Table 1 Descriptive statistics of outpatient visits for children with respiratory diseases, weather conditions, and concentrations of air pollutants by seasons in Harbin from January 1, 2013, to December 31, 2019
Season | Variables | Mean | SD | Min | P25 | P50 | P75 | Max |
|---|---|---|---|---|---|---|---|---|
Whole year | Daily counts, mean | 413.74 | 198.94 | 62.00 | 244.00 | 400.50 | 537.00 | 1407.00 |
|  | Mean temperature (°C) | 4.51 | 15.55 | -33.50 | -10.30 | 7.10 | 18.41 | 30.80 |
| Â | Relative humidity (%) | 65.43 | 14.91 | 15.00 | 56.50 | 67.00 | 76.00 | 98.00 |
|  | PM10 (µg/m3) | 83.17 | 67.56 | 1.00 | 42.00 | 65.00 | 101.05 | 844.92 |
|  | N02 (µg/m3) | 43.74 | 20.64 | 10.00 | 29.00 | 39.00 | 54.00 | 161.17 |
|  | SO2 (µg/m3) | 31.47 | 35.73 | 2.82 | 8.50 | 16.96 | 41.00 | 233.36 |
Warm | Daily counts, mean | 391.65 | 175.77 | 96.00 | 248.00 | 385.00 | 496.00 | 1407.00 |
|  | Mean temperature (°C) | 17.36 | 6.48 | -3.20 | 13.30 | 18.40 | 22.20 | 30.80 |
| Â | Relative humidity (%) | 66.64 | 17.29 | 15.00 | 56.00 | 70.00 | 80.00 | 98.00 |
|  | PM10 (µg/m3) | 63.76 | 45.12 | 11.00 | 35.00 | 51.70 | 79.17 | 518.00 |
|  | N02 (µg/m3) | 34.32 | 13.11 | 10.00 | 25.00 | 32.00 | 40.00 | 107.83 |
|  | SO2 (µg/m3) | 11.06 | 6.79 | 2.82 | 7.00 | 9.00 | 13.00 | 48.58 |
Cold | Daily counts, mean | 435.94 | 217.59 | 62.00 | 242.50 | 414.00 | 582.00 | 1217.00 |
|  | Mean temperature (°C) | -8.40 | 10.50 | -33.50 | -16.60 | -10.30 | 0.30 | 20.65 |
| Â | Relative humidity (%) | 64.22 | 11.95 | 19.00 | 56.80 | 65.00 | 73.00 | 97.00 |
|  | PM10 (µg/m3) | 102.66 | 79.69 | 1.00 | 53.00 | 79.00 | 124.52 | 844.92 |
|  | N02 (µg/m3) | 53.19 | 22.43 | 11.00 | 37.00 | 50.00 | 65.23 | 161.17 |
|  | SO2 (µg/m3) | 51.97 | 40.92 | 4.91 | 23.61 | 40.92 | 66.50 | 233.36 |