Pooled rate ratios (RRs) and 95 % confidence intervals (95% CIs) for the associations of daily air pollution levels with hospitalisation for first acute myocardial infarction by season in the three cities with hospital discharge registers
| Pollutant | Lag | Warm season (Apr–Sep) RR* (95% CI) | Cold season (Oct–Mar) RR (95% CI) |
|---|---|---|---|
| *Rate ratios calculated for a change of 10 000 particles/cm3 in PNC, 10 μg/m3 in PM10, 0.2 mg/m3 in CO, and 8 μg/m3 in NO2. | |||
| †City-specific results heterogeneous (p<0.1), random effects model used for pooling. | |||
| CO | 0 | 1.014 (0.995–1.033) | 1.006 (1.000–1.012) |
| 1 | 1.011 (0.993–1.030) | 1.000† (0.972–1.030) | |
| 2 | 1.017 (1.000–1.035) | 1.001† (0.996–1.007) | |
| 3 | 1.011 (0.993–1.029) | 0.996 (0.990–1.002) | |
| NO2 | 0 | 1.001 (0.985–1.016) | 1.003 (0.990–1.015) |
| 1 | 1.008 (0.993–1.023) | 0.996† (0.970–1.022) | |
| 2 | 1.007 (0.992–1.022) | 1.005 (0.993–1.018) | |
| 3 | 1.012 (0.997–1.027) | 1.000† (0.978–1.022) | |
| PNC | 0 | 1.009 (0.972–1.048) | 1.014 (1.001–1.028) |
| 1 | 1.023 (0.988–1.060) | 1.001† (0.956–1.048) | |
| 2 | 1.050 (1.016–1.085) | 1.001 (0.989–1.014) | |
| 3 | 1.022 (0.987–1.058) | 1.009† (0.971–1.049) | |
| PM10 | 0 | 1.006 (0.990–1.022) | 1.001 (0.991–1.012) |
| 1 | 1.000 (0.985–1.016) | 0.998 (0.987–1.009) | |
| 2 | 1.005 (0.990–1.020) | 1.001 (0.991–1.012) | |
| 3 | 1.010 (0.995–1.025) | 0.991 (0.981–1.002) | |