What term describes the exposure of large populations to ionizing radiation?

The term that accurately describes the exposure of large populations to ionizing radiation is collective dose. Collective dose is a measure that combines the number of individuals exposed to radiation and the dose they receive, usually expressed in units of person-sieverts or person-rem. This metric is particularly useful in assessing public health risks associated with radiation exposure across groups or communities, allowing for a better understanding of the potential impact on population health from a specified radiation source or event.

In contrast, person-rem specifically refers to the dose received by an individual, and is typically used in the context of dose from occupational exposure or specific situations rather than broad population exposure. An occupational dose pertains only to doses received by workers as a result of their job-related activities and does not encompass the wider population. Finally, the term radiation burden generally refers to the total amount of radiation exposure an individual has received, but is not specifically aimed at populations. Thus, the most appropriate choice to describe exposure to large populations is collective dose.