What is the equivalence between 2000 DAC and ALI?

What is the equivalence between 2000 DAC and ALI?

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

Answer: (A)

In radiation protection, ALI is the maximum activity a person may intake in a year, while DAC is the air concentration that would deliver that same annual intake if breathed for a standard working year. The standard working year is taken as about 2000 hours. So, if you breathe air containing 1 DAC for the full 2000 hours, your intake equals 1 ALI. That’s why 2000 DAC is defined to equal 1 ALI. Other values would require changing the assumed breathing time or rate, which isn’t how the relationship is defined.

In radiation protection, ALI is the maximum activity a person may intake in a year, while DAC is the air concentration that would deliver that same annual intake if breathed for a standard working year. The standard working year is taken as about 2000 hours. So, if you breathe air containing 1 DAC for the full 2000 hours, your intake equals 1 ALI. That’s why 2000 DAC is defined to equal 1 ALI. Other values would require changing the assumed breathing time or rate, which isn’t how the relationship is defined.