Is it true or false that the action-level limit of 0.02 WL corresponds to a derived radon concentration of 4 pCi/L when the equilibrium ratio is 50%?

The statement is true. To understand why this is correct, it is important to know the relationship between working level (WL) and radon concentration (pCi/L) in the context of environmental radon measurement.

Working level is a measure of the potential alpha energy from radon decay products in the air. The action-level limit of 0.02 WL corresponds to a situation where the radon decay products in the environment pose a significant health risk. The concept of equilibrium ratio is also crucial here; when the equilibrium ratio is stated as 50%, it indicates that half of the radon decay products are in equilibrium with the radon gas present.

To find the corresponding radon concentration in picocuries per liter (pCi/L), you can use the average conversion factor. At an equilibrium ratio of 50%, the conversion factor is approximately 200 pCi/L per WL. Therefore, an action-level limit of 0.02 WL translates to a radon concentration of:

0.02 WL * 200 pCi/L = 4 pCi/L.

This calculation demonstrates the direct relationship between WL, the radon concentration, and the equilibrium ratio, confirming that the assertion is indeed true.