Appropriate Radon Testing Methods:
Direct measurements in a building of the gamma radiation or radon emanation from a material, such as granite, is not a reliable indicator of radon concentrations that will be in the air you breathe. Attempts to use such measurements for estimating risk are subject to large errors due to the:
- wide variability of radon emanation rates across the surface of granite.
- significant variability in ventilation rates from home to home and room to room.
- volume of space that the building material is contained in.
- Diagnostic measurements of the radon in the air you breathe can provide better risk estimates.
- Perform a radon measurement according to testing protocols (specified by EPA or AARST as noted below) in the lowest level (or lived-in level) of your home.
- At the same time, perform another test in the room where the granite countertop or other suspect building material exists. You may also want to test in a highly occupied room, like your bedroom. (Use different rooms if these locations are on the same floor.)
- Place the test devices at least 20 inches off the floor according to testing protocols and at least 20 inches away from the countertop or suspect material. Carefully follow all manufacturers’ test kit instructions.
- You may also contact a State licensed or nationally certified radon measurement professional to conduct the measurements for you.
- If any of the test results are at or above the EPA recommended action levels retest these areas to confirm the initial results.
Interpreting Radon Test Results:
For guidance on test results and protocols for measurements of radon in the air, see documents such as EPA’s Citizens Guide to Radon or other EPA publications at http://www.epa.gov/radon/pubs. Other information and publications for measuring radon in the air for home and multi-family dwellings can also be found at http://www.aarst.org/.
The best approach to reduce radon in the home is to install an active soil depressurization system (ASD) and reduce the entry of radon coming from the soil. In some cases, increasing the entry of outdoor air to the home is an appropriate method to reduce radon levels by dilution and improve indoor air quality. Both of these methods require a qualified radon mitigation professional to design and install the appropriate radon reduction system. Only in extreme cases would removal of the granite be necessary to reduce the radon concentration, assuming appropriate measurements confirm it as the significant source.
Testing the air you breathe is the best method to determine your risk from radon, whether the source of the radon is from the soil or from a material inside the building.