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To better understand radon gas it
is important to understand its ultimate
source, uranium. Some level of uranium
is found in most rocks. As uranium
decays, it produces radium. As radium
decays, it produces radon gas. So
the earth and rock below your home
is the primary source of radon.
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Scientific studies have shown that
radon gas is a known carcinogen. You
can’t see radon, you can’t
smell it, you can’t taste it,
and you can’t even keep it out
of your home without installing a
mitigation system, but prolonged exposure
at high levels can cause lung cancer.
Specifically, the Surgeon General
identified radon gas as the second
leading cause of lung cancer.
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The EPA recommends that if you are
buying a home or selling your home
you have it tested for radon. If radon
test results are 4.0 picocuries per
liter (pCi/L) or higher, the EPA recommends
mitigation.
Based on a national residential survey
completed in 1991, the average indoor
radon level is 1.3 pCi/L in the United
States and 6.7% of homes would test
over 4.0 pCi/L. The Indoor Air Division
of Environmental Solutions Inc., sates
the average radon level in a St. Louis
home is 3.1 pCi/L and 20% of homes
would test over 4.0 pCi/L.
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Radon levels tend to vary from day
to day, season to season, and even
hour to hour. Therefore, a long-term
test (90 days or greater) produces
a more reliable indication of annual
averages. However, due to the aggressive
timelines of a real estate transaction
the EPA has defined protocols and
approved equipment for performing
a short-term test.
- Time Integrated Sampling
– (i.e. charcoal canisters,
alpha track detectors) Provides
only the average concentration
over a period of time.
- Continuous Sampling
– (i.e. continuous electronic
monitors) Provides the average
concentration over a period of
time AND hourly interval readings.
Additionally, sophisticated electronics
may also include the ability to
monitor barometric pressure, temperature,
humidity levels, and tamper detection
features.
It is the responsibility of the
Certified Radon Tester to clearly
communicate the protocol or conditions
that must be met while the test
is performed. The condition that
is most likely to impact the seller
or owner of the home is that the
home must maintain “closed
house conditions” prior to
and during the test. Closed house
conditions means that all windows
and doors should remain closed while
the furnace and/or air conditioning
systems operate under normal conditions.
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The most common and widely accepted
form of mitigation is a system.
These systems do not require major
changes to your home and utilize
vent pipe(s) and fan(s) to reduce
radon. Radon gas is prevented from
entering the home from below the
concrete floor and from outside
the foundation by reducing the pressure
in the soil surrounding the foundation.
Thus, the flow of air is from the
basement outward rather than from
the surrounding ground inward.
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For additional information regarding
radon gas the following EPA web
site may prove beneficial:
http://www.epa.gov/radon/pubs/consguid.html
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