Table 3.

Summary of sensitivity analyses of association of PM_2.5 and COVID-19 incidence.

Model	IRR	95% CI	% cases	% population
Best fitting multivariate model (province as fixed effect)	1.07	0.97–1.18	99.9a	99.6a
Exclude Montréal	1.07	0.96–1.18	72.4	94.5
Exclude 3 provinces with aggregated health regions	1.15	1.00–1.32b	94.6	81
Exclude health regions with population density < median	1.16	1.00–1.34b	94.8	82
Ontario and Quebec only	1.21	1.03–1.40	84.9	61.5
April 19 data (35,986 cases)	1.10	1.01–1.19	99.9	99.6
Best fitting multivariate model (province as random effect)	1.09	0.98–1.21c	99.9a	99.6a

^aFive health regions excluded due to missing data.

^bLower bound >1 with additional decimal places.

^cCorrected for overdispersion by multiplying standard error by square root of dispersion factor (Bolker, 2020).