What is the formula for equilibrium ratio (ER)?

The equilibrium ratio (ER) is a crucial concept in radon measurement because it helps to describe the relationship between radon concentration in the air, measured in picocuries per liter (pCi/L), and the corresponding working level (WL) of radon decay products. The correct formula captures this relationship effectively.

The formula ER = (WL x 100) / (pCi/L) indicates that the equilibrium ratio is derived by taking the working level, multiplying it by 100 to convert decaying radon products into a comparable scale, and then dividing it by the radon concentration (pCi/L). This formulation reflects the proportionality between the two measurements, allowing the assessment of how closely radon decay products are in equilibrium with the radon concentration itself.

Understanding this ratio is important for interpreting measurement results and assessing radon exposure risks accurately. It underscores the balance between the radioactive decay of radon in the air and the radiation levels individuals may be exposed to in a location, assisting in determining necessary remediation actions if high levels are present.