Yahoo Japan Corp. on Friday started showing real-time radiation levels at 11 locations in Japan on a special online map using data gathered by a group of academics in the wake of the crisis at the Fukushima Daiichi nuclear power plant. A Yahoo Japan official said the beta service, using data measured by a team from Keio University, is aimed at providing access to readings in addition to those released by the government. The readings, updated every five minutes, are taken at 11 points located mainly in northeastern and eastern Japan including Tokyo, Nihonmatsu in Fukushima Prefecture, Sendai and the city of Chiba. It will increase the number of observation points in the future, the official said.
See the site, http://radiation.yahoo.co.jp/.