What is the equivalence between DAC and ALI?

What is the equivalence between DAC and ALI?

• A. 1 ALI
• B. 0.5 ALI
• C. 2 ALI
• D. 10 ALI

Answer: (A)

The key idea is how DAC is defined. Derived Air Concentration is the concentration of a radionuclide in air that would deliver the Annual Limit on Intake if that air is inhaled for a year. In other words, DAC is the air concentration that would exactly produce the ALI when breathed under the standard working-year conditions. Because of that definition, there’s a direct, one-to-one link between the two: specifying the ALI fixes the DAC and vice versa. Under the typical conventions used in these materials, this is expressed as a 1-to-1 equivalence, so the amount of activity described by the ALI corresponds to the DAC value in air.

The key idea is how DAC is defined. Derived Air Concentration is the concentration of a radionuclide in air that would deliver the Annual Limit on Intake if that air is inhaled for a year. In other words, DAC is the air concentration that would exactly produce the ALI when breathed under the standard working-year conditions. Because of that definition, there’s a direct, one-to-one link between the two: specifying the ALI fixes the DAC and vice versa. Under the typical conventions used in these materials, this is expressed as a 1-to-1 equivalence, so the amount of activity described by the ALI corresponds to the DAC value in air.