DAC stands for which of the following?

• A. Derived Air Concentration
• B. Annual Dose
• C. Dose Allocation Coefficient
• D. Air Contaminant

Answer: (A)

Derived Air Concentration is the amount of a radionuclide in air that would deliver a specified committed dose to a person who breathes that air for a defined exposure period. It’s a reference value used to assess workplace air and to set ventilation, monitoring, and dose-control measures. DAC is usually expressed in activity per volume, such as Bq per cubic meter, and it ties the airborne concentration directly to the dose constraint you’re aiming to meet (for example an annual dose limit). This makes it a practical tool for evaluating whether air contamination levels are acceptable and for planning protective controls. The other options don’t fit because they describe total dose concepts, coefficients, or general contaminants rather than a concentration in air linked to a dose outcome.