Ozone Pollutants and the Onset of COVID-19 Symptoms in Chiba Prefecture, Japan

Abstract

<jats:title>Abstract</jats:title> <jats:p>Background We examined the association between ozone pollutants in the breathing air and the onset of symptoms of COVID-19 infection. Methods We accessed online data of positive COVID-19 cases published by the Chiba Prefectural Government, including their ID, residence, age, sex, the dates of onset of symptoms, and tested positive with COVID-19. The daily data ozone concentrations were derived from an online database of 20 weather stations in the prefecture. The data of daily onset of symptoms of 735 patients were linked with the daily data of ozone concentrations. We estimated the number of daily person-years by dividing the number of the population by 365 (days). The incidence rate ratio and 95% confidence interval (IRR, 95% CI) were estimated by the levels of ozone concentrations. Results There was a significant positive association between the date of symptom onset and levels of ozone concentrations. Adjusted IRR, 95% CI, tertile_3 vs. tertile_1, was 1.69 (1.26, 2.26) for total participants, <jats:italic>p</jats:italic> for trend = 0.000. The positive association was observed in women but not in men, adjusted IRR, 95% CI, tertile_3 vs. tertile_1: 3.18 (1.94, 5.22), and 1.07 (0.73, 1.57), respectively. The positive association was seen for the sub-groups of ages under 60 but not 60+, adjusted IRR, 95% CI, tertile_3 vs. tertile_1: 1.90 (1.37, 2.65) and 1.10 (0.57, 2.17), respectively. Conclusions Ozone pollutants affect susceptibility to COVID-19 in the onset of symptoms. The findings warrant further studies on the mechanism of how ozone pollutants affect susceptibility to COVID-19.</jats:p>