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. 2020 Nov:190:110042.
doi: 10.1016/j.envres.2020.110042. Epub 2020 Aug 12.

Impact of climate and ambient air pollution on the epidemic growth during COVID-19 outbreak in Japan

Kenichi Azuma  1 , Naoki Kagi  2 , Hoon Kim  3 , Motoya Hayashi  4
Affiliations

Impact of climate and ambient air pollution on the epidemic growth during COVID-19 outbreak in Japan

Kenichi Azuma et al. Environ Res. 2020 Nov.

Abstract

Coronavirus disease 2019 (COVID-19) rapidly spread worldwide in the first quarter of 2020 and resulted in a global crisis. Investigation of the potential association of the spread of the COVID-19 infection with climate or ambient air pollution could lead to the development of preventive strategies for disease control. To examine this association, we conducted a longitudinal cohort study of 28 geographical areas of Japan with documented outbreaks of COVID-19. We analyzed data obtained from March 13 to April 6, 2020, before the Japanese government declared a state of emergency. The results revealed that the epidemic growth of COVID-19 was significantly associated with increase in daily temperature or sunshine hours. This suggests that an increase in person-to-person contact due to increased outing activities on a warm and/or sunny day might promote the transmission of COVID-19. Our results also suggested that short-term exposure to suspended particles might influence respiratory infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Further research by well-designed or well-controlled study models is required to ascertain this effect. Our findings suggest that weather has an indirect role in the transmission of COVID-19 and that daily adequate preventive behavior decreases the transmission.

Keywords: COVID-19; Epidemic growth; Particulate matter; Sunshine; Temperature.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Image 1
Graphical abstract
Fig. 1
Fig. 1
Geographic patterns of COVID-19 confirmed case counts (per 1,000,000 inhabitants) in 28 geographical areas of Japan from March 13 to April 6, 2020.
See this image and copyright information in PMC

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