What is the average indoor radon level typically measured in pCi/L?

The typical average indoor radon level is approximately 1.3 pCi/L. This figure is significant as it represents a baseline for assessing radon exposure in residential and indoor environments. The U.S. Environmental Protection Agency (EPA) considers radon levels below 2 pCi/L to be relatively safe, whereas levels of 4.0 pCi/L and above are recommended for action due to increased health risks, particularly the risk of lung cancer with prolonged exposure.

Understanding this average level is crucial for health professionals and radon mitigation experts, as it helps in advising homeowners and residents on the need for testing and potential remediation actions. The other figures presented do not reflect typical residential averages; for example, 4.0 pCi/L is recognized as a threshold for triggering action rather than a common average. The larger numbers, like 100.3 pCi/L, would be considered alarmingly high, indicating a severe radon problem, while 2.22 pCi/L is above average but doesn’t represent the typical level that would prompt broad concern in the general population. Thus, the figure of 1.3 pCi/L serves as the standard reference point for evaluating indoor radon levels.