Which of the following is a method to calculate the equilibrium ratio (ER) of radon and decay products?

The equilibrium ratio (ER) is an important concept in the understanding of radon gas and its decay products. The correct method to calculate the equilibrium ratio is through the formula that relates the concentrations of radon and its decay products.

Using the formula ER = (RDP concentration) x (100) / (Radon concentration) allows for the assessment of how much of the radon gas has decayed into its radioactive daughters, or decay products (RDP). This calculation is essential because it indicates the potential health risks associated with radon exposure. The resulting ER value gives a percentage that reflects the amount of decay products that exists in equilibrium with the parent radon gas at a given time.

This method effectively captures the relationship between the concentration of radon and its decay products. In scenarios where concentration is measured in Bq/m³ (Becquerels per cubic meter), this equation allows practitioners to derive a useful percentage that can inform mitigation efforts and health risk assessments.

By contrast, the other options do not accurately represent the relationship needed to calculate the equilibrium ratio. Hence, the correct formula emphasizes the significance of understanding both radon and its decay products to evaluate exposure risks effectively.