Base Information Q&A SiteJAEA

Case of Juman Mountain Forest Fire in 2017


How much does additional internal dose exposure would be if we assume highest concentration during the fire event was exposed? How harmful for the health?

Effect was considered to be very small, based on the evaluation of internal exposure dose using highest monitoring value.

  • Internal dose exposure was evaluated conservatively based on the results of highest radio-cesium concentration during the fire event.
  • It was evaluated extremely smaller than the value of internal dose exposure (0.48 mSv) from natural radioactive materials annually.
Measurement location Internal dose exposure [mSv/day]
Yasuragi hall 0.000097
Ishikuma hall 0.00031
Nogami-ichikuchiku hall 0.000020

Internal dose exposure [mSv/day]
 = Radio-cesium concentration in dust [mBq/m3] × respiration rate (22.2m3/day) × effective dose equivalent [mSv/Bq] ÷ 1000

※effective dose equivalent(134Cs:0.000020, 137Cs:0.000039)
※Assumption:8 hour work per day for 250 days per year at the highest monitoring point with continuous intake.