Background: Recent studies conducted in several OECD countries have shown that chronic exposure to elevated levels of air pollutants (especially PM2.5, PM10 and NOx), might negatively impact COVID-19 morbidity and mortality rates. The aim of this study was to examine the association between chronic exposure to air pollution in Israeli cities and towns, their demographic and socioeconomic status, and COVID-19 morbidity, during the three local morbidity waves.
Methods: We examined the associations between: (a) annual average concentrations of NOx, CO, PM10, PM2.5 and SO2 in 2016-2019, and demographic and socioeconomic parameters, and (b) COVID-19 positive cases in 279 Israeli cities and towns, in the four state-wide morbidity peaks: 1st wave peak: March 31st, 2020; 2nd wave peaks: July 24th and September 27th, 2020, and the 3rd wave peak: January 17th, 2021, which occurred after the beginning of the nationwide vaccination campaign. These associations were calculated using both Spearman correlations and multivariate linear regressions.
Results: We found statistically significant positive correlations between the concentrations of most pollutants in 2016-19 and COVID-19 morbidity rate at the first three timepoints but not the 4th (January 17th, 2021). Population density and city/town total population were also positively associated with the COVID-19 morbidity rates at these three timepoints, but not the 4th, in which socioeconomic parameters were more dominant - we found a statistically significant negative correlation between socioeconomic cluster and COVID-19 morbidity. In addition, all multivariate models including PM2.5 concentrations were statistically significant, and PM2.5 concentrations were positively associated with the COVID-19 morbidity rates in all models.
Conclusions: We found a nationwide association between population chronic exposure to five main air pollutants in Israeli cities and towns, and COVID-19 morbidity rates during two of the three morbidity waves experienced in Israel. The widespread morbidity that was related to socioeconomic factors during the 3rd wave, emphasizes the need for special attention to morbidity prevention in socioeconomically vulnerable populations and especially in large household communities. Nevertheless, this ecological study has several limitations, such as the inability to draw conclusions about causality or mechanisms of action. The growing body of evidence, regarding association between exacerbated COVID-19 morbidity and mortality rates and long-term chronic exposure to elevated concentrations of air pollutants should serve as a wake-up call to policy makers regarding the urgent need to reduce air pollution and its harmful effects.
Keywords: COVID-19; Environmental exposure; NOx; PM(10); PM(2.5); Population density; Socioeconomic-cluster; Vaccination campaign.
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