Table 2.
Incidence and incidence rate ratio of CRS for the three levels of pollutant exposure.
| Pollutants | Levels | n of CRS | Person Years | Incidence Rate | Incidence Rate Ratio | 95% CI | |
|---|---|---|---|---|---|---|---|
| SO2 | Low | 1770 | 607,762 | 2.91 | 1.00 | ||
| Moderate | 2271 | 737,033 | 3.08 | 1.07 | 1.00 | 1.13 | |
| High | 1216 | 534,141 | 2.28 | 0.79 | 0.73 | 0.85 | |
| CO | Low | 1801 | 665,244 | 2.71 | 1.00 | ||
| Moderate | 1794 | 599,002 | 2.99 | 1.09 | 1.03 | 1.17 | |
| High | 1662 | 614,690 | 2.70 | 0.99 | 0.93 | 1.06 | |
| PM2.5 | Low | 1529 | 624,050 | 2.45 | 1.00 | ||
| Moderate | 1864 | 628,477 | 2.97 | 1.18 | 1.10 | 1.26 | |
| High | 1864 | 626,409 | 2.98 | 1.16 | 1.09 | 1.24 | |
| NO2 | Low | 1756 | 645,644 | 2.72 | 1.00 | ||
| Moderate | 1854 | 636,774 | 2.91 | 1.06 | 0.99 | 1.13 | |
| High | 1647 | 596,519 | 2.76 | 1.02 | 0.95 | 1.09 | |
| PM10 | Low | 1733 | 699,227 | 2.48 | 1.00 | ||
| Moderate | 1766 | 589,134 | 3.00 | 1.17 | 1.10 | 1.25 | |
| High | 1758 | 590,575 | 2.98 | 1.16 | 1.08 | 1.24 | |
Incidence rate (1000 person-years); CI, confidence interval; The annual average air pollutant concentrations were categorized into 3 groups based on tertiles for each air pollutant.