Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight doses

BackgroundGalactic cosmic radiation (GCR) is a naturally occurring environmental radiation that originates from outer space. GCR is modulated by solar activity, and its intensity increases with increasing geomagnetic latitude and altitude, reaching a peak of up to approximately 20 km in the atmosphe...

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Main Authors: Hiroshi Yasuda, Hiroto Motoyama, Kazuaki Yajima
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Public Health
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Online Access:https://www.frontiersin.org/articles/10.3389/fpubh.2025.1554332/full
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author Hiroshi Yasuda
Hiroshi Yasuda
Hiroto Motoyama
Kazuaki Yajima
author_facet Hiroshi Yasuda
Hiroshi Yasuda
Hiroto Motoyama
Kazuaki Yajima
author_sort Hiroshi Yasuda
collection DOAJ
description BackgroundGalactic cosmic radiation (GCR) is a naturally occurring environmental radiation that originates from outer space. GCR is modulated by solar activity, and its intensity increases with increasing geomagnetic latitude and altitude, reaching a peak of up to approximately 20 km in the atmosphere. Therefore, commercial flight passengers (flyers) are exposed to elevated levels of cosmic radiation while flying onboard commercial aircraft. Although the recent COVID-19 pandemic, which began in early 2020, is believed to have significantly affected public exposure to cosmic radiation, this impact is yet to be quantified.MethodsBased on the official records of Japanese flyers, their annual per-capita doses (APCDs) of cosmic radiation exposure on international and domestic flights were calculated using the established code JISCARD EX over a 7-year period from 2014 to 2020 (including the first year of the pandemic). For estimating the APCDs on international flights, the world was divided into eight regions. The aviation route dose to a representative city in each region was determined at three cruising altitudes: 34,000 ft. (10.4 km), 37,000 ft. (11.3 km), and 40,000 ft. (12.2 km).ResultsAt a typical cruising altitude of 37,000 ft., the flyer-average APCD from international flights was estimated to be approximately 60 μSv y−1, while the APCD from domestic flights was approximately 2 μSv y−1 over the target period, including the pandemic year (2020). These results indicate that the distribution of Japanese travel destinations did not change significantly during the pandemic period. In contrast, the population-average APCD significantly decreased from approximately 10 μSv y−1 in the pre-pandemic period (2014–2019) to 2 μSv y−1 in 2020, representing a reduction of more than 80%, which corresponds to a decline in the number of travelers.ConclusionThe results of this study indicate that the population-average APCD of Japanese flyers decreased significantly during the COVID-19 pandemic, while the flyer-average APCD remained largely unchanged. Further studies will be performed to determine APCDs for the subsequent period and to assess the overall effect of the pandemic on public health.
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spelling doaj-art-4d9265779ed849bfb9d89cb6de472edb2025-08-20T02:12:53ZengFrontiers Media S.A.Frontiers in Public Health2296-25652025-04-011310.3389/fpubh.2025.15543321554332Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight dosesHiroshi Yasuda0Hiroshi Yasuda1Hiroto Motoyama2Kazuaki Yajima3Research Institute for Radiation Biology and Medicine (RIRBM), Hiroshima University, Hiroshima, JapanSchool of Medicine, Hiroshima University, Hiroshima, JapanSchool of Medicine, Hiroshima University, Hiroshima, JapanNational Institutes for Quantum Science and Technology, Chiba, JapanBackgroundGalactic cosmic radiation (GCR) is a naturally occurring environmental radiation that originates from outer space. GCR is modulated by solar activity, and its intensity increases with increasing geomagnetic latitude and altitude, reaching a peak of up to approximately 20 km in the atmosphere. Therefore, commercial flight passengers (flyers) are exposed to elevated levels of cosmic radiation while flying onboard commercial aircraft. Although the recent COVID-19 pandemic, which began in early 2020, is believed to have significantly affected public exposure to cosmic radiation, this impact is yet to be quantified.MethodsBased on the official records of Japanese flyers, their annual per-capita doses (APCDs) of cosmic radiation exposure on international and domestic flights were calculated using the established code JISCARD EX over a 7-year period from 2014 to 2020 (including the first year of the pandemic). For estimating the APCDs on international flights, the world was divided into eight regions. The aviation route dose to a representative city in each region was determined at three cruising altitudes: 34,000 ft. (10.4 km), 37,000 ft. (11.3 km), and 40,000 ft. (12.2 km).ResultsAt a typical cruising altitude of 37,000 ft., the flyer-average APCD from international flights was estimated to be approximately 60 μSv y−1, while the APCD from domestic flights was approximately 2 μSv y−1 over the target period, including the pandemic year (2020). These results indicate that the distribution of Japanese travel destinations did not change significantly during the pandemic period. In contrast, the population-average APCD significantly decreased from approximately 10 μSv y−1 in the pre-pandemic period (2014–2019) to 2 μSv y−1 in 2020, representing a reduction of more than 80%, which corresponds to a decline in the number of travelers.ConclusionThe results of this study indicate that the population-average APCD of Japanese flyers decreased significantly during the COVID-19 pandemic, while the flyer-average APCD remained largely unchanged. Further studies will be performed to determine APCDs for the subsequent period and to assess the overall effect of the pandemic on public health.https://www.frontiersin.org/articles/10.3389/fpubh.2025.1554332/fullcosmic radiationcommercial flightaviation doseJapaneseper-capitaCOVID-19 pandemic
spellingShingle Hiroshi Yasuda
Hiroshi Yasuda
Hiroto Motoyama
Kazuaki Yajima
Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight doses
Frontiers in Public Health
cosmic radiation
commercial flight
aviation dose
Japanese
per-capita
COVID-19 pandemic
title Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight doses
title_full Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight doses
title_fullStr Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight doses
title_full_unstemmed Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight doses
title_short Recent trends in cosmic radiation exposure onboard aircraft: effects of the COVID-19 pandemic on Japanese in-flight doses
title_sort recent trends in cosmic radiation exposure onboard aircraft effects of the covid 19 pandemic on japanese in flight doses
topic cosmic radiation
commercial flight
aviation dose
Japanese
per-capita
COVID-19 pandemic
url https://www.frontiersin.org/articles/10.3389/fpubh.2025.1554332/full
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