Impacts on air dose rates after the Fukushima accident over the North Pacific from 19 March 2011 to 2 September 2015

Kuo-Ying Wang; Philippe Nedelec; Hannah Clark; Neil Harris; Mizuo Kajino; Yasuhito Igarashi

doi:10.1371/journal.pone.0272937

Impacts on air dose rates after the Fukushima accident over the North Pacific from 19 March 2011 to 2 September 2015

PLoS One. 2022 Aug 24;17(8):e0272937. doi: 10.1371/journal.pone.0272937. eCollection 2022.

Authors

Kuo-Ying Wang¹, Philippe Nedelec², Hannah Clark³, Neil Harris⁴, Mizuo Kajino⁵, Yasuhito Igarashi⁶

Affiliations

¹ Department of Atmospheric Sciences, National Central University, Chung-Li, Taiwan.
² Laboratoire d'Aérologie, Centre National de la Recherche Scientifique, Observatoire Midi-Pyrénées, Toulouse, France.
³ IAGOS-AISBL, 98 Rue du Trône, Brussels, Belgium.
⁴ Centre for Environment and Agricultural Informatics, Cranfield University, Cranfield, United Kingdom.
⁵ Meteorological Research Institute (MRI), Japan Meteorological Agency (JMA), Tsukuba, Ibaraki, Japan.
⁶ Division of Nuclear Engineering Science, Institute for Integrated Radiation and Nuclear Science, Kyoto University (KURNS), Osaka, Japan.

Abstract

A fleet of thirteen in-service global container ships continuously measured the air dose rates over the North Pacific after the Fukushima Daiichi Nuclear Power Station (FDNPS) accident. The results showed that the elevated air dose rates over the Port of Tokyo and the FDNPS emissions are significantly correlated (log(emission fluxes) = 54.98 x (air dose rates) (R = 0.95, P-value<0.01), and they are also significantly correlated with the Tsukuba deposition fluxes (log(deposition fluxes) = 0.47 + 30.98 (air dose rates) (R = 0.91, P-value<0.01). These results demonstrate the direct impact of the FDNPS emissions on the depositions of radionuclides and the air dose rates over the Port of Tokyo. Over the North Pacific, the correlation equations are log(emission fluxes) = -2.72 + 202.36 x (air dose rates over the northwestern Pacific) (R = 0.40, P-value<0.01), and log(emission fluxes) = -0.55 + 80.19 x (air dose rates over the northeastern Pacific) (R = 0.29, P-value = 0.0424). These results indicate that the resuspension of the deposited radionuclides have become a dominant source in the transport of radionuclides across the North Pacific. Model simulations show underestimated air dose rates during the periods of 22-25 March 2011 and 27-30 March 2011 indicating the lack of mechanisms, such as the resuspension of radionuclides, in the model.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants, Radioactive* / analysis
Cesium Radioisotopes / analysis
Fukushima Nuclear Accident*
Japan
Radiation Monitoring* / methods
Tokyo

Substances

Air Pollutants, Radioactive
Cesium Radioisotopes

Grants and funding

KYW is funded by the Ministry of Science and Technology (www.most.gov.tw; 107-2111-M-008-027-). PN and HC are supported by the the IAGOS project (www.iagos.org). The funders had no role in study design, data collection and analysis, decisionto publish, or preparation of the manuscript.