George Johnson, writing for the New York Times:
By Dr. Doss’s calculations, most residents would have received much less, about 4 millisieverts a year. The average annual exposure from the natural background radiation of the earth is 2.4 millisieverts.
How the added effect of the fallout would have compared with that of the evacuation depends on the validity of the “linear no-threshold model,” which assumes that any amount of radiation, no matter how small, causes some harm.
Dr. Doss is among scientists who question that supposition, one built into the world’s radiation standards. Below a certain threshold, they argue, low doses are harmless and possibly even beneficial — a long-debated phenomenon called radiation hormesis.
Interesting linear bias here.