Radiation meters may be calibrated in microsieverts
; 100,000 pSv sounds frightening, but it is 100 mSv, the minimal acute dose associated with a small, about 5%, increase in cancer risk, if delivered at a very high dose rate.
What does 40,000 microsieverts
of radiation do to a child?
(15) The problem is that the dose rate in microsieverts
per hour cannot be used to reassure on the basis of comparisons with annual natural background.
Sievert (Sv), a measure of radiation, was one of the most common terms in the crisis, with microsieverts
and millisieverts appearing in a high percentage of news stories.
March 20, almost all the readings were less than 15 microsieverts
In Tokyo, a metropolis of 13 mln people, a Reuters reading on Saturday morning showed ambient radiation of 0.22 microsieverts
per hour, about six times normal for the city.
Within the area, the team identified three spots where the radiation level was around 500 microsievert
per hour," Raina said.
A typical scan lasts about eight seconds and results in an effective dose of approximately 0.03 microsievert
(uSv)1 to the individual.
The estimated magnitude of increase was 1% per microsievert
per hour [95% confidence interval (CI), 0.7-1.2].
On the second and third floors, the inside readings were 0.1 and 0.3 microsievert
About 40 children commuting to two nurseries in central areas of Koriyama, where radiation of 0.9 microsievert
per hour is recorded, and their teachers took a bus to an educational facility some 30 kilometers away where the radiation level is 0.1 microsievert
Radiation levels in downtown Tokyo stood at 0.079 microsievert
an hour at 9