Table 1. Statistic summary for weather conditions, air pollution and pediatric outpatient visits for asthma during the cold spell and non-cold spell periods.
| Period | Mean (Minimum, Maximum) | |||
| Mean temperature | Relative humidity | O3 | Asthma outpatients | |
| All Cold spells | 1.4 (−3.2, 2.9) | 62.4 (29.5, 95) | 13.3 (4.8, 33.9) | 53 (20, 104) |
| Non-cold spells during cold season | 10.3 (−0.8, 22.5) | 70.5 (34.5, 96.8) | 20.6 (0.6, 59.5) | 43 (7, 121) |
| 20 days cold spell in 2008 | 1.4 (0, 2.6) | 75.8 (59, 95) | 16.1 (4.8, 33.9) | 53 (24, 82) |
| The same period in 2007 | 7.3 (3.1,14.9) | 65.4 (48.0, 91.3) | 12.1 (6.1, 20.5) | 38 (18, 68) |
| The same period in 2009 | 6.8 (−3.2, 12.3) | 73.3 (21.5, 91.8) | 14.4 (3.3, 35.4) | 38 (19, 62) |