarn off
certain appliances (such as humidifiers or
kerosene heaters) if you notice moisture on
windows and other surfaces.
dehumidifiers and air conditioners, especially in
hot, humid climates, to reduce moisture in the
air, but be sure that the appliances themselves
don't become sources of biological pollutants.
- Raise the
temperature of cold surfaces where moisture
condenses. Use insulation or storm windows. (A
storm window installed on the inside works better
than one installed on the outside ) Open doors
between rooms (especially doors to closets which
may be colder than the rooms) to increase
circulation. Circulation carries heat to the cold
surfaces Increase air circulation by using fans
and by moving furniture from wall corners to
promote air and heat circulation. Be sure that
your house has a source of fresh air and can expel
excessive moisture from the home.
- Pay special
attention to carpet on concrete floors. Carpet can
absorb moisture and serve as a place for
biological pollutants to grow. Use area rugs which
can be taken up and washed often In certain
climates, if carpet is to be installed over a
concrete floor, it maybe necessary to use a vapor
barrier (plastic sheeting) over the concrete and
cover that with sub-flooring (insulation covered
with plywood) to prevent a moisture problem.
problems and their solutions differ from one
climate to another. The Northeast is cold and wet,
the Southwest is hot and dry, the South is hot and
wet, and the Western Mountain states are cold and
dry. All of these regions can have moisture
problems. For example, evaporative coolers used in
the Southwest can encourage the growth of
biological pollutants. In other hot regions, the
use of air conditioners which cool the air too
quickly may prevent the air conditioners from
running long enough to remove excess moisture from
the air. The types of construction and
weatherization for the different climates can lead
to different problems and solutions.
Biological Pollutants May Be Found in the Home
- Dirty air
humidifiers and/or dehumidifiers
without vents or windows
without vents or windows
refrigerator drip pans
room with unvented dryer
- Carpet on
damp basement floor
- Closet on
heating/air conditioning system
- Dogs or
damage (around windows, the roof or the
And Clean All Appliances That Come In Contact With
- Have major
appliances, such as furnaces, heat pumps and
central air conditioners, inspected and cleaned
regularly by a professional, especially before
seasonal use. Change filters on heating and
cooling systems according to manufacturer's
directions. (In general, change filters monthly
during use.) When first turning on the heating or
air conditioning at the start of the season,
consider leaving your home until it airs out.
- Have window
or wall air-conditioning units cleaned and
serviced regularly by a professional, especially
before the cooling season. Air conditioners can
help reduce the entry of allergy-causing pollen.
But they may also become a source of biological
pollutants if not properly maintained. Clean the
coils and rinse the drain pans according to
manufacturer's instructions, so water can-not
collect in pools.
furnace-attached humidifiers cleaned and serviced
regularly by a professional, especially before the
manufacturer's instructions when using any type of
humidifier Experts differ on the benefits of using
humidifiers. If you do use a portable humidifier
(approximately 1 to 2 gallon tanks), be sure to
empty its tank every day and refill with distilled
or demineralized water, or even fresh tap water if
the other types of water are unavailable For
larger portable humidifiers, change the water as
recommended by the manufacturer. Unplug the
appliance before cleaning. Every third day, clean
all surfaces coming in contact with water with a
3% solution of hydrogen peroxide, using a brush to
loosen deposits Some manufacturers recommend using
diluted household bleach for cleaning and
maintenance, generally in a solution of one-half
cup bleach to one gallon water When any household
chemical, rinse well to remove all traces of
chemical before refilling humidifier.
dehumidifiers daily and clean often. If possible,
have the appliance drip directly into a drain.
Follow manufacturer's instructions for cleaning
and maintenance. Always disconnect the appliance
refrigerator drip pans regularly according to
manufacturer's instructions. If refrigerator and
freezer doors don't seal properly, moisture may
build up and mold can grow. Remove any mold on
door gaskets and replace faulty gaskets.
- Clean moist
surfaces, such as showers and kitchen counters.
- Remove mold
from walls, ceilings, floors, and paneling. Do not
simply cover mold with paint, stain, varnish, or a
moisture-proof sealer, as it may resurface.
moldy shower curtains, or remove them and scrub
well with a household cleaner and rinse before
dust is very important for people who are allergic to
animal dander and mites. You cannot see mites, but you
can either remove their favorite breeding grounds or
keep these areas dry and clean. Dust mites can thrive
in sofas, stuffed chairs, carpets, and bedding. Open
shelves, fabric wallpaper, knickknacks, and venetian
blinds are also sources of dust mites. Dust mites live
deep in the carpet and are not removed by vacuuming.
Many doctors suggest that their mite-allergic patients
use washable area rugs rather than wall-to-wall
- Always wash
bedding in hot water (at least 1300 F) to kill
dust mites. Cold water won't do the job. Launder
bedding at least every 7 to 10 days.
synthetic or foam rubber mattress pads and
pillows, and plastic mattress covers if you are
allergic Do not use fuzzy wool blankets, feather
or wool-stuffed comforters, and feather pillows.
- Clean rooms
and closets well, dust and vacuum often to remove
surface dust. Vacuuming and other cleaning may not
remove all animal dander, dust mite material, and
other biological pollutants. Some particles are so
small they can pass through vacuum bags and remain
in the air If you are allergic to dust, wear a
mask when vacuuming or dusting. People who are
highly allergy-prone should not perform these
tasks. They may even need to leave the house when
someone else is cleaning.
yourself by inspecting your potential new home. If you
identify problems, have the landlord or seller correct
them before you move in, or even consider moving
professionals check the heating and cooling
system, including humidifiers and vents Have duct
lining and insulation checked for growth.
- Check for
exhaust fans in bathrooms and kitchens If there
are no vents, do the kitchen and bathrooms have at
least one window a piece? Does the cook top have a
hood vented outside? Does the clothes dryer vent
outside? Are all vents to the outside of the
building, not in attics or crawlspaces?
Look for obvious mold growth throughout the house,
including attics, basements, and crawlspaces and
around the foundation. See if there are many
plants close to the house, particularly if they
are damp and rotting. They are a potential source
of biological pollutants. Downspouts from roof
gutters should route water away from the building.
- Look for
stains on the walls, floor or carpet (including
any carpet over concrete floors) as evidence of
previous flooding or moisture problems. Is there
moisture on windows and surfaces? Are there signs
of leaks or seepage in the basement?
- Look for
rotted building materials which may suggest
moisture or water damage.
- If you or
anyone else in the family has a pet allergy, ask
if any pets have lived in the home.
- Examine the
design of the building. Remember that in cold
climates, overhanging areas, rooms over unheated
garages, and closets on outside walls may be prone
to problems with biological pollutants.
- Look for
signs of cockroaches.
read instructions for use and any cautionary labeling
on cleaning products before beginning cleaning
- Do not mix
any chemical products. Especially, never mix
cleaners containing bleach with any product (such
as ammonia) which does not have instructions for
such mixing When chemicals are combined, a
dangerous gas can sometimes be formed.
chemicals may cause burning or irritation to skin
chemicals may be harmful if swallowed, or inhaled.
contact with skin, eyes, mucous membranes and
breathing vapor. Open all windows and doors and
use an exhaust fan that sends the air outside.
household chemicals out of reach of children.
treated surface areas well to remove all traces of
damage is already done?
Follow these guidelines for correcting water
- Throw out
mattresses, wicker furniture, straw baskets and
the like that have been water damaged or contain
mold. These cannot be recovered.
- Discard any
water-damaged furnishings such as carpets, drapes,
stuffed toys, upholstered furniture and ceiling
tales, unless they can be recovered by steam
cleaning or hot water washing and thorough drying.
- Remove and
replace wet insulation to prevent conditions where
biological pollutants can grow.
Lung Association for copies of: Indoor Air
Pollution Fact Sheets, Air Pollution in Your Home and
other publications on indoor air pollution.
Contact the U.S.
Consumer Product Safety Commission for copies
of The Inside Story: A Guide to Indoor Air Quality and
Humidifier Safety Alert. The U.S. Consumer Product
Safety Commission protects the public from the
unreasonable risk of injury or death from 15,000 types
of consumer products under the agency's jurisdiction.
To report a dangerous product or a product-related
injury, you can go to CPSC's forms page and use the
first on-line form on that page. Or, you can call
CPSC's hotline at (800) 638-2772 or CPSC's
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Pollutants in Your Home
Lung Association and the U.S. Consumer Product
Safety Commission CPSC