Biological
Contaminants
Biological
contaminants are or were living organisms. They can cause poor indoor
air quality and some can damage surfaces inside and outside the
home. These contaminants can travel through the air and are often
invisible. Common indoor biological contaminants include bacteria,
molds, mildew, viruses, animal dander and cat saliva, house dust
mites, cockroaches, and pollen. There are many sources of the pollutants:
People,
animals, soil, and plant debris carry bacteria.
People and animals transmit viruses.
Pollens originate from plants.
The protein in urine from rats and mice is a potent allergen. When
it dries, it can become airborne.
The
two conditions that are necessary to support biological growth are
nutrients and moisture. These conditions can be found in many locations,
such as bathrooms, damp or flooded basements, wet appliances (humidifiers
and air conditioners), and some carpets and furniture. Mold, mildew,
and other biological contaminants can grow in contaminated central
air handling system. These systems can distribute the contaminants
through the home.
What
Are The Health Effect?
Many
health effects are associated with biological contaminants:
Some
may trigger allergic reactions, including hypersensitivity pneumonitis,
Allergic rhinitis, and some types of asthma. Allergic reactions
occur only after repeated exposure to a specific biological allergen.
However, that reaction may occur immediately upon reexposure or
after multiple exposures over time. As a result, people who have
noticed only mild allergic reactions, or none at all, may suddenly
find themselves very sensitive to particular allergens.
Infectious
diseases, such as influenza, measles, tuberculosis, and chicken
pox,
Are transmitted through the air.
Some
molds and mildews can release disease-causing toxins. These toxins
Damage a variety of organs and tissues in the body, including the
liver, central nervous system, digestive tract, and immune system.
Some diseases, like humidifier fever, can be traced to microorganisms
that grow in home heating and cooling systems, although it is not
certain whether the disease is an allergic reaction or a toxic response.
Symptoms
of exposure to biological contaminants include sneezing, watery
Eyes, coughing, shortness of breath, dizziness, lethargy, fever,
and digestive problems. Children, elderly people, and people with
breathing problems, allergies, and lung diseases are particularly
susceptible to disease-causing biological agents in the indoor air.
How
Can I Reduce Exposure?
You
can reduce your exposure to biological contaminants in several ways:
Install
and use exhaust fans that are vented to the outdoors in kitchens
and bathrooms. Vent clothes dryer air to the outdoors.
Keep the relative humidity level of the house between 30 to 50 percent.
Dry
off wet surfaces and correct water problems.
Thoroughly
clean and dry water-damaged carpets and building materials
(within 24 hours if possible).
Dust
mites, pollens, animal dander, and other allergy-causing agents
can be
reduced, although not eliminated, through regular cleaning.
Ventilate
the attic and crawl spaces to prevent moisture buildup.
- Take
steps to minimize biological pollutants in basements. Regularly
clean
and disinfect any basement floor drain. If needed, use a dehumidier
to keep
relative humidity between 30 to 50 percent.
Maintain
and clean all appliances that come in contact with water. Have a
professional inspect and clean appliances, such as furnaces, heat
pumps,
central and wall air-conditioning units, and furnace-attached humidifiers.
Change the filters on heating and cooling systems frequently according
to the
manufacturer's directions.
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