ORs* and 95% CIs for associations between the cumulative effects of ambient air pollutants over 0–3 days (per IQR increase) and emergency department visits for COVID-19
| Characteristics | PM2.5 | NO2 | O3 |
| Age (in years) | |||
| <65 | 1.016 (1.007–1.026) I2=50.6% (<0.01) | 1.024 (1.016–1.033) I2=21.9% (0.15) | 1.002 (0.996–1.009) I2=16.1% (0.22) |
| ≥65 | 1.012 (1.001–1.023) I2=25.9% (0.11) | 1.034 (1.018–1.050) I2=46.7% (<0.01) | 0.994 (0.989–1.000) I2=23.8% (0.13) |
| P value for effect modification | 0.72 I2=43.4% (<0.01) | 0.99 I2=44.6% (<0.01) | 0.52 I2=52.6% (<0.01) |
| Sex | |||
| Male | 1.013 (1.003–1.022) I2=37.7% (0.03) | 1.037 (1.022–1.053) I2=50.4% (0.01) | 1.001 (0.994–1.009) I2=56.9% (<0.01) |
| Female | 1.017 (1.008–1.026) I2=41.5% (0.01) | 1.014 (1.006–1.023) I2=87.1% (<0.01) | 1.003 (0.996–1.009) I2=54.2% (<0.01) |
| P value for effect modification | 0.49 I2=41.4% (<0.01) | 0.34 I2=41.4% (<0.01) | 0.51 I2=41.4% (<0.01) |
| COVID-19 case status | |||
| Confirmed | 1.012 (1.004–1.021) I2=47.2% (<0.01) | 1.028 (1.021–1.036) 29.1% (0.08) | 1.000 (0.994–1.006) 70.5% (<0.01) |
| Suspected | 1.010 (1.000–1.021) I2=0.0% (0.68) | 0.985 (0.969–1.000) 0.0% (0.52) | 1.009 (1.005–1.013) 30.4% (0.07) |
| P value for effect modification | 0.84 I2=41.9% (<0.01) | 0.27 I2=30.6% (0.02) | 0.31 I2=60.3% (<0.01) |
| Pneumonia status | |||
| Yes | 0.995 (0.978–1.013) I2=43.8% (<0.01) | 1.017 (1.001–1.033) I2=33.8% (0.05) | 0.998 (0.991–1.004) I2=20.4% (0.18) |
| No | 1.015 (1.011–1.019) I2=32.1% (0.06) | 1.029 (1.021–1.037) I2=34.1% (0.04) | 1.001 (0.995–1.008) I2=65.2% (<0.01) |
| P value for effect modification | 0.64 I2=43.1% (<0.01) | 0.84 I2=37.3% (0.01) | 0.41 I2=50.0% (<0.01) |
| Hospital | |||
| Yes | 1.023 (1.015–1.031) I2=44.2% (0.01) | 1.020 (1.008–1.032) I2=41.5% (0.02) | 1.005 (0.998–1.011) I2=64.1% (<0.01) |
| No | 0.992 (0.980–1.004) I2=37.5% (0.03) | 1.027 (1.020–1.034) I2=21.3% (0.16) | 0.993 (0.988–0.998) I2=34.7% (0.04) |
| P value for effect modification | 0.04 I2=47.7% (<0.01) | 0.84 I2=41.4% (0.00) | 0.01 I2=52.7% (<0.01) |
I2: The variance due to heterogeneity estimated by the I²-statistic for the strata models and the models when calculating the p value for effect modification. In parentheses, the p values for the statistical significance of heterogeneity are reported.
Models represent pooled health region-specific estimates derived using two-stage random effects meta-analysis and meta-regression.
ORs reflect a 6.2 µg/m3 change in PM2.5, a 7.7 ppb change in NO2 and a 10.8 ppb change in O3
*Models represent pooled health region-specific estimates derived using two-stage random effects meta-analysis and meta-regression. ORs reflect a 6.2 µg/m3 change in PM2.5, a 7.7 ppb change in NO2 and a 10.8 ppb change in O3. Models adjusted for daily mean ambient temperature, relative humidity, the effective reproduction number, the OxCGRT Government Response Index and population density and percentage of the population self-identified as Black as meta-predictors.
NO2, nitrogen dioxide; O3, ozone; OxCGRT, Oxford COVID-19 Government Response Tracker; PM2.5, particulate matter with diameter less than 2.5 μm.