United Nations Scientific Committee on the Effects of Atomic Radiation

ATTACHMENT A-4

JAPAN-SPECIFIC DATAUNSCEAR 2020/2021 Report, annex B, Levels and effects of radiation exposuredue to the accident at the Fukushima Daiichi Nuclear Power Station: implicationsof information published since the UNSCEAR 2013 Report
Contents
This attachment provides Japan-specific data relevant to the estimation of internal and external
exposure of the Japanese population as a result of the accident at the Fukushima Daiichi Nuclear
Power Station (FDNPS). Firstly, dose coefficients for intake of radioiodine (in different
physical/chemical forms) and radiotellurium by inhalation or ingestion are presented. The dosecoefficients have been derived using the methodology set out in section IV of attachment A-2
and should be regarded as indicative for Japanese people with differing diet, age and sex.
Secondly, information is presented on the occupancy of Japanese people (of differing age-socialgroupings) inside buildings (e.g., at home, work, leisure). Based on this latter information,
improved estimates have been made of occupancy factors to be used when updating the dose
estimates in the UNSCEAR 2013 Report [UNSCEAR, 2014].
Notes
For consistency, doses and other quantities in this attachment are quoted, in general, to two
significant figures. This should not be interpreted as an indication of their precision that may
often be much less.
The designations employed and the presentation of material in this publication do not imply theexpression of any opinion whatsoever on the part of the Secretariat of the United Nations
concerning the legal status of any country, territory, city or area, or of its authorities, orconcerning the delimitation of its frontiers or boundaries.
Information on Uniform Resource Locators (URLs) and links to Internet sites contained in thepresent publication are provided for the convenience of the reader and are correct at the time ofissue. The United Nations takes no responsibility for the continued accuracy of that informationor for the content of any external website.
© United Nations, April 2022. All rights reserved, worldwide.
This attachment has not been formally edited.

CONTENTS

I. JAPAN-SPECIFIC INDICATIVE DOSE COEFFICIENTS FOR INTAKES OF
RADIOIODINE AND RADIOTELLURIUM ....................................................................... 5
A. Japan-specific indicative dose coefficients for 131I .......................................................... 5
B. Japan-specific indicative dose coefficients for 132I .......................................................... 7
C. Japan-specific indicative dose coefficients for 133I ........................................................ 10
D. Japan-specific indicative dose coefficients for 132Te ..................................................... 12
II. JAPAN-SPECIFIC OCCUPANCY FACTORS .................................................................. 14
A. UNSCEAR 2013 Report – occupancy factors for Japan ................................................ 14
B. Review of publications by Japanese authors since 2013 relevant for theassessment of occupancy factors .................................................................................... 15
C. Discussion ...................................................................................................................... 18
REFERENCES ........................................................................................................................... 21

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

5I.

JAPAN-SPECIFIC INDICATIVE DOSE COEFFICIENTS FORINTAKES OF RADIOIODINE AND RADIOTELLURIUM

A.

Japan-specific indicative dose coefficients for 131I

Table A-4.1. Japan-specific indicative dose coefficients for inhalation of 131I by members of the
public (adult and 10-year-old) with various levels of dietary intake of stable iodine: thyroid
absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
Adult male,absorbed dose tothyroid per
exposure

Adult female,absorbed dose tothyroid per
exposure

Adult,
effective dose
per exposure

10-year-old,absorbed doseto thyroid per
exposure

10-year-old,
effective dose
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

3.9E-11

3.8E-11

1.8E-12

6.9E-11

2.9E-12

Typical2.1E-112.0E-11

9.6E-13

3.7E-11

1.6E-12

Kelp-rich diet

7.2E-12

6.9E-12

3.4E-13

1.3E-11

5.9E-13

Inhalation, methyl iodide, dietary intake of stable iodine
Western pattern diet

6.6E-11

6.4E-11

3.0E-12

1.1E-10

4.4E-12

Typical

3.6E-11

3.4E-11

1.6E-12

5.8E-11

2.4E-12

Kelp-rich diet

1.2E-11

1.2E-11

5.6E-132.0E-11

8.2E-13

Inhalation, elemental iodine, dietary intake of stable iodine
Western pattern diet

9.4E-11

9.1E-11

4.2E-12

1.5E-10

6.6E-12

Typical

5.1E-11

4.9E-11

2.3E-12

8.3E-11

3.7E-12

Kelp-rich diet

1.7E-11

1.7E-11

8.2E-13

2.8E-11

1.5E-12

Table A-4.2. Japan-specific indicative dose coefficients for inhalation of 131I by members of the
public (1-year-old and fetus 35 weeks) with various levels of dietary intake of stable iodine:
thyroid absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
1-year-old, absorbed
dose to thyroid per
exposure

1-year-old,
effective dose per
exposure

Fetus 35 weeks,absorbed dose to thyroid
per maternal exposure

Fetus 35 weeks,
effective dose permaternal exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

9.1E-11

3.8E-12

7.7E-11

3.8E-12

Typical

4.8E-112.0E-12

2.9E-11

1.4E-12

Kelp-rich diet

1.6E-11

7.4E-13

Inhalation, methyl iodide, dietary intake of stable iodine
Western pattern diet

1.3E-10

5.1E-12

1.6E-10

7.9E-12

Typical

6.7E-11

2.7E-12

5.9E-11

3.0E-12

Kelp-rich diet

2.2E-11

9.2E-13

6

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

1-year-old, absorbed
dose to thyroid per
exposure

1-year-old,
effective dose per
exposure

Fetus 35 weeks,absorbed dose to thyroid
per maternal exposure

Fetus 35 weeks,
effective dose permaternal exposure

Inhalation, elemental iodine, dietary intake of stable iodine
Western pattern diet

1.8E-10

7.5E-122.0E-101.0E-11

Typical

9.5E-11

4.1E-12

7.6E-11

3.8E-12

Kelp-rich diet

3.2E-11

1.5E-12

Table A-4.3. Japan-specific indicative dose coefficients for inhalation of 131I by adult members of
the public with the typical level of dietary intake of stable iodine: organ absorbed dose per
exposure, Gy per (Bq s/m3)
Adult male,absorbed
dose to redbone marrow
per exposure

Adult female,absorbed
dose to redbone marrow
per exposure

Adult male,absorbed
dose to colon
per exposure

Adult female,absorbed
dose to colon
per exposure

Adult male,absorbed
dose to breast
per exposure

Adult female,absorbed
dose to breast
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical1.4E-14

1.4E-14

6.0E-15

4.9E-15

5.0E-15

7.8E-15

7.8E-15

1.2E-14

1.1E-14

1.8E-14

Inhalation, methyl iodide, dietary intake of stable iodine
Typical2.3E-14

2.2E-14

9.4E-15

7.8E-15

Inhalation, elemental iodine, dietary intake of stable iodine
Typical

3.3E-14

3.2E-14

1.4E-14

1.2E-14

Table A-4.4. Japan-specific indicative dose coefficients for inhalation of 131I by children with thetypical level of dietary intake of stable iodine: organ absorbed dose per exposure,
Gy per (Bq s/m3)
10-year-old,absorbed
dose to redbone marrow
per exposure

10-year-old,absorbed
dose to colon
per exposure

10-year-old,absorbed
dose to breast
per exposure

1-year-old,absorbed
dose to redbone marrow
per exposure

1-year-old,absorbed
dose to colon
per exposure

1-year-old,absorbed
dose to breast
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical1.3E-14

8.3E-15

6.8E-15

1.6E-14

1.1E-14

8.2E-15

1.4E-14

1.0E-14

2.1E-14

1.5E-14

Inhalation, methyl iodide, dietary intake of stable iodine
Typical2.0E-14

1.2E-14

9.7E-15

2.0E-14

Inhalation, elemental iodine, dietary intake of stable iodine
Typical2.8E-14

1.8E-14

1.4E-14

2.9E-14

Table A-4.5. Japan-specific indicative dose coefficients for ingestion of 131I by members of the
public (adult and 10-year-old) with various levels of dietary intake of stable iodine: thyroid
absorbed dose per intake, Gy /Bq, and effective dose per intake, Sv/Bq
Adult male,absorbed dose tothyroid per intake

Adult female,absorbed doseto thyroid per
intakeAdult, effective
dose per intake

10-year-old,absorbed doseto thyroid per
intake10-year-old,
effective dose
per intake

Western pattern diet

3.6E-07

4.4E-07

1.6E-08

8.7E-07

3.5E-08

Typical2.0E-07

2.3E-078.8E-09

4.6E-07

1.9E-08

Kelp-rich diet

6.7E-088.0E-08

3.1E-09

1.6E-07

6.6E-09

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

7

Table A-4.6. Japan-specific indicative dose coefficients for ingestion of 131I by members of the
public (1-year-old and fetus 35 weeks) with various levels of dietary intake of stable iodine:
thyroid absorbed dose per intake, Gy/Bq, and effective dose per intake, Sv/Bq
1-year-old, absorbed
dose to thyroid per
intake1-year-old,
effective dose per
intakeFetus 35 weeks,absorbed dose tothyroid permaternal intake

Fetus 35 weeks,
effective dose permaternal intake

Western pattern diet

3.0E-06

1.2E-07

1.1E-06

5.5E-08

Typical1.6E-06

6.4E-08

4.1E-072.0E-08

Kelp-rich diet

5.3E-07

2.2E-08

Table A-4.7. Japan-specific indicative dose coefficients for ingestion of 131I by adult members of
the public with the typical level of dietary intake of stable iodine: organ absorbed dose per
intake, Gy/Bq
Adult male,absorbed doseto red bonemarrow per
intakeAdult female,absorbed doseto red bonemarrow per
intakeAdult male,absorbed doseto colon per
intakeAdult female,absorbed doseto colon per
intakeAdult male,absorbed doseto breast per
intakeAdult female,absorbed doseto breast per
intake1.3E-10

1.5E-10

6.4E-11

6.3E-11

4.6E-11

8.6E-11

TypicalTable A-4.8. Japan-specific indicative dose coefficients for ingestion of 131I by children with thetypical level of dietary intake of stable iodine: organ absorbed dose per intake, Gy/Bq
10-year-old,absorbed doseto red bonemarrow per
intake10-year-old,absorbed doseto colon per
intake10-year-old,absorbed doseto breast per
intake1-year-old,absorbed doseto red bonemarrow per
intake1-year-old,absorbed doseto colon per
intake1-year-old,absorbed doseto breast per
intake1.6E-10

1.2E-108.0E-11

4.8E-10

3.7E-10

2.5E-10

TypicalB.

Japan-specific indicative dose coefficients for 132I

Table A-4.9. Japan-specific indicative dose coefficients for inhalation of 132I by members of the
public (adult and 10-year-old) with various levels of dietary intake of stable iodine: thyroid
absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
Adult male,absorbed dose tothyroid per
exposure

Adult female,absorbed dose tothyroid per
exposure

Adult, effective
dose perexposure

10-year-old,absorbed dose tothyroid per
exposure

10-year-old,
effective dose
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

2.8E-13

2.7E-13

2.2E-14

4.7E-13

8.1E-14

Typical1.3E-13

1.3E-13

1.5E-14

2.3E-13

7.2E-14

Kelp-rich diet

4.4E-14

4.3E-14

1.2E-14

7.4E-14

6.6E-14

Inhalation, methyl iodide, dietary intake of stable iodine
Western pattern diet

7.3E-13

7.0E-13

4.6E-14

1.2E-12

6.5E-14

Typical

3.5E-13

3.4E-13

2.9E-14

5.9E-13

4.0E-14

Kelp-rich diet

1.1E-13

1.1E-13

1.9E-14

1.9E-13

2.5E-14

8

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

Adult male,absorbed dose tothyroid per
exposure

Adult female,absorbed dose tothyroid per
exposure

10-year-old,absorbed dose tothyroid per
exposure

Adult, effective
dose perexposure

10-year-old,
effective dose
per exposure

Inhalation, elemental iodine, dietary intake of stable iodine
Western pattern diet

9.2E-13

8.9E-13

8.5E-14

1.5E-12

7.1E-13

Typical

4.4E-13

4.3E-13

6.4E-14

7.4E-13

6.8E-13

Kelp-rich diet

1.4E-13

1.4E-13

5.1E-14

2.4E-13

6.6E-13

Table A-4.10. Japan-specific indicative dose coefficients for inhalation of 132I by members of the
public (1-year-old and fetus 35 weeks) with various levels of dietary intake of stable iodine:
thyroid absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
1-year-old, absorbed
dose to thyroid per
exposure

1-year-old,
effective dose per
exposure

Fetus 35 weeks,absorbed dose tothyroid permaternal exposure

Fetus 35 weeks,
effective dose permaternal exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

7.0E-13

8.6E-14

8.5E-13

4.5E-14

Typical

3.4E-13

7.2E-14

2.3E-13

1.4E-14

Kelp-rich diet

1.1E-13

6.3E-14

Inhalation, methyl iodide, dietary intake of stable iodine
Western pattern diet

1.6E-128.0E-14

1.9E-121.0E-13

Typical

7.9E-13

4.6E-14

5.1E-13

3.1E-14

Kelp-rich diet

2.5E-13

2.4E-14––

Inhalation, elemental iodine, dietary intake of stable iodine
Western pattern diet

2.1E-12

5.1E-13

2.2E-12

1.2E-13

Typical1.0E-12

4.7E-13

6.1E-13

3.7E-14

Kelp-rich diet

3.2E-13

4.4E-13

Table A-4.11. Japan-specific indicative dose coefficients for inhalation of 132I by adult membersof the public with the typical level of dietary intake of stable iodine: organ absorbed dose per
exposure, Gy per (Bq s/m3)
Adult male,absorbed doseto red bonemarrow per
exposure

Adult female,absorbed doseto red bonemarrow per
exposure

Adult male,absorbed doseto colon per
exposure

Adult female,absorbed doseto colon per
exposure

Adult male,absorbed doseto breast per
exposure

Adult female,absorbed doseto breast per
exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical

3.5E-15

3.8E-15

3.1E-15

2.3E-15

2.1E-15

2.1E-15

3.7E-15

3.3E-15

6.0E-15

4.9E-15

Inhalation, methyl iodide, dietary intake of stable iodine
Typical

7.3E-15

7.7E-15

6.7E-15

5.7E-15

Inhalation, elemental iodine, dietary intake of stable iodine
Typical1.0E-14

1.1E-14

1.0E-14

7.7E-15

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

9Table A-4.12. Japan-specific indicative dose coefficients for inhalation of 132I by children with thetypical level of dietary intake of stable iodine: organ absorbed dose per exposure,
Gy per (Bq s/m3)
10-year-old,absorbed doseto red bonemarrow per
exposure

10-year-old,absorbed doseto colon per
exposure

1-year-old,absorbed doseto red bonemarrow per
exposure

10-year-old,absorbed doseto breast per
exposure

1-year-old,absorbed doseto colon per
exposure

1-year-old,absorbed doseto breast per
exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical

4.3E-15

3.6E-15

2.6E-15

4.6E-15

3.6E-15

2.6E-15

7.3E-15

3.8E-15

1.0E-14

5.4E-15

Inhalation, methyl iodide, dietary intake of stable iodine
Typical

8.1E-15

8.0E-15

4.1E-15

7.0E-15

Inhalation, elemental iodine, dietary intake of stable iodine
Typical1.1E-14

1.2E-14

5.9E-15

9.6E-15

Table A-4.13. Japan-specific indicative dose coefficients for ingestion of 132I by members of the
public (adult and 10-year-old) with various levels of dietary intake of stable iodine: thyroid
absorbed dose per intake, Gy/Bq, and effective dose per intake, Sv/Bq
Adult male,absorbed dose tothyroid per
intakeAdult female,absorbed dose tothyroid per
intakeAdult, effective
dose per intake

10-year-old,absorbed dose tothyroid per
intake10-year-old,
effective dose
per intake

Western pattern diet

2.9E-09

3.5E-09

2.8E-10

7.1E-09

5.8E-10

Typical1.4E-09

1.7E-09

2.1E-10

3.4E-09

4.3E-10Kelp-rich diet

4.5E-10

5.5E-10

1.7E-10

1.1E-09

3.4E-10

Table A-4.14. Japan-specific indicative dose coefficients for ingestion of 132I by members of the
public (1-year-old and fetus 35 weeks) with various levels of dietary intake of stable Iodine:
thyroid absorbed dose per intake, Gy/Bq, and effective dose per intake, Sv/Bq
1-year-old, absorbed
dose to thyroid per
intake1-year-old,
effective dose per
intakeFetus 35 weeks, absorbed
dose to thyroid permaternal intake

Fetus 35 weeks,
effective dose permaternal intake

Western pattern diet

2.8E-08

1.7E-09

1.2E-08

6.2E-10

Typical1.4E-08

1.1E-09

3.2E-09

2.0E-10Kelp-rich diet

4.4E-09

7.6E-10

Table A-4.15. Japan-specific indicative dose coefficients for ingestion of 132I by adult membersof the public with the typical level of dietary intake of stable Iodine: organ absorbed dose per
intake, Gy/Bq

TypicalAdult male,absorbed
dose to redbone marrow
per intake

Adult female,absorbed
dose to redbone marrow
per intake

Adult male,absorbed
dose to colon
per intake

Adult female,absorbed
dose to colon
per intake

Adult male,absorbed
dose tobreast per
intakeAdult female,absorbed
dose tobreast per
intake3.6E-11

4.8E-11

5.0E-11

3.9E-11

2.8E-11

2.5E-11

10

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

Table A-4.16. Japan-specific indicative dose coefficients for ingestion of 132I by children with thetypical level of dietary intake of stable Iodine: organ absorbed dose per intake, Gy/Bq

TypicalC.

10-year-old,absorbed
dose to redbone marrow
per intake

10-year-old,absorbed
dose to colon
per intake

10-year-old,absorbed
dose tobreast per
intake1-year-old,absorbed
dose to redbone marrow
per intake

1-year-old,absorbed
dose to colon
per intake

1-year-old,absorbed
dose tobreast per
intake5.5E-11

7.8E-11

3.6E-11

1.4E-10

1.9E-10

9.5E-11

Japan-specific indicative dose coefficients for 133I

Table A-4.17. Japan-specific indicative dose coefficients for inhalation of 133I by members of the
public (adult and 10-year-old) with various level of dietary intake of stable iodine: thyroid
absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
Adult male,absorbed dose tothyroid per
exposure

Adult female,absorbed doseto thyroid per
exposure

Adult, effective
dose perexposure

10-year-old,absorbed doseto thyroid per
exposure

10-year-old,
effective dose
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

6.6E-12

6.4E-12

3.1E-13

1.2E-11

6.0E-13

Typical

3.5E-12

3.3E-12

1.7E-13

6.3E-12

3.7E-13

Kelp-rich diet

1.2E-12

1.1E-12

7.2E-14

2.1E-122.0E-13

Inhalation, methyl iodide, dietary intake of stable iodine
Western pattern diet

1.2E-11

1.2E-11

5.8E-13

2.1E-11

8.9E-13

Typical

6.5E-12

6.3E-12

3.2E-13

1.1E-11

4.9E-13

Kelp-rich diet

2.2E-12

2.1E-12

1.2E-13

3.7E-12

1.9E-13

Inhalation, elemental iodine, dietary intake of stable iodine
Western pattern diet

1.7E-11

1.7E-11

8.4E-133.0E-11

1.8E-12

Typical9.2E-128.8E-12

4.7E-13

1.6E-11

1.2E-12

Kelp-rich diet

3.1E-12

2.9E-122.0E-13

5.3E-12

8.3E-13

Table A-4.18. Japan-specific indicative dose coefficients for inhalation of 133I by members of the
public (1-year-old and fetus 35 weeks) with various level of dietary intake of stable iodine:
thyroid absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
1-year-old, absorbed
dose to thyroid per
exposure

1-year-old,
effective dose per
exposure

Fetus 35 weeks,absorbed dose tothyroid permaternal exposure

Fetus 35 weeks,
effective dose permaternal exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

1.9E-11

8.6E-13

1.8E-11

9.0E-13

Typical

9.8E-125.0E-13

6.3E-12

3.2E-13

Kelp-rich diet

3.3E-12

2.4E-13

Inhalation, methyl iodide, dietary intake of stable iodine
Western pattern diet

2.9E-11

1.2E-12

3.7E-11

1.9E-12

Typical1.5E-11

6.4E-13

1.3E-11

6.6E-13

Kelp-rich diet

5.1E-12

2.4E-13

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

1-year-old, absorbed
dose to thyroid per
exposure

1-year-old,
effective dose per
exposure

11

Fetus 35 weeks,absorbed dose tothyroid permaternal exposure

Fetus 35 weeks,
effective dose permaternal exposure

Inhalation, elemental iodine, dietary intake of stable iodine
Western pattern diet

4.1E-11

2.1E-12

4.7E-11

2.4E-12

Typical2.1E-11

1.3E-12

1.7E-11

8.4E-13

Kelp-rich diet

7.2E-12

7.1E-13--

Table A-4.19. Japan-specific indicative dose coefficients for inhalation of 133I by adult membersof the public with the typical level of dietary intake of stable iodine: organ absorbed dose per
exposure, Gy per (Bq s/m3)
Adult male,absorbed doseto red bonemarrow per
exposure

Adult female,absorbed doseto red bonemarrow per
exposure

Adult male,absorbed doseto colon per
exposure

Adult female,absorbed doseto colon per
exposure

Adult male,absorbed doseto breast per
exposure

Adult female,absorbed doseto breast per
exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical

6.4E-15

6.4E-15

5.8E-15

5.0E-15

3.4E-15

3.6E-15

5.5E-15

5.6E-15

8.2E-15

8.2E-15

Inhalation, methyl iodide, dietary intake of stable iodine
Typical1.1E-14

1.1E-14

9.8E-15

8.6E-15

Inhalation, elemental iodine, dietary intake of stable iodine
Typical1.6E-14

1.6E-14

1.5E-14

1.3E-14

Table A-4.20. Japan-specific indicative dose coefficients for inhalation of 133I by children with thetypical level of dietary intake of stable iodine: organ absorbed dose per exposure,
Gy per (Bq s/m3)
10-year-old,absorbed doseto red bonemarrow per
exposure

10-year-old,absorbed doseto colon per
exposure

10-year-old,absorbed doseto breast per
exposure

1-year-old,absorbed doseto red bonemarrow per
exposure

1-year-old,absorbed doseto colon per
exposure

1-year-old,absorbed doseto breast per
exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical

7.7E-15

7.6E-15

4.7E-15

9.1E-15

7.8E-15

5.3E-15

1.1E-14

7.0E-15

1.7E-14

1.0E-14

Inhalation, methyl iodide, dietary intake of stable iodine
Typical1.2E-14

1.2E-14

7.0E-15

1.2E-14

Inhalation, elemental iodine, dietary intake of stable iodine
Typical1.7E-14

1.8E-14

1.0E-14

1.7E-14

Table A-4.21. Japan-specific indicative dose coefficients for ingestion of 133I by members of the
public (adult and 10-year-old) with various levels of dietary intake of stable iodine: thyroid
absorbed dose per intake, Gy/Bq, and effective dose per intake, Sv/Bq
Adult male,absorbed dose tothyroid per
intakeAdult female,absorbed dose tothyroid per
intakeAdult, effective
dose per intake

10-year-old,absorbed dose tothyroid per
intake10-year-old,
effective dose
per intake

Western pattern diet

6.6E-088.0E-08

3.1E-09

1.6E-077.0E-09

Typical

3.5E-08

4.2E-08

1.8E-09

8.6E-08

3.9E-09

Kelp-rich diet

1.2E-08

1.4E-08

7.4E-10

2.9E-08

1.6E-09

12

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

Table A-4.22. Japan-specific indicative dose coefficients for ingestion of 133I by members of the
public (1-year-old and fetus 35 weeks) with various levels of dietary intake of stable iodine:
thyroid absorbed dose per intake, Gy/Bq, and effective dose per intake, Sv/Bq
1-year-old,absorbed dose tothyroid per intake

1-year-old, effective
dose per intake

Fetus 35 weeks, absorbed
dose to thyroid permaternal intake

Fetus 35 weeks, effective
dose per maternal intake

Western pattern diet

6.7E-07

2.8E-08

2.5E-07

1.3E-08

Typical

3.5E-07

1.5E-08

8.9E-08

4.5E-09

Kelp-rich diet

1.2E-07

5.6E-09

Table A-4.23. Japan-specific indicative dose coefficients for ingestion of 133I by adult membersof the public with the typical level of dietary intake of stable Iodine: organ absorbed dose per
intake, Gy/Bq

TypicalAdult male,absorbed
dose to redbone marrow
per intake

Adult female,absorbed
dose to redbone marrow
per intake

Adult male,absorbed
dose to colon
per intake

Adult female,absorbed
dose to colon
per intake

Adult male,absorbed
dose tobreast per
intakeAdult female,absorbed
dose tobreast per
intake6.0E-11

7.5E-11

7.0E-11

7.2E-11

3.4E-11

4.0E-11

Table A-4.24. Japan-specific indicative dose coefficients for ingestion of 133I by children with thetypical level of dietary intake of stable Iodine: organ absorbed dose per intake, Gy/Bq

TypicalD.

10-year-old,absorbed
dose to redbone marrow
per intake

10-year-old,absorbed
dose to colon
per intake

10-year-old,absorbed
dose tobreast per
intake1-year-old,absorbed
dose to redbone marrow
per intake

1-year-old,absorbed
dose to colon
per intake

1-year-old,absorbed
dose tobreast per
intake9.6E-11

1.2E-10

5.8E-11

2.9E-10

3.1E-10

1.7E-10

Japan-specific indicative dose coefficients for 132Te

Table A-4.25. Japan-specific indicative dose coefficients for inhalation of 132Te by members of
the public (adult and 10-year-old) with various level of dietary intake of stable iodine: thyroid
absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
Adult male,absorbed dose tothyroid per
exposure

Adult female,absorbed doseto thyroid per
exposure

Adult, effective
dose perexposure

10-year-old,absorbed doseto thyroid per
exposure

10-year-old,
effective dose
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

4.3E-12

4.1E-12

3.1E-13

7.3E-12

5.7E-13

Typical2.1E-122.0E-122.2E-13

3.6E-12

4.2E-13

Kelp-rich diet

7.4E-13

7.2E-13

1.6E-13

1.3E-12

3.3E-13

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

13

Table A-4.26. Japan-specific indicative dose coefficients for inhalation of 132Te by members of
the public (1-year-old and fetus 35 weeks) with various level of dietary intake of stable iodine:
thyroid absorbed dose per exposure, Gy per (Bq s/m3), and effective dose per exposure,
Sv per (Bq s/m3)
1-year-old, absorbed
dose to thyroid per
exposure

Fetus 35 weeks,absorbed dose tothyroid permaternal exposure

1-year-old,
effective dose per
exposure

Fetus 35 weeks,
effective dose permaternal exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Western pattern diet

1.1E-11

7.2E-13

2.3E-11

1.2E-12

Typical

5.4E-12

4.9E-13

5.9E-12

3.7E-13

Kelp-rich diet

1.9E-12

3.5E-13

Table A-4.27. Japan-specific indicative dose coefficients for inhalation of 132Te by adultmembers of the public with the typical level of dietary intake of stable iodine: organ absorbed
dose per exposure, Gy per (Bq s/m3)
Adult male,absorbed
dose to redbone marrow
per exposure

Adult female,absorbed
dose to redbone marrow
per exposure

Adult male,absorbed
dose to colon
per exposure

Adult female,absorbed
dose to colon
per exposure

Adult male,absorbed
dose to breast
per exposure

Adult female,absorbed
dose to breast
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical

6.5E-14

7.1E-14

1.8E-13

1.7E-13

3.2E-14

2.6E-14

Table A-4.28. Japan-specific indicative dose coefficients for inhalation of 132Te by children withthe typical level of dietary intake of stable iodine: organ absorbed dose per exposure,
Gy per (Bq s/m3)
10-year-old,absorbed
dose to redbone marrow
per exposure

10-year-old,absorbed
dose to colon
per exposure

10-year-old,absorbed
dose to breast
per exposure

1-year-old,absorbed
dose to redbone marrow
per exposure

1-year-old,absorbed
dose to colon
per exposure

1-year-old,absorbed
dose to breast
per exposure

Inhalation, aerosols Type F, 1 µm, dietary intake of stable iodine
Typical

7.8E-14

2.5E-13

3.7E-14

8.4E-142.0E-13

3.8E-14

Table A-4.29. Japan-specific indicative dose coefficients for ingestion of 132Te by members of
the public (adult and 10-year-old) with various levels of dietary intake of stable iodine: thyroid
absorbed dose per intake, Gy/Bq, and effective dose per intake, Sv/Bq
Adult male,absorbed dose tothyroid per
intakeAdult female,absorbed dose tothyroid per
intakeAdult, effective
dose per intake

10-year-old,absorbed dose tothyroid per
intake10-year-old,
effective dose per
intakeWestern pattern diet

2.0E-08

2.4E-08

1.9E-09

4.9E-08

3.6E-09

Typical

9.8E-09

1.2E-08

1.5E-09

2.4E-08

2.6E-09

Kelp-rich diet

3.4E-09

4.1E-09

1.2E-09

8.3E-09

2.0E-09

14

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

Table A-4.30. Japan-specific indicative dose coefficients for ingestion of 132Te by members of
the public (1-year-old and fetus 35 weeks) with various levels of dietary intake of stable iodine:
thyroid absorbed dose per intake, Gy/Bq, and effective dose per intake, Sv/Bq
1-year-old, absorbed
dose to thyroid per
intake1-year-old,
effective dose per
intakeFetus 35 weeks,absorbed dose tothyroid permaternal intake

Fetus 35 weeks,
effective dose permaternal intake

Western pattern diet

1.9E-07

1.2E-08

1.3E-07

7.2E-09

Typical

9.5E-08

7.8E-09

3.4E-08

2.4E-09

Kelp-rich diet

3.3E-08

5.3E-09

Table A-4.31. Japan-specific indicative dose coefficients for ingestion of 132Te by adult membersof the public with the typical level of dietary intake of stable iodine: organ absorbed dose per
intake, Gy/Bq

TypicalAdult male,absorbed
dose to redbonemarrow per
intakeAdultfemale,absorbed
dose to redbonemarrow per
intakeAdult male,absorbed
dose tocolon perintakeAdultfemale,absorbed
dose tocolon perintakeAdult male,absorbed
dose tobreast per
intakeAdultfemale,absorbed
dose tobreast per
intake4.2E-10

5.9E-103.0E-09

3.6E-09

2.1E-10

1.6E-10

Table A-4.32. Japan-specific indicative dose coefficients for ingestion of 132Te by children withthe typical level of dietary intake of stable iodine: organ absorbed dose per intake, Gy/Bq

TypicalII.

10-year-old,absorbed
dose to redbone marrow
per intake

10-year-old,absorbed
dose to colon
per intake

10-year-old,absorbed
dose to breast
per intake

1-year-old,absorbed
dose to redbone marrow
per intake

1-year-old,absorbed
dose to colon
per intake

1-year-old,absorbed
dose to breast
per intake

6.7E-10

5.3E-09

2.8E-10

1.7E-09

1.0E-08

7.4E-10

JAPAN-SPECIFIC OCCUPANCY FACTORS

1.
This review is largely concerned with information on occupancy factors (i.e., thefractions of time spent outdoors and indoors) published since 2013 by Japanese authors in peerreviewed journals. It first summarizes the annual occupancy factors used in the UNSCEAR 2013
Report [UNSCEAR, 2014]; these were for four age-social groups of Japanese people and were
derived from Japanese official demography sources. It then summarizes the findings of six
publications that quantify the fractions of time spent indoors and outdoors by different groups ofadults and children in the Japanese population. Based on an analysis of the data in thesepublications, occupancy factors were derived for use in the update of the assessment of doses
made in the UNSCEAR 2013 Report.
A.

UNSCEAR 2013 Report – occupancy factors for Japan 1

2.
For this study of Japanese populations with their unique national cultural tradition, theoccupation factors pij were derived as fractions of daily time from the national survey data
specific for Japan [MIC, 2011]. The results are presented in table A-4.33.

1

Taken from section II.B.3 of attachment C-12 [UNSCEAR, 2014].

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

15

Table A-4.33. Set of annual occupancy factors pij for Japan used in the UNSCEAR 2013 Report
Occupancy factor, pij (dimensionless)Type of location
1-year-old

10-year-old

Outdoor worker

Indoor worker or
pensioner

Indoors

0.80

0.85

0.70

0.90

Outdoors including:

0.20

0.15

0.30

0.10

Paved surfaces

0.10

0.05

0.20

0.05

Unpaved surfaces

0.10

0.10

0.10

0.05

3.
The occupancy factors presented in table A-4.33, in combination with location factors(i.e., to take account of shielding effects while inside buildings, etc.), were used in [UNSCEAR,
2014] to characterize 12 social/age groups and dwelling house types. At the time when the
UNSCEAR 2013 Report was being prepared, only limited information on time spent by various
groups of the Japanese population in various locations had been published. The national survey
data used for this purpose did not contain explicit information on the fractions of time spent bypeople indoors and outdoors; occupancy factors in table A-4.33 had, therefore, to be assessedindirectly.
B.

Review of publications by Japanese authors since 2013 relevant for
the assessment of occupancy factors

4.
Takahara et al. [Takahara et al., 2014b] provided quantitative information on external
doses to evacuees. Doses were estimated for indoor workers, outdoor workers, and pensionerson the assumption that they lived in urban areas. It was assumed that indoor workers andpensioners spent all day in areas paved with asphalt. However, it was assumed that outdoor
workers spent their working hours in areas classified as “dirt surfaces” in an urban environment.
5.
In the survey, time spent indoors and outdoors for the three population groups wasmeasured: indoor workers, outdoor workers, and pensioners. The indoor workers surveyed werefrom the Fukushima City offices and the outdoor workers were from the Northern Fukushima
Affiliate of Contractors Association and Japan Agricultural Cooperatives. Data surveyed for themonths of February, March and April 2012 were used in deriving occupancy factors for use in
the update of the UNSCEAR 2013 Report [UNSCEAR, 2014].
6.
Some quantitative information on time spent indoors and outdoors by adult people
engaged in various activities, including statistical parameters that determined the probability
distribution functions of time spent outdoors by each population group under consideration, wasderived from table 18.3 of Takahara et al. [Takahara et al., 2014a] and included in table A-4.34
below. A limitation of this study was the absence of information on the numbers of peopleinterviewed.
7.
Takahara et al. [Takahara et al., 2014a] reported on the development of a probabilistic
model for dose assessment based on measurements conducted in early 2012. They studied doses
to residents of Fukushima Prefecture from external exposure by measuring ambient dose rates
and monthly doses to 500 individuals, as well as behaviour patterns of various population groups,
including indoor and outdoor workers, and pensioners.
8.
Participants were interviewed in February, March and April 2012. Participants from allgroups spent most of their time inside their homes. Those from the Senior Citizens’ Club stayed
inside their homes for 21 hours daily, amounting to about 90% of time in a day. The participants

16

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

from the three other groups (Fukushima City office workers, the Northern Fukushima Affiliate
of Contractors Association, and the Japan Agricultural Cooperatives) stayed inside their homes
for about 14–17 hours daily. The daily time spent outside houses was 1.2 hours for the Senior
Citizens’ Club and 2.2 hours for members of the Japan Agricultural Cooperatives. The
participants from Fukushima City office spent 0.2 hours outside their homes, and those from theContractors’ Association spent 0.3 hours outside their homes.
9.
A different trend between the population groups was observed with respect to time spent
in workplaces. The participants from the Fukushima City office stayed inside office buildings
on average for 7.0 hours per day while at work and outside of office buildings for only 0.1 hours.
The participants from the Contractors’ Association stayed inside buildings for 2.3 hours on
average and outside for about 6.2 hours. The participants from the Agricultural Cooperatives
stayed outside the house 2.2 hours and spent most of their working hours outside buildings,
staying inside for 0.3 hours and outside for 2.4 hours.
10.
Clear differences were found between the groups in terms of time spent outdoors andhow it varied between individuals. For participants from the Fukushima City office and the
Senior Citizens’ Club, normality was examined for the logarithmic values of time spent outdoors;significance levels were more than 5% for both groups. When the time spent outdoors daily was
expressed as a geometric mean for each month between February and April, it ranged from
0.4–0.8 hours for workers in the Fukushima City office and 1.0–1.7 hours for members of the
Senior Citizens’ Club. Arithmetic means of the daily time spent outdoors were in the range of
0.7–1.0 hours for those from the Fukushima City office and 1.7–2.6 hours for those from the
Senior Citizens’ Club.
11.
When time spent daily outdoors was expressed as the arithmetic means for each month
between February and April, it was in the range of 7.5–7.6 hours for those from the Contractors’
Association and 5.2–7.9 hours for those from the Agricultural Cooperatives.
12.
Estimates of the time spent indoors and outdoors by adults engaged in various activities
have been derived from Takahara et al. [Takahara et al., 2014a] and are presented in table A-4.34.
13.
Yajima et al. [Yajima et al., 2015] measured ambient dose rates at many residential andoccupational locations throughout a number of study areas in Fukushima Prefecture and also
individual doses with personal dosimeters. They also presented data on national occupancy of,and shielding by, buildings. For all locations investigated, the estimated effective dose to outdoor
workers was higher than that to indoor workers [Yajima et al., 2015].
14.
Individual doses were calculated for lifestyles of the following occupations: farmer,
forest worker, office worker, school staff, and home-based individuals (i.e., those who spent
most of the day at home). Time allocations for each place of residence or work were created foreach occupation by referring to statistical data on Japanese lifestyles [NHK, 2011].
15.
From this paper based on recent Japanese demography statistics (see above), it follows,inter alia, that office workers and school staff spend 15.4 hours at home, 7.3 hours in indoor
spaces and 1.3 hours outdoors. The latter is one half of the value used in the UNSCEAR 2013
Report (see attachment C-12 in the UNSCEAR 2013 Report [UNSCEAR, 2014]).
16.
Nomura et al. [Nomura et al., 2016] analysed the dependence of radiation dose on
patterns of behaviour of school children of various grades at a school in Minamisoma City.
Information on behaviour was obtained through interviews in autumn 2012 and included timespent in commuting to school and time spent outdoors after school and at weekends [Nomura et

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

17

al., 2016]. The Committee has estimated average times spent by schoolchildren in various
activities based on the results and these are summarized in table A-4.34.
17.
This study was based on the post-accident poll of school children in an affectedmunicipality of Fukushima Prefecture and its outcome may, therefore, have been influenced byadvice on safety and behaviour following the accident.
18.
Ishikawa et al. [Ishikawa et al., 2016] assessed time spent outdoors for residents of Iitate
Village from information collected in the Basic Survey conducted by Fukushima Medical
University in Fukushima Prefecture [Ishikawa et al., 2015]. From 3,400 responses to thequestionnaire, the authors randomly selected a total of 240 in accordance with the distribution of
the original population by age group, and estimated the average time spent outdoors per day. The
arithmetic mean for the 170 individuals for whom there was a full four months of data was
2.08 hours (95% CI: 1.64–2.51 hours). This is a much smaller value than commonly assumed inmany dose assessments, although a value of 2.4 hours had been adopted for indoor workers in
the UNSCEAR 2013 Report [UNSCEAR, 2014].
19.
Iitate Village is one of the municipalities most affected by the accident at FDNPS in
Fukushima Prefecture and it is likely that the behaviour of residents was influenced by safetyadvice. Whereas average time spent outdoors was 2.1 hours during the first 4 months after theaccident (95% CI: 1.93–2.10 hours with a range of 0–15.5 hours), the median was 0.94 hours.
These data can hardly be used for external model validation because the paper does not containany information about people’s occupancy.
20.
Mori et al. [Mori et al., 2017] assessed annual effective doses of indoor workers, outdoor
workers, and pensioners in Fukushima Prefecture taking account of variability in behavioural
patterns and 137Cs surface-activity levels. Behavioural patterns were obtained from surveys of
inhabitants of Fukushima Prefecture (10 people from the Fukushima City office, 8 people fromthe Building Contractors’ Society, 24 people from the Japan Agricultural Cooperatives, and25 people from a Senior Citizens’ Club). Averages and standard deviations for the time periods
spent indoors and outdoors by the respective groups were estimated by the authors and aresummarized in table A-4.34.
21.
Tsubokura et al. [Tsubokura et al., 2018] estimated doses from external exposure in
Minamisoma City and compared them with doses for three other cities in other prefectures. In
these four cities, external dose was measured every hour for two weeks using an individual
electronic dosimeter D-shuttle. The locations of participants were recorded every hour forcomparison with doses from external exposure. The time spent at home and in the workplaceaccounted for most of the time and was also the major contributor to the total dose from external
exposure.
22.
The measurements were made of city employees in four municipalities in Japan(Fukuyama City in Hiroshima Prefecture, Minamisoma City in Fukushima Prefecture, Nanto
City in Toyama Prefecture and Tajimi City in Aichi Prefecture). Twenty-five city employees
participated in the study from each municipality and the total number of employees measured
was 100. The measurements were made over a two-week period, from 29 May to 11 June 2017.
23.
Each employee recorded their activities every 30 minutes in a questionnaire under one offive categories: home, workplace, inside the city other than at home or work, during transit toand from work, and outside the city.

18

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

24.
The proportion of time spent in each category over the two-week period differed slightly
with municipality (chi-squared p<0.001). While there were differences between municipalities,
time spent at home and in the workplace (57% and 24%, respectively) accounted for most of thetime in all four municipalities. Doses received in the workplace and at home were the major
contributors to the overall exposures in all four municipalities.
C.

Discussion

25.
Although the published studies of human behaviour, based on interview and selfrecording, are limited both in number and scope, useful data can be extracted from them in termsof the average time spent daily (hours) by five groups of Japanese people (indoor workers,
outdoor workers, pensioners, 10-year-old children and 1-year-old infants) in various types oflocation. These are summarized in table A-4.34.
Table A-4.34. Average timea (in hours) spent per day by different groups of the Japanese
population in various types of location
Reference

Indoorhome

Indoorwork, etc.

Outdoors

Other

Comments

Adult indoor worker[UNSCEAR, 2014]

21.6[Takahara et al., 2014b]

2.4

Deterministic estimate fromJapanese official
demography sources

1.2 ± 2.1
[0.57 ± 3.3]

Fukushima City office
workers. Number
interviewed not specified
60 Fukushima City office
workers[Takahara et al., 2014a]

15.1

8.0

0.9

[Yajima et al., 2015]

15.4

7.3

0.5

[Mori et al., 2017][Tsubokura et al., 2018][MIC, 2011]

Values used in deriving
occupancy factors(see table A-4.35)

6.3 ± 2.5
[5.9 ± 1.5]
13.7

7.3

1.1

15.8–20.6

1.9–6.5

1.4–1.7

15

7

1

0.8
(commuting)

Office workers and schoolstaff, NHK ResearchInstitute

1.3 ± 1.0

10 Fukushima City office
workers

1.8 (in transit)

100 city officer workers infour cities
Deterministic range
estimated from Japanese
official demographysources1 (commuting)

Adult outdoor worker[UNSCEAR, 2014]

16.8[Takahara et al., 2014b][Takahara et al., 2014a]

15.2

2.2

7.2

Deterministic estimate fromJapanese official
demography sources

7.0 ± 2.9

Contractors Association
and Japan Agricultural
Cooperatives. Number
interviewed not specified

6.6

53 members of Contractors
Association and
60 members of Japan
Agricultural Cooperatives

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

Reference[Yajima et al., 2015]19

Indoorhome

Indoorwork, etc.

Outdoors

Other

Comments

17.5

0

6.3

0.2
(commuting)

Farmer and forest worker
NHK, Research Institute[Mori et al., 2017]

7.3 ± 5.6

8 people from the Building
Contractors’ Society,24 people from the Japan
Agricultural Cooperatives
Deterministic range
estimated from Japanese
official demographysources[MIC, 2011] as analysed
by S. Kinase

14.4–17.8

0.2

6.0–9.4

Values used in deriving
occupancy factors(see table A-4.35)

16

1

7

0

Pensioner[UNSCEAR, 2014]

21.6

2.4

[Takahara et al., 2014b]

2.7±4.9[1.3 ± 3.4]

Number interviewed not
specified
65 senior citizens from
Fukushima City

[Takahara et al., 2014a]

20.9

1.3

1.8

[Yajima et al., 2015]

22.9

0

1.1

[Mori et al., 2017][MIC, 2011]

Values used in deriving
occupancy factors(see table A-4.35)

22.3–22.6

22Deterministic estimate fromJapanese official
demography sources0Home-based individuals,
NHK Research Institute

1.9 ± 2.2

25 people from a Senior
Citizens’ Club

1.4–1.7

0.5

1.5

Deterministic estimate fromJapanese official
demography sources
010-year-old[UNSCEAR, 2014]

14.4

6.0

3.6

⁓1

[Nomura et al., 2016][MIC, 2011]

17.5

4.8

1.7

Values used in deriving
occupancy factors(see table A-4.35)

16

5.5

2

Deterministic estimate fromJapanese official
demography sources⁓0.5(commuting)Students of primary andsecondary school in
Minamisoma City, 2012
Deterministic range
estimated from Japanese
official demographysources⁓0.5(commuting)

20

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA

Reference

Indoorhome

Indoorwork, etc.

Outdoors

Other

Comments

1-year-old[UNSCEAR, 2014]

14.4

4.8

4.8

Deterministic estimate fromJapanese official
demography sources[MIC, 2011]

17.5

4.8

1.7

Deterministic range
estimated from Japanese
official demographysourcesValues used in deriving
occupancy factors(see table A-4.35)

17

5

2

a

Times (in hours) given in the table are arithmetic means ± standard deviation apart from those in [square parenthesis] which are geometricmean values and geometric standard deviations.

26.
The data, presented in table A-4.34 are mostly applicable to Fukushima Prefecture anddo not contradict national statistical data available at the following reference [SBJ, 2020].
Unfortunately, data presented by the Statistics Bureau of Japan does not contain explicit valuesof time duration spent by various groups of people indoors and outdoors. However, those could
be estimated indirectly from the data presented.
27.
The data in table A-4.34 on the amounts of time spent daily indoors and outdoors whileat home and work have been converted to dimensionless occupancy factors, pij by dividing by
24 hours and rounding to one significant figure. The resulting occupancy factors are presented
in table A-4.35 and they are the values the Committee has used in updating its assessment ofdoses in the UNSCEAR 2013 Report [UNSCEAR, 2014].
28.
There are differences for some of the population groups in the amounts of time assumed
to be spent outdoors compared with what was assumed in the UNSCEAR 2013 Report[UNSCEAR, 2014]. For outdoor workers, indoor workers and pensioners, the differences areeither non-existent or not significant; however, for children, the time spent outdoors assumed in
the UNSCEAR 2013 Report was a factor of about two greater than that indicated in table A-4.35.
Table A-4.35. Occupancy factors derived from data in table A-4.34
Occupancy factor, pij (dimensionless)
Location
1-year-old

10-year-old

OutdoorworkerIndoor worker

Pensionera

Indoors including:

0.9

0.9

0.7

0.9

0.9

At home and others

0.7

0.7

0.7

0.6

0.9

At work, school, kindergarten, etc.

0.2

0.2

Outdoors including:

0.1

0.1

0.3

0.1

0.1

Areas with paved surfaces

0.1

0.1

0.2

0.1

0.1

Areas with unpaved surfacesaOccupancy factors for pensioners are broadly comparable with those for indoor workers.

0.3

0.1

ANNEX B, ATTACHMENT A-4: JAPAN-SPECIFIC DATA21

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