HAVE TO BE A PROBLEM
There are reliable ways to measure indoor radon for short-term test periods that last only a few days, and for long-term test periods that may range from a few months to more than a year. Using recommended measurement devices, you can determine the radon potential of the home under "worst case conditions" (short term test) or measure actual radon exposure under normal living conditions (long term test).
Short-Term Test Devices
Often, at the time of resale, it is desirable to know what the potential radon exposures could be, independent of how the occupants use a building. Short-term tests typically are conducted over a two to seven day period. Results of short term tests represent the radon potential of the home, more than the actual average exposure to residents under normal living conditions, unless the residents keep the home's windows and doors closed year-round.
There are two types of short-term test devices:
It is not appropriate to use "Grab Samples," which test for less than 48 hours, as this is more of a diagnostic device and will not provide a representative radon potential measurement for the home.
If a short-term radon test is conducted correctly for a minimum of two days, under closed-house conditions, one can reasonably say:
For the occupants of a home, actual radon exposure depends on how they use the home, where in the home the occupants spend their time, and how much fresh air is brought into the living area. Since these factors may vary over time, the only reliable way of measuring the actual radon exposure is to conduct a long-term test for a minimum of 91 days under normal living conditions.
In the past, prospective homeowners have often been reluctant to purchase a home before performing a long-term test for fear of not being able to correct a radon problem afterward. However, improved technology and the proven durability of radon mitigation systems have served to reduce much of that concern.
This does not mean that a short-term test is less valuable as part of a home inspection process, but rather, if the results of that test show a potential radon concern, a long-term test can more accurately show average radon levels. By conducting a long-term test after moving into a home, the homeowner can control test conditions and, if needed, make decisions on how the mitigation system will be installed.
The placement of the test device within the home must be in accordance with the manufacturer's instructions.
Radon decay products can also be measured using a special monitor that reports in Working Levels (WL). This can be done as an initial measurement or, more typically, after initial measurements have identified a potential concern in commercial buildings or homes with relatively low initial radon readings. The EPA guidance for radon decay products (comparable to 4.0 pCi/L of radon) recommends that people should avoid long-term exposures in excess of 0.02 WL of radon decay products.
Homebuyers and sellers often prefer to have a radon test performed by a trained professional tester. In that case, EPA strongly recommends the use of a qualified radon measurement professional who has been trained in the proper placement of radon measurement devices and the interpretation of their results.
Here are some tips for testing and reducing radon:
The Arizona Radiation Regulatory Agency (ARRA) does not regulate or certify radon testers or mitigation specialists.
Contractors are licensed and regulated in Arizona by the Arizona Registrar of Contractors (ROC). Radon testers or mitigation specialists may need to be licensed by the ROC. You can contact the ROC as follows:
Information is also available at the ROC website:
To find qualified radon
contractors, EPA recommends that you contact one or both of the two privately-run national certification programs listed below. You can find a listing
of certified individuals through their websites as follows:
In addition to asking about a radon contractor's training and credentials, homeowners should always: