RE: Radon Testing

[MARK WINSLOW <WINSLOW.MARK@epamail.epa.gov>]

RE: Radon Testing

Unfortunately a simple grab Rn sample will not give you an accurate
measurement.  EPA's recommended level of 4 pCi/l is an AVERAGE
measurement.  The Rn levels in homes will change significantly during the
day for several reasons.  

Examples which will cause changes are the follow:  Doing laundry or
showering will drive Rn from water into the air, heating or cooling your home
will create a chimney effect which sucks Rn from the ground, rain will create
a blanket effect with your home acting like a vent for the surrounding soil,
finally high wind outside can even create a pressure differential which
changes Rn levels. 

A simple grab sample can show you what Rn levels are like at that moment
in time.  However, it will NOT give you an accurate measurement of the
average Rn level of your home.

The basic EPA protocol is to conduct a simple 1 week measurement with a
carbon canister.  If that reads somewhat high you should take a long term
(several months) measurement with an alpha track detector.  After that point
you might spend money to fix your home.


Mark Winslow
US EPA - Region 2
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