福島県立医科大学 学術機関リポジトリ

Title

Estimation of the Early Cs-137 Intake of Evacuees from Areas
Affected by the 2011 Fukushima Daiichi Nuclear Power Plant
Accident Based on Personal Behavioral Data and the Latest
Atmospheric Transport and Dispersion Model Simulation

Author(s)Kim, Eunjoo; Igarashi, Yu; Hashimoto, Shozo; Tani, Kotaro;
Ishikawa, Tetsuo; Kowatari, Munehiko; Kurihara, Osamu

Citation

Health physics. 121(2): 133-149

Issue Date

2021-08

URL

http://ir.fmu.ac.jp/dspace/handle/123456789/1867

Rights© 2021 Health Physics Society. This is a non-final version ofan article published in final form in "Health Phys. 2021
Aug;121(2):133-149".

DOI

10.1097/HP.0000000000001429

Text Version author

This document is downloaded at: 2024-10-10T22:54:56Z

Fukushima Medical University

Final Manuscript (Abstract, Text, References, Footnotes, List of
Figure Captions)

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ESTIMATION OF THE EARLY 137CS INTAKE OF EVACUEES FROM AREAS
AFFECTED BY THE 2011 FUKUSHIMA DAIICHI NUCLEAR POWER PLANT
ACCIDENT BASED ON PERSONAL BEHAVIORAL DATA AND THE LATEST
ATMOSPHERIC TRANSPORT AND DISPERSION MODEL SIMULATION

Eunjoo Kim,* Yu Igarashi,*,† Shozo Hashimoto,* Kotaro Tani,*
Tetsuo Ishikawa,§ Munehiko Kowatari,* and Osamu Kurihara**National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa,Inage-ku, Chiba-city, Chiba, Japan†The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-city, Chiba, Japan§

Fukushima Medical University, 1-Hikarigaoka, Fukushima-city, Fukushima, JapanThe authors declare no conflicts of interest.

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Corresponding author: Dr. Osamu Kurihara, Department of Radiation Measurement and2

Dose Assessment, Center for Advanced Radiation Emergency Medicine, Quantum Medical

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Science Directorate, National Institutes for Quantum and Radiological Science and Technology,

44-9-1 Anagawa, Inage-ku, Chiba-city, Chiba 263-8555, Japan.

56Tel.: +81-43-206-4734, Fax: +81-43-284-1769. Email: kurihara.osamu@qst.go.jp

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ABSTRACT

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More than nine years have passed since the 2011 nuclear disaster in Fukushima Prefecture,

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Japan. During this period, much effort has been made on the dose reconstruction for Fukushima

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residents; however, the estimation of the internal dose due to the potential intake of the short-5

lived radionuclides (mainly, 131I) has been challenging because of the lack of direct human6

measurements at the early phase of the accident. Our previous study revealed that the residual

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cesium body contents observed in delayed whole-body counter (WBC) measurements of

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residents from Namie-town, one of the most affected municipalities), varied greatly with the9timepoint of their evacuations on 12 March 2011 when the first explosive event occurred at the10

accident site; i.e., the late evacuees had much higher residual Cs body contents compared to the11

prompt evacuees. The present study thus aimed to clarify this finding by reproducing the12

exposure situation based on the evacuees' personal behavioral data in combination with the13latest atmospheric transport and dispersion model (ATDM) simulation for 356 selected subjects

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in adult and 15-year (13–17 yrs) age groups. The results demonstrated that the ATDM

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simulation-based method could reasonably reproduce the subjects' exposure situation,

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supporting the previous finding. However, the residual 137Cs body contents calculated by this17

method were only 10%–20% of those in the subjects' WBC measurements. This large

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discrepancy was considered to be caused by both the present method's underestimation and the19overestimation of the subjects' early intake in the WBC measurements due to a conservative20

intake scenario not assuming potential additional intake. Additional studies are needed to21further clarify the reasons for the discrepancy and to evaluate the magnitude of the inhalation

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dose in the accident.

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Key words: Fukushima; early internal dose; 137Cs; ATDM

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INTRODUCTION

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More than nine years have passed since the Tokyo Electric Power Company's (TEPCO's)

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Fukushima Daiichi Nuclear Power Plant (FDNPP) accident that was triggered by the Great East

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Japan Earthquake and subsequent massive tsunami on 11 March 2011. During this period, much5effort has been made to determine the dose assessment of the residents of Fukushima Prefecture

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regarding their additional radiation exposure from the accident (Ishikawa 2017). The results of7

the research during this 9-year period indicated that the estimated radiation doses to the8residents were to be low in general, and the residents' future radiation-induced risk was

9considered low (UNSCEAR 2014). However, as we have pointed out (Kim et al. 2016a and c;

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Kim et al. 2020; Kim and Kurihara 2020), further studies are still needed to improve the dose

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assessment — in particular, the dose assessment for internal thyroid exposure from the short-

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lived radionuclides (e.g., 131I, 132Te-132I, and 133I). The greatest obstacle has been the shortage

13of direct human measurements at the early phase when the traces of 131I, the main contributor

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to the internal thyroid dose), were detectable. For this purpose, the early phase after the FDNPP

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accident could be considered the period from the 11 March until the end of March or early April

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2011 at the latest.

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To address the problem of the lack of early phase direct human measurements, we proposed18

a method that uses the results of direct human measurements taken with whole-body counters

19(WBCs) by Japan's National Institute of Radiological Sciences (NIRS, reorganized in 2016 as

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the National Institutes of Quantum and Radiological Science and Technology, QST) and the21

Japan Atomic Energy Agency (JAEA) (Kim et al. 2016a and b; Kurihara et al. 2018). Although22

the target radionuclides of these measurements were limited to 134Cs and 137Cs only, we derived

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the intake ratio of 131I to Cs at the early phase from the results of two independent direct

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measurements (to assess the thyroid dose for children and the whole-body dose for adults), and25

used this ratio to estimate the internal thyroid dose. However, one critical question later arose

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regarding this method, namely whether the Cs detected in the WBC measurements that were
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performed several months after the accident or later reflect the trace of the early intake or not.

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In the Cs biokinetic model proposed by the International Commission on Radiological3

Protection (ICRP 1989), the biological half-lives for Cs in the systemic body for adults, 10

4year(-yr)-olds, and 5-yr-olds were assumed to be 110, 50, and 30 days, respectively. We

5attempted to solve this question by conducting analyses of the WBC and personal behavioral

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data of residents who were living near the FDNPP at the time of the nuclear accident. The results

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revealed a distinct difference in the residual Cs body contents among individuals depending on

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the timepoint of their evacuation, which strongly indicates a causal relationship with the

9hydrogen explosion event at the FDNPP's Reactor Unit 1 building on the afternoon of the day

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following the FDNPP accident (at 15:36 Japanese Standard Time [JST] on 12 March 2011). In

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other words, it was revealed that the Cs intake was much higher in the late evacuees compared12

to the prompt evacuees from Namie-town, which is approximately 7-8km from the FDNPP

13(Igarashi et al. 2020). We divided the residents into prompt- and late-evacuee groups of14

residents depending on their whereabouts at 15:00 on 12 March 2011 (as described later). Our

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analyses revealed that the Cs detection rates (and the 90th percentile values of the estimated

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137

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(5.4  103 Bq) and 60% (1.6  104 Bq), respectively. Approximately 20% of the individuals

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analyzed were categorized as late evacuees. Here, the 137Cs intake of each individual was

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calculated based on the residual 137Cs whole-body contents detected in the WBC measurements

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in combination with the intake scenario of acute inhalation on the possibly earliest intake day

21(i.e., 12 March 2011), which is the most conservative intake scenario.

Cs intakes of individuals) of the prompt and late evacuees were approximately 20%

22This finding is of great importance in terms of determining the true and precise exposure

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situations of residents living in the areas adjacent to the FDNPP where evacuation was ordered

24(NAIIC, 2012). We thus attempted to clarify these residents' exposures by making use of the25latest atmospheric transport and dispersion model (ATDM) simulation published in 2020 and

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we discuss the feasibility of this simulation as a tool for estimating the early internal dose to the
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residents involved in the accident.

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MATERIALS AND METHODS

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Subjects analyzed in the present study

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The subjects examined in the present study were the same as those analyzed in our Igarashi

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et al. (2020) study, i.e., residents from Namie-town, one of the municipalities most severely

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affected by the FDNPP (shown in Fig. 1). However, the present subjects were limited to two

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age groups: the Adults group (aged ≥18 years) and the 15-yr group (ages 13–17 yrs) who moved

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toward Tsushima district of Namie-town or Minamisoma-city shortly after the accident and10spent time there (>24 hr) during the period between 0:00 on 12 March and 0:00 on 14 March.

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Here, the ages of the subjects are those as of the time of the accident (on 11 March 2011). In

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our present and previous studies, Tsushima district of Namie-town is defined as an area outside13

the 20-km radius of the FDNPP. The subjects underwent WBC measurements at the JAEA

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during the months from July to December in 2011 (mostly July and August). The minimum

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detectable activity (MDA) of these WBC measurements for 134Cs and 137Cs were both

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approximately 300 Bq per body (Kurihara et al. 2018). The two age groups were further

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subdivided into prompt and late evacuation groups: the former was the residents who had

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moved outside the FDNPP's 20-km radius as of 15:00 on 12 March, and the latter residents had

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not done so. The numbers of the four groups were as follows: prompt evacuees moving toward

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Tsushima: G1(T) (n=231), late evacuees moving toward Tsushima: G2(T) (n=37), prompt

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evacuees moving toward Minamisoma: G1(M) (n=64), and late evacuees moving toward

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Minamisoma: G2(M) (n=24). The number of the subjects analyzed in this study thus totaled

23356. The data of the committed effective doses (CEDs) to these four groups from 134Cs and

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137

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Igarashi et al. (2020) study. Briefly, the behavioral data of the subjects contains the history of

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their whereabouts (i.e., the place name and its latitude and longitude), the time spent

Cs were as seen in Table 1. Details of the subjects' behavioral data are described in our

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indoors/outdoors or moving, and the type of building where the person stayed (e.g., a wooden

2house or concrete building). The behavioral data were provided hourly until 25 March and daily

3from 26 March to 11 July (only for representative places to stay and commute to/from); however,4

the data for April and later months were missing for most of the subjects. Additional

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information to the above is that the behavioral data provided only landmark places in the6prefecture of destination (e.g., a prefectural government office) when the person stayed or

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moved outside Fukushima Prefecture. The locations of individuals during moving were

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determined assuming a uniform linear motion between the places of departure and destination

9in the same manner as our previous study (Igarashi et al. 2020). The use of the behavioral and10

whole-body data in the present study was approved by the Research Ethics Committees of the11

authors' institutes (QST-NIRS: No. 13-011, Fukushima Medical University: No. 1892).

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ATDM simulation and calculation of residual 137Cs whole-body contents

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We used the latest ATDM simulation provided by Worldwide version of System for

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Prediction of Environmental Emergency Dose Information (WSPEEDI) ver. 2 (Terada et al.

162020). WSPEEDI-II has been used to understand the behaviors of the radionuclides released

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into the environment in the FDNPP accident (Terada et al. 2012; Kobayashi et al. 2013; Katata18

et al. 2015; Chino et al. 2016). The local-scale version system (SPEEDI, which is used in19

emergency situations at nuclear power plants in Japan) was developed and updated to perform20

immediate ATDM simulations using real-time metrological data and a given source term (e.g.,21

the information on the release rate of radionuclides) that is to be obtained from a stack monitor

22(Chino 1986; Chino and Adachi 2003; Suda 2006). However, the real-time information on the23

source term could not be obtained in the case of the FDNPP accident. The source term was thus

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estimated by means of inverse calculations to reproduce observed monitoring data such as the25

ambient dose rate and the ground deposition density. The latest simulation by Terada et al.

26(2020) has been improved by using an optimized method based on Bayesian interference that
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incorporated the newly published hourly 137Cs air concentration dataset obtained from2

suspended particulate matter (SPM) samples collected at air pollution monitoring stations.

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Details of the analysis of SPM samples have been described elsewhere (Oura et al. 2015, 2020;

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Tsuruta et al. 2014, 2018).

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In the present study, we dealt with the intake via inhalation of 137Cs during the early phase6of the accident only. 134Cs was excluded from the present analyses in this study because the7

WBC results for 134Cs were similar to those of 137Cs (Igarashi et al. 2020). The 137Cs intake

8amount was then calculated by using the following equation:

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𝐼 = ∑𝑗 𝐴𝑗 ∙ 𝑉 ∙ 𝐷𝑅𝐹𝑗 ∙ ∆𝑇

(1)

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where I is the intake amount of 137Cs (Bq), Aj is the 137Cs air concentration at the nearest grid13cell in a computational domain of WSPEEDI-II from the place where the subject stayed at the

14time j (Bq m−3), V is the hourly ventilation volume (m3 hr−1), DRF is the dose reduction factor

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due to staying indoors (dimensionless), and ΔT is the time span of the database generated from16

simulations by WSPEEDI-II (1 hr). This database contains a dataset of the horizontal two-17

dimensional (2D) distribution of the 137Cs air concentration (averaged hourly) at the ground18

level for the time period between 01:00 on 12 March and 00:00 on 1 April, 2011 (480 [= 24  20

19days] outputs in total). The dataset used for dose calculations in this study was obtained from a

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regional-scaled ATDM simulation by WSPEEDI-II (570  570 km2 with 3-km resolution); we

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also used a local-scaled ATDM simulation (190  190 km2 with 1-km resolution) for a detailed

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visualization of the 137Cs air concentration (described below). The time integration in Equation

23(1) was performed up to the end of March or 25 March 2011 depending on the analyses. The

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value of the hourly ventilation volume was set at 0.925 m3 h−1 (22.2 m3 per day) for Adults and25

0.838 m3 h−1 (20.1 m3 per day) for the 15-yr groups in reference to the ICRP publication 71

26(1995). The DRF was set at 0.5 when the subject stayed indoors (described later), and at 1.0
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when the subject stayed outdoors or was moving.

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The residual 137Cs body contents of a given subject, which were to be compared with the3results of the subject's whole-body measurements, were calculated using the following

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equation:5

𝑀 = ∑𝑘 𝐼𝑘 ∙ 𝑅(𝑇𝑀 − 𝑇𝑘 )

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(2)

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where Ik is the 137Cs intake amount (Bq) on the day Tk, and R(TM −Tk) is the 137Cs retention rate

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(Bq per Bq intake, dimensionless) for the whole-body as a function of the elapsed days from Tk

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to the measurement day, TM. The data of R(t) for the Adults and 15-yr groups were taken from11

the MONDAL system developed by NIRS (Ishigure et al. 2004). Here R(t) was calculated using

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the default parameters set to assess the public exposure by inhalation: 1 m in an activity

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median aerodynamic diameter (AMAD) and Type F (fast absorption) for inhaled particulate

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aerosols (ICRP 1995). The time integration in Equation (2) was performed up to the end of

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March 2011, as in Equation (1). The data manipulation and visualization (e.g., the locations of

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individuals and the horizontal 2D distribution of the 137Cs air concentration on maps) were

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implemented using programs written in Python by the authors.

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Residents' evacuation

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For a later discussion, the information on the residents' evacuation is provided next.

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According to the records published by Namie-town (2018) and another relevant report

22(Zengenkyo, 2012), the town decided to evacuate residents on a voluntary basis, based on

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information from television reports. TEPCO was supposed to report the plant's situation to24

Namie-town without delay based on a mutual agreement between the contractor and the town

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in cases of emergency, but they could not. The Japanese central government issued evacuation

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orders to municipalities adjacent to the FDNPP and adjacent to another facility, the Fukushima
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Daini Nuclear Power Plant (located ~12 km south of the FDNPP); however, these orders did

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not reach Namie-town directly (or via Fukushima Prefecture) due to communication failures.

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Shortly after the earthquake at 14:46 on 11 March, Namie-town announced an immediate4

evacuation order to residents living in its coastal area based on the forecast of a tsunami's arrival,

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and most of those residents then evacuated to the town office (located 7–8 km away from the

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FDNPP), the community center and many other shelters. The coastal area of the town was

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seriously damaged due to the earthquake and massive tsunami. Table 2 provides the time chart

8of countermeasures taken by Namie-town as well as the evacuation orders by the government.

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The residents' evacuation was performed in two main steps. In the first evacuation on 11 and

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12 March, residents moved to areas outside the 10-km radius and then outside the 20-km radius

11of the FDNPP by private vehicles and buses. The town office was also transferred to Tsushima

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district on that day. The evacuation took more than several hours (normally 30–40 min) due to13

a heavy traffic jam on Route 114. Note that the evacuation to areas outside the 20-km radius

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was made earlier than the evacuation order by the Japanese central government (at 18:25). In

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the second evacuation on 15 March, the residents moved further to Nihonmatsu-city (~50 km

16west of the FDNPP) or other municipalities (e.g., Fukushima-city, Koriyama-city, and others).

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Akahane et al. (2013) considered 18 representative evacuation scenarios to perform the18

preliminary external dose estimation for residents of Fukushima Prefecture; two of the 18

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scenarios (Scenario 7 and Scenario 13) were for Namie-town residents (Fig. 2). In our previous

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study we observed that some of the Namie-town residents moved toward Minamisoma-city,

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which was not included in the 18 scenarios. A subsequent mass evacuation was held on 5 April

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2011 or later. About 200 shelters were opened in various municipalities of Fukushima

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Prefecture to receive the residents.

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The numbers of Namie-town's residents who evacuated inside and outside Fukushima

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Prefecture were 14,184 and 7,216, respectively (unknown for 34 persons). No instructions were26

received from the local government or the prefecture about the distribution and administration
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of stable iodine (KI). Namie-town had a stockpile of 25,000 KI tablets; however, they did not2

use them.

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RESULTS

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Movement of the subjects and behavior of aerial 137Cs

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Figs. 3 and 4 illustrate the locations of individuals on the maps at several time points on 12

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and 15 March. The 137Cs air concentration at the ground level (created by the local-scaled

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ATDM simulation) is superimposed on the same maps at the same time points. The symbols in

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the figures denote each group described above; the blue symbols are the persons moving toward

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Tsushima district, i.e., G1(T) and G2(T), and the red symbols are the persons moving toward

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Minamisoma-city, i.e., G1(M) and G2(M). The same figures but at other time points and on

12other days are provided in Appendix A. As shown in the figures, the locations of the subjects

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become widely scattered with the increase in the distance from the FDNPP along with the14elapsed time. The locations of the subjects on 12 March (Fig. 3) indicates the crowded nature

15of the evacuation routes mentioned above.

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In the ATDM simulation, the release of 137Cs began in the morning on 12 March and then17

increased in the afternoon as a result of the hydrogen explosion at Reactor Unit 1. The aerial

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137

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locations of some subjects, in particular those staying close to the FDNPP or moving toward

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Minamisoma-city. On March 15 (when the largest release event was expected to occur), the21

aerial 137Cs flowed to the south in the morning, and its direction then turned clockwise in the22

afternoon, resulting in the generation of a high-radiation background area in the northwest due

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to wet deposition at night. As can be seen in the Figs. 3 and 4, many of the subjects appear to24

have been exposed to the aerial 137Cs at various places apart from the FDNPP on that day. Fig.

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5 presents the time series of the ratios of subjects in each group who stayed outside the 20-km

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radius of the FDNPP. As shown, the ratios were almost 1 (100%) for each group on 13 MarchCs that originated from this event flowed mainly to the north afterward and covered the

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and later; in other words, no apparent difference was found in the ratios among the four groups

2

except for those on 12 March.

3
4

137Cs inhalation intake of the subjects

5Fig. 6 presents the total 137Cs intake amounts (via inhalation up to 25 March) calculated

6

based on the ATDM simulation for each group in box-whisker plots; the two age groups are

7

also individually displayed. As shown in the figure, the 137Cs intake amounts are higher in the

8late-evacuation groups than in the prompt-evacuation groups: G1(T) < G2(T), and G1(M) <9

G2(M). The 137Cs intake amounts of the persons moving toward Minamisoma-city tend to be

10

higher than those moving toward Tsushima district: G1(T) < G1(M), and G2(T) < G2(M). The

11

ratio of the persons whose 137Cs intake amounts were >1,000 Bq was 17% of the subjects

12

analyzed in this study (356 persons in total), whereas the same ratio in the WBC measurements13

was 32%. Fig. 7 presents the relative daily 137Cs intake amounts for each group in bar charts as

14

100% of the total (up to 25 March). Each bar in the figure is the average of the subjects whose

15

total 137Cs intake amounts exceeded 500 Bq. One remarkable finding is the distinct difference

16

in the 137Cs intake on 12 March between the G1(T) and G2(T) groups; however, such a17

difference does not appear between the G1(M) and G2(M) groups. The contribution of the18

intake on 15 March is also unique to each group; for example, it is the highest in the G1(T)19

group, whereas is the lowest in the G2(M) group.

20
21

Comparison of the residual 137Cs body contents between the ATDM simulation and the22

WBC measurements

23

Fig. 8 presents the residual 137Cs body contents for each group in box-whisker plots; the left24

panel displays the results from the ATDM simulation using Equation (2) and the right panel

25

displays the results from the WBC measurements. Note that more than one-half of the G1(T)26

and G1(M) subjects’ values were below the MDA level in the WBC measurements. As seen in
11

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the figure, the residual 137Cs body contents calculated based on the ATDM simulation were2

considerably lower than the result of the WBC measurements; note that the scale of the vertical

3

axis is different between the left and right panels in the figure. In the ATDM simulation, the4body contents of only eight individuals exceeded 300 Bq (corresponding to the MDA) of the5

WBC measurements. The ratios of the two methods (ATDM/WBC) were roughly 0.1–0.2 at the675th and 90th percentiles.

7
8

DISCUSSION

9

As described in the Introduction, the reconstruction of the early internal dose to residents in

10

the FDNPP accident has been challenging because of the shortage of direct human11

measurements for 131I. The total of those measurements was only approximately 1,300, and the12measurements were gathered from relevant publications (Tokonami et al. 2012; Matsuda et al.

13

2013; Kim et al. 2020). To solve this problem, we have attempted to apply ATDM simulations

14

to the estimation of the internal thyroid doses due to the inhalation of 131I as a supplementary15

method (Kim et al. 2016a and d). Other researchers have used ATDM simulations for a similar

16

purpose. Kawai et al. (2018) and Miyatake et al. (2020) attempted to reconstruct a time-series

17

profile of the 131I concentration in tap water available in the areas of concern after the FDNPP

18

accident with the help of ATDM simulations by WSPEEDI-II to estimate the ingestion dose.

19

Ohba et al. (2020) and Takagi et al. (2020) estimated the internal thyroid doses due to the20

inhalation of 131I by using the latest ATDM simulations available. Our present study used the21same database generated by WSPEEDI-II as that used by Ohba et al. (2020); however, we had

22

a different focus, namely to confirm the validity of the application of ATDM simulations to23

future dose reconstructions for individuals by comparing the simulation results with the results

24of WBC measurements.

25

The critical finding of the present study is that the estimation based on the ATDM simulation

26

could not reproduce the residual 137Cs body contents from the WBC measurements of the
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subjects analyzed. The values of the ATDM simulation were only 0.1–0.2 times as large as

2

those of the WBC measurements. This large discrepancy should be examined from the3

perspective of at least two possibilities (assuming that there is no error in the WBC

4measurements); one is the intake by routes other than inhalation at the early phase, and the other5is the underestimation of the 137Cs air concentration computed by the ATDM simulation.

6

Regarding the first possibility, we note that a small amount of the daily intake due to7ingestion would increase the residual 137Cs body contents observed in the WBC measurements,

8

resulting in the overestimation of the Cs intake at the early phase due to the conservative intake

9

scenario used. In fact, several studies revealed that the dietary intake of 134/137Cs in Fukushima

10

Prefecture in the first year after the accident was expected to be a few Bq per day or occasionally11

more (Koizumi et al. 2012; Harada et al. 2013). Even such a small daily intake amount could

12

have a significant influence on the results of the WBC measurements if accumulated. For

13

example, the residual 137Cs body content increases up to ~100 Bq in the case of adults on the

14

150th day of chronic ingestion with a uniform intake of 1 Bq per day (Kurihara et al. 2018).

15

The incidental ingestion of contaminated soil can also be considered as a possible exposure

16

pathway (IRSN 2012). In terms of inhalation, the dust sampling at several locations within ~30

17

km of the FDNPP demonstrated value that were mostly below the detection limits in April or18

later (NRA 2011). On the other hand, the Cs air concentration at a parking lot in Fukushima-

19

city ranged fom 10 to 30 mBq m−3 during the period from September to December 201120

(Akimoto 2015), which was caused by the migration from the heavily contaminated areas

21

around the FDNPP or its resuspension from the ground. The Cs air concentration at this site

22

would be higher at the earlier time points (although the data are missing). Thus, the occasional

23

intake after the early phase could occur via both ingestion and inhalation. Such a possibility is

24

expected to exist evenly in all groups, because residents of Namie-town evacuated to various

25

places inside and outside Fukushima Prefecture (Namie-town, 2018). As a result, the26

differences among the groups in their early intake amount between the groups would become
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relatively small with time and disappear in subsequent WBC measurements if the additional2

intake was significant; however, this was not the case in our stud.

3

The relationship between the intake amount and the residual body content is determined4

depending on the period of time between the intake event and the measurement. In the case of5

the inhalation of 137Cs as a Type F compounds with an AMAD of 1 m, the whole-body

6

retention rates at the 150th days after intake for the Adult and 15-yr groups are 1.17  10−1 and7

9.15  10−2, respectively. The number of elapsed days from the first possible intake event (128March 2011) until the WBC measurements for the subjects analyzed in this study was 155 days

9(1 =23 days). Fig. 9 presents the 137Cs whole-body retention rate as a function of the number

10of elapsed days along with the number of WBC measurements taken on each day, suggesting

11

that the 137Cs residual body contents detectable in the WBC measurements were decreased to12

only around 10% of the initial intake amounts via inhalation. Note that about one-half of the13

intake amount is immediately removed by exhalation. In detail, the total deposition rate in the14

respiratory tract is 48.58% for the Adult group and 46.38% for the 15-yr group (ICRP 1995) in15

the case of inhaled particles with an AMAD of 1 m. Thereby, the WBC measurements should

16

have detected only the persons whose 137Cs intake amounts were >3,000 Bq at least (i.e., 10

17times as large as the MDA value) if there was no additional intake as described above. However,18

the 137Cs intake amounts calculated from the ATDM simulation were <3,000 Bq for almost all

19of the subjects (Fig. 6).

20

The actual physiochemical form of Cs-containing particles released from the FDNPP should

21

also be mentioned here because this can influence the above-described retention rate. Several

22

studies reported the measured aerosol sizes with AMAD values of 0.5‒1.5 m (Kaneyasu et al.

23

2012; Doi et al. 2013; Miyamoto et al. 2014). Taking into account the fact that the samples were24

collected in distant places (>100 km) from the FDNPP in those studies, the aerosols potentially25

inhaled by the present study’s subjects are expected to be larger. The 137Cs whole-body retention

26

rate for particulate aerosols with an AMAD of 5 m is approximately 40% larger than that for
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particulate aerosols with an AMAD of 1 m because of the increase in the particle deposition2

rate in the respiratory tract. A greater proportion of larger aerosols or submicron-sized aerosols

3would lower the deposition rate. The gaseous form of cesium was found to be minor compared4

to its particulate form (JAEA 2011). Regarding the absorption type, Type F would be a5reasonable assignment in light of the reported by Kaneyasu et al (2012) that soluble sulfate

6

aerosol was a potential transport media for Cs. By contrast, other studies revealed the existence

7of insoluble Cs particles released from the nuclear plant (Adachi et al. 2013; Igarashi et al.

82019), suggesting that Type S (slow absorption) would be an appropriate assignment instead.

9

However, the 137Cs whole-body retention rate is rather lower in Type S than in Type F until the10

200th-day post-intake due to a larger fraction of direct fecal excretion without absorption in the11gastro-intestine tract, which is parameterized as the f1 value in the dosimetric models (ICRP

121995): 1.0 for Type F and 0.01 for Type S. The assumption of Type S results in further

13

enhancing the underestimation of the residual 137Cs body contents. The insoluble Cs particles

14

found in the vicinity of the FDNPP were characterized into two types based mainly on the15

isotopic ratio of 134Cs/137Cs (Igarashi et al. 2019). One of the two types (Type B) has been

16

considered to originate from Reactor Unit 1, which had with a core inventory with a lower

17

134

18

fuel melt-down occurred. Type B particles found in soil had high radioactivity (~30–19,000 Bq

19

per particle) and large sizes (~40–400 m). These particles would have rarely contributed to20

inhalation because of their sizes. On the other hand, the trace of the plume passage from Unit 1

21

remained in the area at a length of about 15 km and a width of 3 km in the north-northwest

22(NNW) direction from the FDNPP (Kobayashi et al 2017). Chino et al (2016) also reported the23

direction of the same plume passage and reproduced it in their ATDM simulations. which were24

succeeded in the study by Terada et al (2020). The ATDM prediction in our present study would

25

thus capture the sequence of exposure to the radioactive plume by the subjects in the afternoon

26

on 12 March, although the detailed characteristics of released particles were not considered in

Cs/137Cs radioactivity ratio compared to those of Reactor Units 2 and 3, where the nuclear

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the ATDM simulation used herein.

2

Regarding the second possibility, we directly compared the ATDM simulation with SPM

3data in terms of the 137Cs air concentration at several locations. Fig. 10 illustrates the results of4

our comparison of the daily-integrated values of the 137Cs air concentrations at Haramachi (the5middle part of Minamisoma-city) and Fukushima-city. Table 3 provides the time-integrated

6

137

7

some subjects. From these results, although significant underestimations were found for8

Nihonmatsu-city and Fukushima-city with relatively low

9data, we consider that the ATDM simulation would be reasonably applied to the estimation of10

the inhalation doses to some of the subjects in the G1(M) and G2(M) groups (i.e., the11

individuals who moved toward Minamisoma-city shortly after the accident and then stayed

12

there for a while), whereas the ATDM simulation would be likely to underestimate the13inhalation doses to those who continued to stay in Fukushima-city or Nihonmatsu-city after the14

accident, which corresponds to some of the G1(T) and G2(T) subjects.

Cs air concentration values from 12 to 22 March at five locations on the evacuation routes of137

Cs air concentration in the SPM

15

The intake amount via inhalation could be estimated as long as the air concentration is

16

accurately reproduced from ATDM simulations. Although, to our knowledge, there has been

17

only one case study that examined the ratio of the 137Cs intake amount estimated from WBC

18

measurements to that calculated from air sampling in the FDNPP accident, the ratios for three

19

adult males staying in Ibaraki Prefecture (adjacent to Fukushima Prefecture in the south, Fig.

20

1) during the arrival of major radioactive plumes on 15 March and later were found to be

21

roughly 0.7 on average (Kurihara et al. 2016), which was considered reasonable taking into

22

account the dose reduction factor due to staying indoors. Note that the WBC measurements in23

this study were performed in a timely manner so that the number of occasions of incidental

24

ingestion was minimized.

25

From a different point of view, the results of the ATDM simulations presented herein may

26

indicate that the 137Cs inhalation intake at the early phase would have been very minor enough
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to be undetectable at the time of the WBC measurements. However, then what caused the2finding in our previous study, the distinct difference in the Cs internal dose between prompt and3late evacuees? One may doubt the possibility of intake from the body surface contamination by

4

unintentional habits (e.g., touching the face) at the early phase. A large number of residents

5were examined for body surface contamination during their evacuation, and it was revealed that6

there were some heavily contaminated individuals (Kondo et al. 2013). The intake would be

7

trivial for Cs because its radioactivity fraction in the contamination was found to be minor

8

compared to the short-lived radioiodines (Ohba et al. 2017). To address the above question, we

9need to further evaluate the possibility of an additional intake by Fukushima residents. The

10extremely-high residual Cs body contents (a few kBq or more) in late WBC measurements for11

some residents were likely to be due to an accidental ingestion of highly-contaminated food

12

(Tsubokura et al. 2014). This may be partly true in our study population.

13

On the other hand, interestingly, the distribution profiles of the residual 137Cs body contents

14

for each the present groups of subjects appear to be similar between the ATDM simulation and15

the WBC measurements, (many plots of the latter values are not shown, in particular for the16

prompt evacuees due to the existence of MDA) (Fig. 8). The magnitude relationship among the17four groups generally agreed with each other: G1(T) < G1(M) < G2(T) < G2(M) (Fig. 8). In

18

addition, the ATDM simulation results were consistent with our finding that 12 March was the19most influential day for late evacuees in terms of their possible internal exposure. One new20

insight from the latest ATDM simulation is that the inhalation dose of 131I was significantly

21

reduced in the areas around Tsushima district compared to that predicted by the previous ATDM

22

simulation (Kim et al. 2016d). It was also indicated that the inhalation dose in Minamisoma-

23

city would have been brought by the radioactive plumes arriving there several times (in24particular on 12–13 and 18–20 March). These results may be reflected in the WBC

25

measurements. The daily accumulated 137Cs air concentration at different locations on two

26

national roads (Routes 114 and 6) from the ATDM simulation are provided in Appendix B; Fig
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B1 and Table B1 demonstrate the locations at which the data were obtained, and Tables B2 and2B3 provide the data for the locations on Route 114 and Route 6, respectively. Route 6 was

3

expected to be used for residents who evacuated toward Minamisoma-city (Fig. 3), although it

4

was reported that the road was unavailable due to serious damage (Zengenkyo, 2012). Note that5

the 137Cs inhalation intake amount can be calculated by multiplying the values in Tables B2 and6

B3 by the hourly ventilation volume. These data indicate that the 137Cs inhalation intake is7higher in the north area than in the northwest, unlike the previous ATDM simulations. However,8

in either case, it is certain that the residents' evacuation would have considerably reduced the9inhalation dose that the resident would have received in the FDNPP's neighboring areas. In this10

regard, it would be notable that most of the residents completed evacuation outside the 20-km

11radius much earlier than the evacuation order by the Japanese central government at 18:25 on

12

12 March (Fig. 5).

13

The limitations of the method applied herein are as follows. First, the subjects' behavioral

14

data used in this study were created from answer sheets collected from residents for the purpose

15of estimating the individual external doses for the first four months after the FDNPP accident

16

as part of the Fukushima Health Management Survey (Ishikawa et al. 2015). These answer

17

sheets were self-administered, and thus their quality was greatly dependent on each subject's

18

memory. Missing or mistaken memories would be likely to occur although the behaviors right19

after the nuclear accident are expected to have been vividly retained in one’s memory due to20

many impressive events for the residents, e.g., the immediate evacuation, the heavy traffic jam

21

during evacuation, the successive explosive events at the FDNPP, and so on. Second, the22locations of individuals during their evacuations were not strictly accurate in this study because

23of the assumption of a uniform linear motion between the places of departure and destination24(as noted earlier). This problem would be solved by taking int account the realistic movement25

of individuals on the roadmap (Appendix B). Third, uncertainties accompany the parameters

26

for the dose calculations, i.e., the ventilation volume and the dose reduction factor due to staying
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indoors. The ventilation volume depends on the exercise level (sleep, sitting, light exercise,2

heavy exercise), which ranges from 0.45 to 3.0 m3 hr−1 for adults and from 0.42 to 2.92 m3 hr−1

3

for 15-yr-olds (ICRP 1995). The actual ventilation volumes of the subjects could be somewhat

4higher than the reference values used in this study, considering the situations under the urgent

5

evacuation. Regarding the dose reduction factor, Ishikawa et al. (2014) demonstrated that the6indoor-to-outdoor air concentration ratios for 131I (particulate) and 137Cs in Chiba Prefecture

7

after the FDNPP accident were 0.64 and 0.58, respectively. Another study (JAERI 1987)8reported that the ratios for aerosols and iodine gas were 0.62–0.72 and 0.45–0.74, respectively,

9in Japanese buildings based on observations of the fallout that originated from the Chernobyl

10

nuclear power plant accident. Based on these studies, the indoor shielding factor of 0.5 applied

11

in the present study would be reasonable in general.

12

In conclusion, regarding Cs, it is currently difficult to apply the ATDM simulation to the13

estimation of the early internal doses to individuals. The method considerably underestimated14

the residual 137Cs body contents of the subjects from their WBC measurements. Persuasive

15

reasons for this could not been obtained in this study; however, through the above

16

considerations, the discrepancy between the ATDM simulation and WBC measurements can be17

expected to have been due to multiple reasons: (1) the underestimation of the ATDM prediction

18

and the overestimation of the early intake from the WBC measurements due to the conservative

19

intake scenario not assuming potential additional intake, and (2) uncertainties in the parameters20

used in the dose calculations. The direct comparison of the WBC data containing many low

21

values (below the MDA) with the ATDM data would also amplify the discrepancy. Further

22

studies are necessary to clarify the discrepancy between these two methods and to determine23

the precise magnitude of the inhalation dose from the FDNPP accident.

24
25

ACKNOWLEDGEMENTS

26

We appreciate Dr. Haruyasu Nagai of the Japan Atomic Energy Agency for providing valuable
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data of the latest ATDM simulation by WSPEEDI-II.

2
3

FUNDING

4This study was financially supported in part by the Ministry of the Environment of Japan.

5

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Footnote*National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa,Inage-ku, Chiba-city, Chiba 263-8555, Japan

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List of figure captions

Fig. 1. The locations of Fukushima Prefecture, Ibaraki Prefecture, Namie-town, and its adjacentmunicipalities (reproduced from Igarashi et al. 2020).
Fig. 2. Representative evacuation scenarios for Namie-town's residents. Scenario 7: The first
evacuation route is from the town office (departure at 12:00) to the Tsushima vitalization center(arrival at 15:00) on 12 March, and the second evacuation route is from the Tsushimavitalization center (departure at 10:00) to the Adachi gymnasium in Nihonmatsu-city (arrival at
14:00) on 16 March. Scenario 13: The first evacuation is the same as that in Scenario 7, and thesecond evacuation is from the Tsushima vitalization center (departure at 10:00) to the Adachi
gymnasium in Nihonmatsu-city (arrival at 14:00) on 23 March. The circles in the figure denote
the rough locations of the offices of each administrative district. The national roads (Route 114
and Route 6, partly drawn in the figure) were thought to be used by most of the residents ofNamie-town for their evacuation.
Fig. 3. The locations of individuals on the maps with the superimposed 137Cs air concentrations
at the ground level on 12 March. The concentric circles on the maps are drawn with the FDNPP
at the center. The 137Cs air concentrations are provided as hourly-averaged data, and the startingtime is denoted at the top of each panel (left panel: 8:00, middle panel: 15:00, and right panel:
18:00). The symbols in the figure denote the four groups of residents (see text).
Fig. 4. The locations of individuals on the maps with the 137Cs air concentrations at the groundlevel on 15 March. The concentric circles on the maps are drawn with the FDNPP at the center.
The 137Cs air concentrations are provided as hourly-averaged data, and the starting time isdenoted at the top of each panel (left panel: 9:00, middle panel: 15:00, and right panel: 21:00).
The symbols in the figure denote each of the four resident groups (see text).
Fig. 5. The ratio of subjects staying outside the 20-km radius of the FDNPP for each group (seethe text). Left panel: The period from 12 to 15 March. Right panel: The period from 12 to 25
March.
Fig. 6. The total 137Cs intake amounts (Bq) for each group based on the ATDM simulation. The
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boxes cover the 25th percentile to the 75th percentile of the distribution. The right panel
expands the vertical axis of the left panel to make it easy to see the distribution in the small
range. The lines in the boxes are the 50th percentile (median) of the distribution. The whiskers
cover the first quantile ‒ 1.5  IQR (interquartile range) to the third quintile + 1.5  IQR. The
outliers are marked as circles.

Fig. 7. The relative daily 137Cs intake amounts (Bq) for each group of the subjects with their
total 137Cs intake exceeding 500 Bq. Left panel: G1(T) and G2(T). Right panel: G1(M) andG2(M). Error bars: 1.
Fig. 8. The residual 137Cs body contents (Bq) for each group. Left panel: ATDM simulation.
Right panel: WBC measurement. The figure is in the same format as Fig. 6. The individuals
with no detection in the WBC measurements are treated as zero (in the right panel). The 50th
percentile of the distribution is not seen in the G1(T) group or G2(T) group in the WBC
measurements due to the large number of subjects without detection. All subjects with detection
are displayed as outliers for G1(T) group.
Fig. 9. The 137Cs whole-body retention rate as a function of the number of elapsed days after
intake along with the number of WBC measurements on each day.
Fig. 10. Comparison of the daily-integrated values of the 137Cs air concentration between the
ATDM simulation and the SPM data at Haramachi (Minamisoma-city) (left panel) andFukushima-city (right panel). The SPM data for Fukushima-city are the average and 1 of four
locations in the city.

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Appendix A
The locations of individuals and the 137Cs air concentration on the map at every hour on 12, 13,
15, 16, 18, 19, 20 and 21 March (Fig. A1 to Fig. A32). The concentric circles on the maps are
drawn with the FDNPP at the center. The 137Cs air concentration is provided as hourly-averaged
data, and the starting time is denoted at the top of each panel. The symbols in the figure denotethe four groups of residents: prompt evacuees moving toward Tsushima: G1(T) (n=231), lateevacuees moving toward Tsushima: G2(T) (n=37), prompt evacuees moving toward
Minamisoma: G1(M) (n=64), and late evacuees moving toward Minamisoma: G2(M) (n=24).

Appendix B
The daily integrated 137Cs air concentration (Bq m−3 hr) at different locations on Route 114(denoted by 'A') and Route 6 (denoted by 'B').

35

TableTable 1. The CEDs (mSv) for the Adults and 15-yr subjects among the G1(T), G2(T), G1(M),and G2(M) groups (reproduced from Table 5 in Igarashi et al. 2020).

a

Adults and 15yr groups

G1(T)

G2(T)

G1(M)

G2(M)

No. of subjects

231

37

64

24

CED: max.

4.9  10−1

6.1  10−1

1.2  10−1

7.2  10−195th percentile

1.2  10−1

2.9  10−1

1.0  10−1

3.0  10−1

90th percentile

6.4  10−2

1.5  10−1

7.7  10−2

2.8  10−1

75th percentile

n.d.a

8.9  10−2

4.4  10−2

1.4  10−1

50th percentile (median)n.d.

6.2  10−2n.d.

4.1  10−2

n.d.: not detected in the WBC measurements. CED: committed effective dose.

TableTable 2. The time chart of countermeasures by Namie-town along with evacuation orders by
the Japanese central government.
Date and time,

Events†2011
11 March

12 March

14:46‡The disaster countermeasure headquarters was established in Namietown.

21:23

The evacuation order to the area within the 3-km radius of F1 andthe order to take shelter indoors for the area within 3–10 km of F1.

5:44

The evacuation order to the area within the 10-km radius of F1.
The emergency broadcast system of Namie-town announced theevacuation order to the area within the 10-km radius of F1 andinstructed residents to evacuate to the west part of the town (and to
Tsushima's elementary school or Tsushima's junior high school via

6:35‡

Route 114 for individuals who could evacuate by themselves).
7:15

Same as the above, but Tsushima's rehabilitation center andTsushima's branch of Namie-town's high school were added to thedesignated shelters.

‡

The evacuation order to the area within the 3-km radius of F2 and7:45

the order to take shelter indoors for the area within 3–10 km of F2.

8:40‡

Evacuation to shelters outside the 10-km radius of F1 using buses.
The emergency broadcast system of Namie-town announced that the

14:47

‡

17:39

The evacuation order to the area within the 10-km radius of F2.

18:25

The evacuation order to the area within the 20-km radius of F1.

18:25‡
15 March

town office was moving to the Tsushima branch (completed at
16:45).

Hirusone district (located at the border of the 20-km radius of F1).
The town mayor requested Nihonmatsu-city to accept evacuees(approval).

7:30‡

10:00

The order to evacuate individuals who evacuated in the east of‡

The evacuation order to areas outside the 20-km radius of F1, andthe disaster countermeasure headquarters was transferred to
Nihonmatsu-city.

11:00
13:00
5 April‡The order to take shelter indoors for the area within 20–30 km of F1.
‡

Starting voluntary evacuation by private vehicles and buses.
The subsequent mass evacuation was started.

†

F1: Fukushima Daiichi Nuclear Power Plant, F2: Fukushima Daini Nuclear Power Plant.

‡

Countermeasures by Namie-town.

TableTable 3. Comparison of the time-integrated 137Cs air concentration values (Bq m−3 hr) from 12
to 22 March between the ATDM simulation and the SPM data.
Haramachi(Minamisoma-

Soma-city

city)

Shinchi-

Fukushima-

Nihonmatsu-

town

city

city

ATDM

7,450

3,900

3,830

80

20

SPM†

5,660

3,120

930

52040‡950¶

The last digit of the values is rounded.
†

The data below detection limits (D.L.) were treated as D.L.

‡

The average and 1 of the SPM data at four locations in Fukushima-city.

¶

No measurements on 12–14 or 17–20 March.

Appendix_B_Table B1

Table B1. The latitude and longitude of the points listed in Tables B2 and B3
Location ID

LatitudeLongitude

Location ID

LatitudeLongitudeS

37.495503

141.001648

A1

37.495768

140.983629

B1

37.508107

140.997701

A2

37.504654

140.942209

B237.524159

140.998829

A3

37.506077

140.910863

B337.543834

141.007335

A4

37.515075

140.891326

B437.563552

141.002349

A5

37.526104

140.879751

B537.579662

141.009811

A6

37.541736

140.86151

B6

37.603416

141.005654

A7

37.553386

140.834195

B737.612799

141.004335

A8

37.567287

140.800218

B8

37.636412

140.984145

A937.559674

140.761499

B937.650519

140.985436

A10

37.565547

140.743662

B10

37.678635

140.981321

A11

37.582256

140.719519

B1137.702782

140.970943

A12

37.587623

140.690285

B1237.729433

140.953269

A13

37.601039

140.67481

B1337.743687

140.954165

A14

37.633008

140.639842

B1437.760653

140.948646

A15

37.662754

140.595236

B15

37.791024

140.94395

A16

37.667619

140.576224

B1637.808674

140.943432

A17

37.682376

140.5628

B1737.838212

140.937562

A18

37.684875

140.548837

B1837.897808

140.90169

A19

37.691433

140.52427

A20

37.712967

140.502611

A21

37.733697

140.47813

A22

37.756645

140.473572

Appendix_B_Table B2

Table B2. The daily accumulated 137Cs air concentration (Bq m−3 hr) at different locations on Routes 114
Location

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

S

2,847

3,378

3,431

3,471

3,471

3,471

25,98660,144

83,88983,89084,13984,13984,66385,77585,79585,79586,361

88,29599,08599,400

A1

2,324

2,814

2,814

5,036

5,048

5,048

24,83033,571

46,242

46,244

46,382

46,382

46,486

46,773

46,77846,77846,99749,64455,81955,921

A2

1,818

1,994

1,994

35,40335,57135,571

46,764

46,77647,94747,95047,98647,98647,99348,09948,104

48,104

48,401

49,834

51,66051,664

A3

136

138

138

35,54635,68035,68042,31842,31842,99943,00543,03643,03643,03743,09443,09443,094

43,13043,191

43,234

43,234

A4

124

135

135

11,975

12,174

12,174

20,43820,43820,94420,94820,971

20,971

20,973

21,032

21,032

21,032

21,186

21,453

21,49021,490

A5

2

2

2

15,095

15,656

15,656

23,841

23,841

24,292

24,301

24,32024,32024,321

24,36424,36424,364

24,37824,394

24,412

24,412

A6

10

10

10

7,570

8,104

8,104

21,90821,90822,284

22,292

22,30922,30922,31022,35522,35522,35522,36722,386

22,402

22,402

A7

0

0

0

4,817

5,463

5,463

13,40913,40913,782

13,79013,80513,80513,805

13,842

13,842

13,842

13,842

13,843

13,846

13,846

A8

1

1

1

2,352

2,726

2,726

5,579

5,579

5,899

5,901

5,913

5,913

5,913

5,945

5,945

5,945

5,945

5,945

5,945

5,945

A9

0

0

0

1,673

1,832

1,832

2,660

2,660

2,774

2,775

2,785

2,785

2,785

2,802

2,802

2,802

2,802

2,802

2,802

2,802

A10

0

0

0

1,250

1,359

1,359

1,525

1,525

1,537

1,538

1,544

1,544

1,544

1,557

1,557

1,557

1,557

1,557

1,557

1,557

A11

0

0

0

884

1,232

1,232

1,418

1,418

1,462

1,464

1,473

1,473

1,473

1,484

1,484

1,484

1,484

1,484

1,484

1,484

A12

0

0

0

667

705

705

718

718

723

725

730

730

730

736

736

736

736

736

736

736

A13

0

0

0

443

446

446

446

446

453

457

463

463

463

464

464

464

464

464

464

464

A14

0

0

0

339

340

340

340

340

365

374

380

380

380

381

381

381

381

381

381

381

A15

0

0

0

187

191

191

191

191

225

238

244

244

244

245

245

245

245

245

245

245

A16

0

0

0

63

64

64

64

64

89

103

107

107

107

108

108

108

108

108

108

108

A17

0

0

0

61

64

64

64

64

94

103

108

108

108

109

109

109

109

109

109

109

A18

0

0

0

61

64

64

64

64

94

103

108

108

108

109

109

109

109

109

109

109

A19

0

0

0

12

14

14

14

14

45

55

59

59

59

60

60

60

60

60

60

60

A20

0

0

0

6

8

8

8

8

49

61

65

65

65

66

66

66

66

66

66

66

A21

0

0

0

6

8

8

8

8

49

61

65

65

65

66

66

66

66

66

66

66

A22

0

0

0

5

8

8

8

8

59

72

77

77

77

78

78

78

78

78

78

78

The values are integrated for the period until the end of March 2011. The 137Cs air concentration data were obtained from those at the nearest grid to each location in thecalculation domain by WSPEEDI-II.

Appendix_B_Table B3

Table B3. The daily accumulated 137Cs air concentration (Bq m−3 hr) at different locations on Route 6
Location

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

B1

2,847

3,378

3,431

3,471

3,471

3,471

25,98660,144

83,88983,89084,13984,13984,66385,77585,79585,79586,361

88,29599,08599,400

B2

3,582

4,177

4,192

4,195

4,195

4,195

8,687

29,966

40,76040,76140,89540,895

41,157

41,797

41,797

41,79742,18742,73250,67050,841

B3

3,262

3,961

3,966

3,967

3,967

3,967

6,119

20,28928,90828,90928,981

28,981

29,13329,54229,54229,542

29,78430,20735,66735,707

B4

3,262

3,961

3,966

3,967

3,967

3,967

6,119

20,28928,90828,90928,981

28,981

29,13329,54229,54229,542

29,78430,20735,66735,707

B5

1,947

2,691

2,700

2,700

2,700

2,700

4,818

16,032

26,054

26,055

26,105

26,105

26,205

26,46826,46826,46826,661

27,08830,67530,678

B6

1,286

2,041

2,066

2,066

2,066

2,066

4,036

14,57021,366

21,367

21,406

21,406

21,472

21,63021,63021,63021,791

22,11825,16825,169

B7

1,286

2,041

2,066

2,066

2,066

2,066

4,036

14,57021,366

21,367

21,406

21,406

21,472

21,63021,63021,63021,791

22,11825,16825,169

B8

558

1,220

1,232

1,232

1,232

1,232

3,568

8,046

11,150

11,151

11,220

11,220

11,253

11,431

11,431

11,431

11,487

11,715

12,83912,839

B9

684

1,319

1,353

1,353

1,353

1,353

3,403

7,426

10,194

10,194

10,246

10,246

10,272

10,423

10,423

10,423

10,45910,702

11,785

11,785

B10

886

1,491

1,550

1,550

1,550

1,550

3,207

8,149

10,26910,26910,30910,30910,331

10,437

10,437

10,437

10,458

10,68911,958

11,958

B11

886

1,491

1,550

1,550

1,550

1,550

3,207

8,149

10,26910,26910,30910,30910,331

10,437

10,437

10,437

10,458

10,68911,958

11,958

B12

757

1,339

1,361

1,363

1,364

1,364

2,569

5,037

6,584

6,584

6,633

6,633

6,646

6,757

6,757

6,757

6,757

6,959

7,790

7,790

B13

668

1,165

1,213

1,215

1,215

1,215

2,138

4,938

6,244

6,244

6,284

6,284

6,296

6,389

6,389

6,389

6,389

6,532

7,470

7,470

B14

650

1,095

1,170

1,171

1,171

1,171

1,882

4,330

5,338

5,339

5,372

5,373

5,384

5,456

5,456

5,456

5,456

5,571

6,555

6,559

B15

618

1,045

1,131

1,132

1,132

1,132

1,749

4,329

5,194

5,195

5,225

5,226

5,239

5,286

5,286

5,286

5,287

5,398

6,357

6,373

B16

618

1,045

1,131

1,132

1,132

1,132

1,749

4,329

5,194

5,195

5,225

5,226

5,239

5,286

5,286

5,286

5,287

5,398

6,357

6,373

B17

576

1,011

1,107

1,107

1,107

1,107

1,618

4,781

5,590

5,591

5,616

5,618

5,629

5,659

5,659

5,659

5,661

5,760

6,639

6,660

B18

386

623

630

631

631

631

715

3,265

3,682

3,682

3,701

3,703

3,713

3,728

3,728

3,728

3,729

3,755

4,432

4,476

The values are integrated for the period until the end of March 2011. The 137Cs air concentration data were obtained from those at the nearest grid to each location in the calculation
domain by WSPEEDI-II.

Figure1

Fig. 1

Figure2

Fig. 2

Figure3

Fig. 3

Figure4

Fig. 4

Figure5

Ratio of evacuees outside 20-km radius (%)

100%
90%
80%

G1(T)
G2(T)
G1(M)
G2(M)

70%
60%
50%
40%
30%
20%
10%
0%
3/12

3/13

Date

Fig. 5

3/14

3/15

Figure6

1000

6000

800

4000
600
3000
400
2000

137

Cs intake amount (Bq)

5000

200

1000
0

G1(T) G1(T) G2(T) G2(T) G1(M) G1(M) G2(M) G2(M)Adult 15yr Adult 15yr Adult 15yr Adult 15yr

0

Fig. 6

G1(T) G1(T) G2(T) G2(T) G1(M) G1(M) G2(M) G2(M)Adult 15yr Adult 15yr Adult 15yr Adult 15yr

Figure7

1.0
0.9
0.8

0.7
0.6
0.5
0.4
0.3

0.8
0.7
0.6
0.5
0.4
0.3

0.2

0.2

0.1

0.1

0.0

12

13

14

15

16

17

18

19

20

21

22

23

24

25

G1(M)
G2(M)

0.9

Relative intake

Relative intake

1.0

G1(T)
G2(T)

0.0

Date (March 2011)

Fig. 7

12

13

14

15

16

17 18 19 20
Date (March 2011)

21

22

23

24

25

Figure8

8000

ATDM

7000

600

6000

Cs body content (Bq)

700

500
400
300

137

137

Cs body content (Bq)

800

200
100
0

WBC

5000
4000
3000
2000
1000

G1(T)

G2(T)

G1(M)

G2(M)

Fig. 8

0

G1(T)

G2(T)

G1(M)

G2(M)

Figure9

Fig. 9Figure10

3000

ATDM

Haramachi (Minamisoma)

SPM

2500
2000
1500
1000
500
0

300
137Cs air concentration (Bq m-3 24h)

137Cs air concentration (Bq m -3 24h)

3500

3/12 3/13 3/14 3/15 3/16 3/17 3/18 3/19 3/20 3/21 3/22
Date

Fig. 10

ATDM
250

Fukushimashi

SPM

200
150
100

50
0

3/12 3/13 3/14 3/15 3/16 3/17 3/18 3/19 3/20 3/21 3/22
Date(1/6)
Appendix_A_Figure
A1

12:00 a.m. on 12 March 2011

(2/6)

1:00 a.m. on 12 March 2011

(3/6)

2:00 a.m. on 12 March 2011

(4/6)

3:00 a.m. on 12 March 2011

(5/6)

4:00 a.m. on 12 March 2011

(6/6)

5:00 a.m. on 12 March 2011

Fig. A1. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 12 March (1/6), 1:00 a.m. on 12 March (2/6), 2:00 a.m. on 12 March (3/6), 3:00 a.m.
on 12 March (4/6), 4:00 a.m. on 12 March (5/6), and 5:00 a.m. on 12 March (6/6).

(1/6)
Appendix_A_Figure
A2

6:00 a.m. on 12 March 2011

(2/6)

7:00 a.m. on 12 March 2011

(3/6)

8:00 a.m. on 12 March 2011

(4/6)

9:00 a.m. on 12 March 2011

(5/6)

10:00 a.m. on 12 March 2011

(6/6)

11:00 a.m. on 12 March 2011

Fig. A2. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 12 March (1/6), 7:00 a.m. on 12 March (2/6), 8:00 a.m. on 12 March (3/6), 9:00 a.m.
on 12 March (4/6), 10:00 a.m. on 12 March (5/6), and 11:00 a.m. on 12 March (6/6).

(1/6)
Appendix_A_Figure
A3

12:00 p.m. on 12 March 2011

(2/6)

1:00 p.m. on 12 March 2011

(3/6)

2:00 p.m. on 12 March 2011

(4/6)

3:00 p.m. on 12 March 2011

(5/6)

4:00 p.m. on 12 March 2011

(6/6)

5:00 p.m. on 12 March 2011

Fig. A3. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 12 March (1/6), 1:00 p.m. on 12 March (2/6), 2:00 p.m. on 12 March (3/6), 3:00
p.m. on 12 March (4/6), 4:00 p.m. on 12 March (5/6), and 5:00 p.m. on 12 March (6/6).

(1/6)
Appendix_A_Figure
A4

6:00 p.m. on 12 March 2011

(2/6)

7:00 p.m. on 12 March 2011

(3/6)

8:00 p.m. on 12 March 2011

(4/6)

9:00 p.m. on 12 March 2011

(5/6)

10:00 p.m. on 12 March 2011

(6/6)

11:00 p.m. on 12 March 2011

Fig. A4. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 12 March (1/6), 7:00 p.m. on 12 March (2/6), 8:00 p.m. on 12 March (3/6), 9:00 p.m.
on 12 March (4/6), 10:00 p.m. on 12 March (5/6), and 11:00 p.m. on 12 March (6/6).

(1/6)
Appendix_A_Figure
A5

12:00 a.m. on 13 March 2011

(2/6)

1:00 a.m. on 13 March 2011

(3/6)

2:00 a.m. on 13 March 2011

(4/6)

3:00 a.m. on 13 March 2011

(5/6)

4:00 a.m. on 13 March 2011

(6/6)

5:00 a.m. on 13 March 2011

Fig. A5. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 13 March (1/6), 1:00 a.m. on 13 March (2/6), 2:00 a.m. on 13 March (3/6), 3:00 a.m.
on 13 March (4/6), 4:00 a.m. on 13 March (5/6), and 5:00 a.m. on 13 March (6/6).

(1/6)
Appendix_A_Figure
A6

6:00 a.m. on 13 March 2011

(2/6)

7:00 a.m. on 13 March 2011

(3/6)

8:00 a.m. on 13 March 2011

(4/6)

9:00 a.m. on 13 March 2011

(5/6)

10:00 a.m. on 13 March 2011

(6/6)

11:00 a.m. on 13 March 2011

Fig. A6. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 13 March (1/6), 7:00 a.m. on 13 March (2/6), 8:00 a.m. on 13 March (3/6), 9:00 a.m.
on 13 March (4/6), 10:00 a.m. on 13 March (5/6), and 11:00 a.m. on 13 March (6/6).

(1/6)
Appendix_A_Figure
A7

12:00 p.m. on 13 March 2011

(2/6)

1:00 p.m. on 13 March 2011

(3/6)

2:00 p.m. on 13 March 2011

(4/6)

3:00 p.m. on 13 March 2011

(5/6)

4:00 p.m. on 13 March 2011

(6/6)

5:00 p.m. on 13 March 2011

Fig. A7. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 13 March (1/6), 1:00 p.m. on 13 March (2/6), 2:00 p.m. on 13 March (3/6), 3:00
p.m. on 13 March (4/6), 4:00 p.m. on 13 March (5/6), and 5:00 p.m. on 13 March (6/6).

(1/6)
Appendix_A_Figure
A8

6:00 p.m. on 13 March 2011

(2/6)

7:00 p.m. on 13 March 2011

(3/6)

8:00 p.m. on 13 March 2011

(4/6)

9:00 p.m. on 13 March 2011

(5/6)

10:00 p.m. on 13 March 2011

(6/6)

11:00 p.m. on 13 March 2011

Fig. A8. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 13 March (1/6), 7:00 p.m. on 13 March (2/6), 8:00 p.m. on 13 March (3/6), 9:00 p.m.
on 13 March (4/6), 10:00 p.m. on 13 March (5/6), and 11:00 p.m. on 13 March (6/6).

(1/6)
Appendix_A_Figure
A9

12:00 a.m. on 15 March 2011

(2/6)

1:00 a.m. on 15 March 2011

(3/6)

2:00 a.m. on 15 March 2011

(4/6)

3:00 a.m. on 15 March 2011

(5/6)

4:00 a.m. on 15 March 2011

(6/6)

5:00 a.m. on 15 March 2011

Fig. A9. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 15 March (1/6), 1:00 a.m. on 15 March (2/6), 2:00 a.m. on 15 March (3/6), 3:00 a.m.
on 15 March (4/6), 4:00 a.m. on 15 March (5/6), and 5:00 a.m. on 15 March (6/6).

(1/6)
Appendix_A_Figure
A10

6:00 a.m. on 15 March 2011

(2/6)

7:00 a.m. on 15 March 2011

(3/6)

8:00 a.m. on 15 March 2011

(4/6)

9:00 a.m. on 15 March 2011

(5/6)

10:00 a.m. on 15 March 2011

(6/6)

11:00 a.m. on 15 March 2011

Fig. A10. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 15 March (1/6), 7:00 a.m. on 15 March (2/6), 8:00 a.m. on 15 March (3/6), 9:00 a.m.
on 15 March (4/6), 10:00 a.m. on 15 March (5/6), and 11:00 a.m. on 15 March (6/6).

(1/6)
Appendix_A_Figure
A11

12:00 p.m. on 15 March 2011

(2/6)

1:00 p.m. on 15 March 2011

(3/6)

2:00 p.m. on 15 March 2011

(4/6)

3:00 p.m. on 15 March 2011

(5/6)

4:00 p.m. on 15 March 2011

(6/6)

5:00 p.m. on 15 March 2011

Fig. A11. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 15 March (1/6), 1:00 p.m. on 15 March (2/6), 2:00 p.m. on 15 March (3/6), 3:00 p.m.
on 15 March (4/6), 4:00 p.m. on 15 March (5/6), and 5:00 p.m. on 15 March (6/6).

(1/6)
Appendix_A_Figure
A12

6:00 p.m. on 15 March 2011

(2/6)

7:00 p.m. on 15 March 2011

(3/6)

8:00 p.m. on 15 March 2011

(4/6)

9:00 p.m. on 15 March 2011

(5/6)

10:00 p.m. on 15 March 2011

(6/6)

11:00 p.m. on 15 March 2011

Fig. A12. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 15 March (1/6), 7:00 p.m. on 15 March (2/6), 8:00 p.m. on 15 March (3/6), 9:00 p.m.
on 15 March (4/6), 10:00 p.m. on 15 March (5/6), and 11:00 p.m. on 15 March (6/6).

(1/6)
Appendix_A_Figure
A13

12:00 a.m. on 16 March 2011

(2/6)

1:00 a.m. on 16 March 2011

(3/6)

2:00 a.m. on 16 March 2011

(4/6)

3:00 a.m. on 16 March 2011

(5/6)

4:00 a.m. on 16 March 2011

(6/6)

5:00 a.m. on 16 March 2011

Fig. A13. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 16 March (1/6), 1:00 a.m. on 16 March (2/6), 2:00 a.m. on 16 March (3/6), 3:00 a.m.
on 16 March (4/6), 4:00 a.m. on 16 March (5/6), and 5:00 a.m. on 16 March (6/6).

(1/6)
Appendix_A_Figure
A14

6:00 a.m. on 16 March 2011

(2/6)

7:00 a.m. on 16 March 2011

(3/6)

8:00 a.m. on 16 March 2011

(4/6)

9:00 a.m. on 16 March 2011

(5/6)

10:00 a.m. on 16 March 2011

(6/6)

11:00 a.m. on 16 March 2011

Fig. A14. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 16 March (1/6), 7:00 a.m. on 16 March (2/6), 8:00 a.m. on 16 March (3/6), 9:00 a.m.
on 16 March (4/6), 10:00 a.m. on 16 March (5/6), and 11:00 a.m. on 16 March (6/6).

(1/6)
Appendix_A_Figure
A15

12:00 p.m. on 16 March 2011

(2/6)

1:00 p.m. on 16 March 2011

(3/6)

2:00 p.m. on 16 March 2011

(4/6)

3:00 p.m. on 16 March 2011

(5/6)

4:00 p.m. on 16 March 2011

(6/6)

5:00 p.m. on 16 March 2011

Fig. A15. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 16 March (1/6), 1:00 p.m. on 16 March (2/6), 2:00 p.m. on 16 March (3/6), 3:00 p.m.
on 16 March (4/6), 4:00 p.m. on 16 March (5/6), and 5:00 p.m. on 16 March (6/6).

(1/6)
Appendix_A_Figure
A16

6:00 p.m. on 16 March 2011

(2/6)

7:00 p.m. on 16 March 2011

(3/6)

8:00 p.m. on 16 March 2011

(4/6)

9:00 p.m. on 16 March 2011

(5/6)

10:00 p.m. on 16 March 2011

(6/6)

11:00 p.m. on 16 March 2011

Fig. A16. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 16 March (1/6), 7:00 p.m. on 16 March (2/6), 8:00 p.m. on 16 March (3/6), 9:00 p.m. on
16 March (4/6), 10:00 p.m. on 16 March (5/6), and 11:00 p.m. on 16 March (6/6).

(1/6)
Appendix_A_Figure
A17

12:00 a.m. on 18 March 2011

(2/6)

1:00 a.m. on 18 March 2011

(3/6)

2:00 a.m. on 18 March 2011

(4/6)

3:00 a.m. on 18 March 2011

(5/6)

4:00 a.m. on 18 March 2011

(6/6)

5:00 a.m. on 18 March 2011

Fig. A17. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 18 March (1/6), 1:00 a.m. on 18 March (2/6), 2:00 a.m. on 18 March (3/6), 3:00 a.m.
on 18 March (4/6), 4:00 a.m. on 18 March (5/6), and 5:00 a.m. on 18 March (6/6).

(1/6)
Appendix_A_Figure
A18

6:00 a.m. on 18 March 2011

(2/6)

7:00 a.m. on 18 March 2011

(3/6)

8:00 a.m. on 18 March 2011

(4/6)

9:00 a.m. on 18 March 2011

(5/6)

10:00 a.m. on 18 March 2011

(6/6)

11:00 a.m. on 18 March 2011

Fig. A18. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 18 March (1/6), 7:00 a.m. on 18 March (2/6), 8:00 a.m. on 18 March (3/6), 9:00 a.m. on
18 March (4/6), 10:00 a.m. on 18 March (5/6), and 11:00 a.m. on 18 March (6/6).

(1/6)
Appendix_A_Figure
A19

12:00 p.m. on 18 March 2011

(2/6)

1:00 p.m. on 18 March 2011

(3/6)

2:00 p.m. on 18 March 2011

(4/6)

3:00 p.m. on 18 March 2011

(5/6)

4:00 p.m. on 18 March 2011

(6/6)

5:00 p.m. on 18 March 2011

Fig. A19. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 18 March (1/6), 1:00 p.m. on 18 March (2/6), 2:00 p.m. on 18 March (3/6), 3:00 p.m.
on 18 March (4/6), 4:00 p.m. on 18 March (5/6), and 5:00 p.m. on 18 March (6/6).

(1/6)
Appendix_A_Figure
A20

6:00 p.m. on 18 March 2011

(2/6)

7:00 p.m. on 18 March 2011

(3/6)

8:00 p.m. on 18 March 2011

(4/6)

9:00 p.m. on 18 March 2011

(5/6)

10:00 p.m. on 18 March 2011

(6/6)

11:00 p.m. on 18 March 2011

Fig. A20. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 18 March (1/6), 7:00 p.m. on 18 March (2/6), 8:00 p.m. on 18 March (3/6), 9:00 p.m.
on 18 March (4/6), 10:00 p.m. on 18 March (5/6), and 11:00 p.m. on 18 March (6/6).

(1/6)
Appendix_A_Figure
A21

12:00 a.m. on 19 March 2011

(2/6)

1:00 a.m. on 19 March 2011

(3/6)

2:00 a.m. on 19 March 2011

(4/6)

3:00 a.m. on 19 March 2011

(5/6)

4:00 a.m. on 19 March 2011

(6/6)

5:00 a.m. on 19 March 2011

Fig. A21. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 19 March (1/6), 1:00 a.m. on 19 March (2/6), 2:00 a.m. on 19 March (3/6), 3:00 a.m.
on 19 March (4/6), 4:00 a.m. on 19 March (5/6), and 5:00 a.m. on 19 March (6/6).

(1/6)
Appendix_A_Figure
A22

6:00 a.m. on 19 March 2011

(2/6)

7:00 a.m. on 19 March 2011

(3/6)

8:00 a.m. on 19 March 2011

(4/6)

9:00 a.m. on 19 March 2011

(5/6)

10:00 a.m. on 19 March 2011

(6/6)

11:00 a.m. on 19 March 2011

Fig. A22. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 19 March (1/6), 7:00 a.m. on 19 March (2/6), 8:00 a.m. on 19 March (3/6), 9:00 a.m. on
19 March (4/6), 10:00 a.m. on 19 March (5/6), and 11:00 a.m. on 19 March (6/6).

(1/6)
Appendix_A_Figure
A23

12:00 p.m. on 19 March 2011

(2/6)

1:00 p.m. on 19 March 2011

(3/6)

2:00 p.m. on 19 March 2011

(4/6)

3:00 p.m. on 19 March 2011

(5/6)

4:00 p.m. on 19 March 2011

(6/6)

5:00 p.m. on 19 March 2011

Fig. A23. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 19 March (1/6), 1:00 p.m. on 19 March (2/6), 2:00 p.m. on 19 March (3/6), 3:00 p.m.
on 19 March (4/6), 4:00 p.m. on 19 March (5/6), and 5:00 p.m. on 19 March (6/6).

(1/6)
Appendix_A_Figure
A24

6:00 p.m. on 19 March 2011

(2/6)

7:00 p.m. on 19 March 2011

(3/6)

8:00 p.m. on 19 March 2011

(4/6)

9:00 p.m. on 19 March 2011

(5/6)

10:00 p.m. on 19 March 2011

(6/6)

11:00 p.m. on 19 March 2011

Fig. A24. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 19 March (1/6), 7:00 p.m. on 19 March (2/6), 8:00 p.m. on 19 March (3/6), 9:00 p.m. on
19 March (4/6), 10:00 p.m. on 19 March (5/6), and 11:00 p.m. on 19 March (6/6).

(1/6)
Appendix_A_Figure
A25 12:00 a.m. on 20 March 2011

(2/6)

1:00 a.m. on 20 March 2011

(3/6)

2:00 a.m. on 20 March 2011

(4/6)

3:00 a.m. on 20 March 2011

(5/6)

4:00 a.m. on 20 March 2011

(6/6)

5:00 a.m. on 20 March 2011

Fig. A25. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 20 March (1/6), 1:00 a.m. on 20 March (2/6), 2:00 a.m. on 20 March (3/6), 3:00 a.m.
on 20 March (4/6), 4:00 a.m. on 20 March (5/6), and 5:00 a.m. on 20 March (6/6).

(1/6)
Appendix_A_Figure
A26 6:00 a.m. on 20 March 2011

(2/6)

7:00 a.m. on 20 March 2011

(3/6)

8:00 a.m. on 20 March 2011

(4/6)

9:00 a.m. on 20 March 2011

(5/6)

10:00 a.m. on 20 March 2011

(6/6)

11:00 a.m. on 20 March 2011

Fig. A26. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 20 March (1/6), 7:00 a.m. on 20 March (2/6), 8:00 a.m. on 20 March (3/6), 9:00 a.m. on
20 March (4/6), 10:00 a.m. on 20 March (5/6), and 11:00 a.m. on 20 March (6/6).

(1/6)
Appendix_A_Figure
A27 12:00 p.m. on 20 March 2011

(2/6)

1:00 p.m. on 20 March 2011

(3/6)

2:00 p.m. on 20 March 2011

(4/6)

3:00 p.m. on 20 March 2011

(5/6)

4:00 p.m. on 20 March 2011

(6/6)

5:00 p.m. on 20 March 2011

Fig. A27. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 20 March (1/6), 1:00 p.m. on 20 March (2/6), 2:00 p.m. on 20 March (3/6), 3:00 p.m.
on 20 March (4/6), 4:00 p.m. on 20 March (5/6), and 5:00 p.m. on 20 March (6/6).

(1/6)
Appendix_A_Figure
A28 6:00 p.m. on 20 March 2011

(2/6)

7:00 p.m. on 20 March 2011

(3/6)

8:00 p.m. on 20 March 2011

(4/6)

9:00 p.m. on 20 March 2011

(5/6)

10:00 p.m. on 20 March 2011

(6/6)

11:00 p.m. on 20 March 2011

Fig. A28. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 20 March (1/6), 7:00 p.m. on 20 March (2/6), 8:00 p.m. on 20 March (3/6), 9:00 p.m. on
20 March (4/6), 10:00 p.m. on 20 March (5/6), and 11:00 p.m. on 20 March (6/6).

(1/6)
Appendix_A_Figure
A29

12:00 a.m. on 21 March 2011

(2/6)

1:00 a.m. on 21 March 2011

(3/6)

2:00 a.m. on 21 March 2011

(4/6)

3:00 a.m. on 21 March 2011

(5/6)

4:00 a.m. on 21 March 2011

(6/6)

5:00 a.m. on 21 March 2011

Fig. A29. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 a.m. on 21 March (1/6), 1:00 a.m. on 21 March (2/6), 2:00 a.m. on 21 March (3/6), 3:00 a.m.
on 21 March (4/6), 4:00 a.m. on 21 March (5/6), and 5:00 a.m. on 21 March (6/6).

6:00 a.m. on 21 March 2011

(2/6)

7:00 a.m. on 21 March 2011

(3/6)

8:00 a.m. on 21 March 2011

(4/6)

9:00 a.m. on 21 March 2011

(5/6)

10:00 a.m. on 21 March 2011

(6/6)

11:00 a.m. on 21 March 2011

(1/6)
Appendix_A_Figure
A30

Fig. A30. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 a.m. on 21 March (1/6), 7:00 a.m. on 21 March (2/6), 8:00 a.m. on 21 March (3/6), 9:00 a.m.
on 21 March (4/6), 10:00 a.m. on 21 March (5/6), and 11:00 a.m. on 21 March (6/6).

(1/6)
Appendix_A_Figure
A31

12:00 p.m. on 21 March 2011

(2/6)

1:00 p.m. on 21 March 2011

(3/6)

2:00 p.m. on 21 March 2011

(4/6)

3:00 p.m. on 21 March 2011

(5/6)

4:00 p.m. on 21 March 2011

(6/6)

5:00 p.m. on 21 March 2011

Fig. A31. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 12:00 p.m. on 21 March (1/6), 1:00 p.m. on 21 March (2/6), 2:00 p.m. on 21 March (3/6), 3:00 p.m.
on 21 March (4/6), 4:00 p.m. on 21 March (5/6), and 5:00 p.m. on 21 March (6/6).

(1/6)
Appendix_A_Figure
A32

6:00 p.m. on 21 March 2011

(2/6)

7:00 p.m. on 21 March 2011

(3/6)

8:00 p.m. on 21 March 2011

(4/6)

9:00 p.m. on 21 March 2011

(5/6)

10:00 p.m. on 21 March 2011

(6/6)

11:00 p.m. on 21 March 2011

Fig. A32. The locations of individuals on the maps with the 137Cs air concentration at the ground levelat 6:00 p.m. on 21 March (1/6), 7:00 p.m. on 21 March (2/6), 8:00 p.m. on 21 March (3/6), 9:00 p.m.
on 21 March (4/6), 10:00 p.m. on 21 March (5/6), and 11:00 p.m. on 21 March (6/6).

Appendix_B_FigureB1

Fig. B1 The locations of the points listed in Tables B2 and B3.