barely significantp = 0.051
Similarly, in another cross-sectional nationwide study using zero-inflated negative binomial models to estimate the association between long-term (2010–2016) county-level exposures to NO 2 , PM 2.5 , and ozone and COVID-19 case-fatality and mortality rates, PM 2.5 was significantly associated with COVID-19 mortality rates when a single pollutant model was used but was barely significant (MRR 1.15; 95% CI 1.00–1.32; p = 0.051) in a tri-pollutant model, whereas NO 2 levels remained positively associated with both COVID-19 case-fatality and mortality rates [ 75 ].