Indoor Radon Concentration
The chart below shows the results of indoor radon concentration surveys conducted over a period of about 3 years from April 1993 to June 1996, for 20 households each in all the prefectures in Japan.
Indoor radon concentration changes by ventilation and building materials used. The exposure dose calculated from these survey results was about 1/3 of the global average (UNSCEAR 1993).
Frequency distribution of indoor radon concentration in Japan
Sources of Survey Results
- Radon Concentration Level Survey Comprehensive Commission Results Report (FY1992-FY1996 Survey Results)
- Final Report on Radon Concentration Nationwide Survey, FY1992-FY1996 Indoor Radon Concentration National Survey, National Institute of Radiological Sciences Radon Concentration and Dose Evaluation Committee, NIRS-R-32
Outdoor Radon Concentration
The chart below shows the results of outdoor radon concentration surveys conducted over a period from FY1997 to FY1999, for 15 locations each in all the prefectures in Japan.
The exposure dose calculated from these survey results was about 1/4 of the indoor values.
Frequency distribution of outdoor radon concentration in Japan
Sources of Survey Results
- Radon Concentration Measurement Survey Results Report (FY1997)
- Radon Concentration Measurement Survey Results Report (FY1998)
- Radon Concentration Measurement Survey Results Report (FY1999)
- Radon Concentration Measurement Survey Results Report (FY2000)
Workplace Environment Radon Concentration
The chart below shows the results of radon concentration surveys conducted over a period from FY2000 to FY2002, for 700 workplaces in Japan.
This survey was conducted for offices, factories, hospitals, and schools taking into account the number of workers based on the census information.
Frequency distribution of workplace environment radon concentration in Japan
Sources of Survey Results
- Radon Concentration Measurement Survey Results Report (FY1997)
- Radon Concentration Measurement Survey Results Report (FY1998)
- Radon Concentration Measurement Survey Results Report (FY1999)
- Radon Concentration Measurement Survey Results Report (FY2000)