Data on atmospheric 129I concentrations and 129I/137Cs ratios for suspended air particulate matter dispersed in eastern Japan just after the 2011 nuclear accident in Fukushima, Japan

Mitsuru Ebihara; Naoki Shirai; Yasuji Oura; Haruo Tsuruta; Hiroyuki Matsuzaki; Yuichi Moriguchi

doi:10.1016/j.dib.2022.108621

Data on atmospheric ¹²⁹I concentrations and ¹²⁹I/¹³⁷Cs ratios for suspended air particulate matter dispersed in eastern Japan just after the 2011 nuclear accident in Fukushima, Japan

Data Brief. 2022 Sep 28:45:108621. doi: 10.1016/j.dib.2022.108621. eCollection 2022 Dec.

Authors

Mitsuru Ebihara^{1

2}, Naoki Shirai², Yasuji Oura², Haruo Tsuruta³, Hiroyuki Matsuzaki⁴, Yuichi Moriguchi⁵

Affiliations

¹ Department of Earth Sciences, Waseda University, 1-6-1 Nishi-waseda, Shinjuku-ku, Tokyo 169-8050, Japan.
² Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
³ Remoto Sensing Technology Center of Japan, 3-17-1 Toranomon, Minato-ku 105-0001, Japan.
⁴ Department of Nuclear Engeneering and Management, School of Engineering, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
⁵ National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8508, Japan.

Abstract

Data of the atmospheric activity concentrations (in Bq/m³) of ¹²⁹I dispersed into the environment as aerosol immediately after the nuclear accident at Fukushima Daiichi Nuclear Power Plant in 2011 are presented. The radioactivity of ¹²⁹I was determined in suspended particulate matter (SPM) collected on filter tapes at 41 SPM monitoring sites in Fukushima and other prefectures in eastern Japan including the metropolitan area. For quantitative determination of ¹²⁹I in SPM samples by accelerator mass spectrometry (AMS), ¹²⁹I was chemically separated. Prior to the ¹²⁹I measurement, the ¹³⁷Cs activity was determined for the same SPM sample by gamma-ray spectrometry using Ge-semiconductor detectors. Combining activity concentrations of the two nuclides, an activity ratio of ¹²⁹I/¹³⁷Cs (in Bq/Bq) was calculated for each SPM sample. In our research project, atmospheric activity concentrations of ¹²⁹I and ¹³⁷Cs, and their activity ratios were obtained for 920 SPM samples. Scientific discussion related to those data was described in the research article entitled "Time-series variations of atmospheric ¹²⁹I concentrations and ¹²⁹I/¹³⁷Cs ratios in eastern Japan just after the 2011 nuclear accident in Fukushima, Japan" (Ebihara et al. 2022), where 363 data sets were presented. The remaining 557 data sets are presented in this article, so this data article makes up for the original research article (Ebihara et al. 2022). Blank values were obtained for whole analytical procedure. In addition, those for reagents and filters (both bland-new and used filters) were analyzed for assessing the contribution of the ¹²⁹I activity from these samples. Those data also are presented in this article.

Keywords: 129I; 137Cs; Fukushima nuclear accident; Metropolitan area; Radioactive nuclides; Suspended particulate matter (SPM); Time-series variation.