Meteorological Conditions and PM2.5 Impact on COVID-19 Case Fatality Ratios (CFR) in Bangkok Metropolitan Region

The emergence of a novel coronavirus strain triggered a global health crisis, impacting both health and economies worldwide, including Thailand since 2019. While prior research hinted at connections between environmental factors and rising COVID-19 cases, these links remained inconclusive. This study investigated indoor and outdoor (I/O) ratios and explored potential correlations between fine particulate matter (PM2.5), meteorological conditions, and the case fatality rate (CFR%) of COVID-19 in Bangkok and its metropolitan area from January to December 2021. In Spearman’s Rank correlation analysis, the results found that CFR% exhibited a positive correlation with relative humidity (RH) (r=0.187) and a negative correlation with PM2.5 (r=-0.190) and wind speed (WS) (r=-0.039). The generalized additive model (GAM) indicated that RH, PM2.5, temperature, and WS adversely affect the CFR% of COVID-19. Consistent relationships between PM2.5, RH, and WS were observed in both Spearman’s Rank correlation and the GAM model. This study underscored the complexity of understanding pandemic dynamics across seasons, I/O ratios, and the influence of lag days. By presenting the results, they may serve as a valuable reference for planning interventions during future pandemics.