Moisture
and Indoor Air Quality
The indoor air pollution problem
Modern, almost air-tight buildings with low fresh
air exchange do not provide sufficient ventilation
to remove indoor air contaminants. This increases
the pollutants in indoor air and causes the "Sick Building Syndrome." Boosting outside airflow would improve the indoor air
quality, but it would be very costly in energy losses
in heated or air-conditioned air.
People spend on average 93 percent of their time indoors,
which makes indoor air quality important to their
health. But the indoor air pollution problem is most
critical in homes, where people spend most of their
time (on average 70%, more for children).
Indoor air is often more polluted than the outdoor
air
in our most polluted cities. Openings in foundations
and pores in concrete draw in moisture, which causes
mildew, molds, excessive spores, mites, and pathogens.
Ventilation and natural air movement then spread the
biological and other pollutants throughout the building.
Biological pollutants in indoor air
The
most common indoor biological contaminants are molds,
mildew, bacteria, viruses, house dust mites, animal
dander, cat saliva, and pollen.
The
particles are too small to be visible and travel suspended
in air.
The necessary pre-condition for biological growth
is moisture. Suitable conditions can be found in bathrooms,
damp or leaking basements, humidifiers and air conditioners,
carpets and upholstered furniture. Reducing moisture
lowers the biological contaminants in indoor air.
"Dust mites, molds, animal dander, and other
biologicals are found in some degree in every home
and workplace. High relative humidity is the primary factor encouraging biological
agents to grow and be released into the air."
(EPA)
Water seepage and infiltration of soil gas
Pores in concrete naturally draw in water from the
surrounding soil by capillary action, just like a
wick. The moisture usually evaporates as invisible
dampness, while it releases dissolved contaminants,
such as minerals and radon. The average basement absorbs
18 gallons of water each day.
Soil gas, rich in moisture, pesticide, radon and biological
decomposition gases, collects in the gravel and disturbed
soil around foundations, and is drawn into homes by
the lower air pressure indoors through openings and
pores in concrete. Based on tests, air infiltration
into US homes ranges 0.2-2.2 air changes per hour;
modern homes are designed for 0.3 - 0.5 air changes.
Some of this air comes from the ground. The infiltration
of soil gas, rich in moisture and often radon, ranges
from 1% to 20% of the total air infiltration into
a home.
The health effects of biological contaminants
Indoor biological pollutants are a major contributing
factor to asthma and allergies, which have become
a growing public health problem, particularly among
children.
EPA warns: "Biological agents are known to cause
three types of human diseases:
- infections, where pathogens invade human tissues;
- hypersensitivity diseases, where specific activation of
the immune system causes disease; and
- toxicoses, where biologically produced chemical toxins
cause direct toxic effects".
Many health effects are associated with biological
contaminants:
- Some molds and mildews can release disease-causing toxins.
These toxins can damage a variety of organs and
tissues in the body, including the liver, central
nervous system, digestive tract, and immune system.
- 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.
(Environmental Health Center of The National Safety
Council)
Pathogens in indoor air
In
the outdoor air, microbes usually die off due to sunlight,
temperature extremes, dehydration, and oxygen, although
spores and some environmental bacteria are naturally
more resistant. But the moist and controlled indoor
climate favors the survival and transmission of contagious
human pathogens, as well as some outdoor fungi and
bacteria.
Airborne particles or large molecules that contain
living organisms or were released from living organisms
are called bioaerosols. The size of bioaerosol particles
varies from 100 microns (thousandths of a millimeter)
to 0.01 micron:
|
|
Pollen
|
100
|
microns
|
|
Spore
|
10
|
"
|
|
Bacteria
|
1
|
"
|
|
Virus
|
0.1
|
"
|
The diameter of human hair is 80-100 microns. Particles
smaller than 0.5 microns do not settle by gravity
but remain perpetually suspended in the indoor air
people inhale.
(Aerobiological Engineering)
How to reduce biological contaminants in your home
Take steps to minimize indoor biological pollutants
by eliminating water seepage and reducing dampness
in your foundation slab. Seal the concrete. install
the injector2 and mold shield your home by a Healthy
Builder.
Pesticide moisture flow upwards through the concrete
slabs by vapor diffusion and capillary transmission
passes through the top surface of the concrete slabs
as well as through floor surface treatments (carpet,
tile, wood floors) and leads to un-healthy contamination
problems.
.
Today's almost airtight buildings let in little fresh
air and draw from the ground more "soil gas",
rich in moisture and vapors from pesticides below
ground. Pores in concrete draw in water by capillary
action. The average (slab) lets in over (10)
gallons of water each day, several times more than
showering and cooking combined!
Make sure your Builder installs the Injector2®, the world's only healthier way to control termites
that come into the home or building from
below the foundation.
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