Homeowners can measure radon
concentrations in their homes themselves using passive
radon detectors of the AC and AT types described below.
The AC type is a short-term screening device. The AT
type is a long-term measurement device providing better
accuracy. The AT type must be used for a minimum of 30
days but are typically used for 3 to 12 months. The 12
month measurement provides an annual average
concentration that residents are exposed to.
If testing is done in conjunction
with a real estate transaction, it is advisable that a
neutral third party conduct the testing utilizing EPA
testing protocols. It is not advised that the seller,
buyer or real estate professional conduct the testing.
It is recommended that the radon measurement service
provider utilized be listed as certified by the National
Environmental Health Association (NEHA) or the National
Radon Safety Board (NRSB).
AC - Activated
Charcoal Adsorption
For this method, an airtight
container with activated charcoal is opened in the area
to be sampled and radon in the air adsorbs onto the
charcoal granules. At the end of the sampling period,
the container is sealed and may be sent to a laboratory
for analysis.
The gamma decay from the radon
adsorbed to the charcoal is counted on a scintillation
detector and a calculation based on calibration
information is used to calculate the radon concentration
at the sample site. Charcoal adsorption detectors,
depending on design, are deployed from two to seven
days. Because charcoal allows continual adsorption and
desorption of radon, the method does not give a true
integrated measurement over the exposure time. Use of a
diffusion barrier over the charcoal reduces the effects
of drafts and high humidity.
AT - Alpha Track
Detection (filtered)
For this method, the detector is a
small piece of special plastic or film inside a small
container. Air being tested diffuses through a filter
covering a hole in the container. When alpha particles
from radon and its decay products strike the detector,
they cause damage tracks. At the end of the test the
container is sealed and returned to a laboratory for
reading.
The plastic or
film detector is treated to enhance the damage tracks
and then the tracks over a predetermined area are
counted using a microscope or optical reader. The number
of tracks per area counted is used to calculate the
radon concentration of the site tested. Exposure of
alpha track detectors is usually 3 to 12 months, but
because they are true integrating devices, alpha track
detectors may be exposed for shorter lengths of time
when they are measuring higher radon concentrations.
Following are links to
companies providing test kits and a link to the National
Safety Council for discounted test kits:
The following are links to the
national certification programs for radon measurement
professionals that can provide radon measurement
services in Nevada:
