Japanese population dose from natural radiation
Level 5 - mechanism / opinion, no new human data
Dosimetric synthesis and modeling based on national survey data and reference estimates (by design analogy, not clinical CEBM)
OpenAlex W3005051569 · doi:10.1088/1361-6498/ab73b1
What was done
The authors synthesized and recalculated the annual effective radiation doses from natural sources for the Japanese population using updated data. They integrated cosmic-ray and thoron estimates from UNSCEAR and the Nuclear Safety Research Association, nationwide terrestrial radiation survey data from the National Institute of Radiological Sciences, and nationwide radon and foodstuff radionuclide survey data from the Japan Chemical Analysis Center (JCAC).
What was found
The total annual effective dose from natural radiation in Japan was estimated at 2.2 mSv (compared to the global average of 2.4 mSv). The component breakdowns were: - Dietary intake: 0.99 mSv - Inhalation: 0.59 mSv (0.50 mSv from radon, 0.09 mSv from thoron) - Terrestrial external radiation: 0.33 mSv - Cosmic-ray exposure: 0.29 mSv
Why it matters
This study establishes an updated, comprehensive baseline for natural background radiation exposure across Japan. It demonstrates that internal exposure via dietary intake constitutes the single largest fraction of natural radiation for the Japanese population.
Limits
The estimates rely on population-averaged modeling and standard dose conversion factors rather than individualized exposure measurements. Specific sample sizes and confidence intervals are not reported in the abstract, and thoron concentrations were derived from international reference values rather than direct domestic surveys.
Cited by
- supports Living at sea level provides an environmental background radiation exposure of approximately 1 to 2 millisieverts per year.