a global meta-analysis of particulate and gaseous air pollutants in relation to covid-19 mortality and hospitalization

A growing body of evidence implicates ambient air pollution in the exacerbation of clinical outcomes after sars-cov-2 infection. to synthesize this evidence, we performed a global systematic review and meta-analysis to precisely quantify the associations between exposure to specific atmospheric  ontaminants and the subsequent risks of covid-19-related mortality and hospital admission. our methodology adhered to the preferred reporting items for systematic reviews and meta-analyses (prisma) framework, involving a comprehensive search of scientific databases for literature published until the end of august 2025. from this search, 44 publications were deemed eligible for inclusion. we employed random-effects models to compute summary risk ratios (rrs) representing the change in health risk per 1 µg/m³ increment in atmospheric pollutant concentration. our findings indicate that long term exposure to fine particulate matter (pm2.5), coarse particles (pm₁₀), nitrogen dioxide (no₂), and sulfur dioxide (so₂) significantly increased the likelihood of fatal outcomes from covid-19. the respective pooled rrs were 1.046 (95% ci: 1.031–1.062), 1.079 (95% ci: 1.005–1.154), 1.017 (95% ci: 1.004–1.029), and 1.077 (95% ci: 1.021–1.133). acute exposures to ambient pm2.5 and no₂ concentrations were similarly associated with increased mortality, demonstrating risk ratios of 1.043 (95% ci: 1.033–1.053) and 1.033 (95% ci: 1.019–1.048) respectively per 1 µg/m³ increment. additionally, both acute and chronic exposures to pm2.5, pm₁₀, and no₂ showed significant associations with higher covid-19 hospitalization rates. this meta-analysis provides robust quantitative suggestion that ambient pm2.5, pm10, no₂, and so₂ are significant and modifiable risk factors for severe covid-19 outcomes. these results emphasize the critical need for enhanced air quality standards as a fundamental element of public health policy to alleviate the impact of covid-19 and bolster defenses against forthcoming respiratory epidemics.