The BBC has an interesting discussion about the rights and wrongs of the Fukushima exclusion zone. On one hand you protect people from radiation dose and on the other you deprive them of their home. At what level of radiation dose does exclusion become the “right” choice?
The article talks about measurable radiation dose so I believe it is talking about gamma shine from contaminated surfaces. We’d also be interested in the internal doses received by people in the area.
See BBC article here.