Table 2:
Descriptive statistics of air pollutants and meteorological factors over the 24 hours before arrhythmia onset
| Variable | Mean | SD | Minimum | 25th percentile | 50th percentile | 75th percentile | Maximum |
|---|---|---|---|---|---|---|---|
| PM2.5, μg/m3 | 34.4 | 25.8 | 4.0 | 16.0 | 27.0 | 45.0 | 137.0 |
| PM2.5–10, μg/m3 | 25.5 | 21.6 | 0.0 | 10.0 | 20.0 | 35.0 | 110.0 |
| NO2, μg/m3 | 27.5 | 18.4 | 4.0 | 13.0 | 22.0 | 37.0 | 86.0 |
| SO2, μg/m3 | 8.9 | 5.6 | 2.0 | 5.0 | 7.0 | 11.0 | 33.0 |
| CO, mg/m3 | 0.7 | 0.3 | 0.2 | 0.5 | 0.7 | 0.9 | 1.9 |
| O3, μg/m3 | 59.0 | 39.2 | 3.0 | 28.0 | 53.0 | 84.0 | 172.0 |
| Temperature, °C | 17.5 | 9.0 | −5.0 | 11.0 | 18.8 | 24.9 | 32.8 |
| Relative humidity, % | 71.4 | 21.0 | 21.0 | 56.0 | 75.0 | 90.0 | 100.0 |
Note: CO = carbon monoxide, NO2 = nitrogen dioxide, O3 = ozone, PM2.5 = particulate matter with an aerodynamic diameter ≤ 2.5 μm, PM2.5–10 = particulate matter with an aerodynamic diameter between 2.5 and 10 μm, SD = standard deviation, SO2 = sulfur dioxide.