XI. What Will Your Results Mean

Radon is measured in picocuries per litre or (pCi/L). When your results return from the lab, they will be expressed in that format, which will tell you what the average level of radon was during the time the test was active. Keep in mind, radon levels may fluctuate widely during a window as short as an hour and certainly may change due to seasonal, weather and other factors. This is why it is recommended to follow up your short-term test with a long-term test; one that is 90+ days long.

Although there is no safe level of radon gas in your home, the US EPA looks at 4.0 pCi/L as the theoretical action level for making a correction to your home. However, even if you achieve the 4.0 mark, EPA still strongly encourages you to consider striving for 2.0 pCi/L. You can see some of their views in the excerpt from the Radon Act 51 below:


[Radon Act 51 passed by Congress set the natural outdoor level of radon gas (0.4 pCi/L) as the target radon level for indoor radon levels. Unfortunately two-thirds of all homes exceed this level. The US EPA was tasked with setting practical guidelines and recommendations for the nation. To this end, the US EPA has set an action level of 4 pCi/L. At or above this level of radon, the EPA recommends you take corrective measures to reduce your exposure to radon gas. This does not imply that a level below 4.0 pCi/L is considered acceptable, as stated in the BEIR VI study. It is estimated that a reduction of radon levels to below 2 pCi/L nationwide would likely reduce the yearly lung cancer deaths attributed to radon by 50%. However, even with an action level of 2.0 pCi/L, the cancer risk presented by radon gas is still hundreds of times greater than the risks allowed for carcinogens in our food and water.]