Table 1.
Nationwide and regional average particulate matter concentrations between December 2008 and December 2016 and the number of outpatient visits for upper respiratory infections in each season in Taiwan from January 2009 to December 2016
| Regions/PM (µg/m3) | Spring | Summer | Fall | Winter | |
| Taiwan | PM2.5 | 30.90 ± 12.30 | 17.97 ± 6.37 | 28.00 ± 10.20 | 34.44 ± 13.10 |
| PM10 | 58.05 ± 27.47 | 35.00 ± 7.74 | 53.96 ± 17.46 | 62.43 ± 21.31 | |
| Northern region | PM2.5 | 27.37 ± 12.43 | 18.63 ± 7.43 | 20.36 ± 10.02 | 25.95 ± 13.78 |
| PM10 | 49.52 ± 33.52 | 33.30 ± 11.64 | 38.63 ± 18.51 | 46.44 ± 24.17 | |
| Central region | PM2.5 | 35.36 ± 16.13 | 20.12 ± 9.37 | 32.99 ± 13.90 | 36.37 ± 15.64 |
| PM10 | 60.55 ± 30.03 | 35.64 ± 11.56 | 57.15 ± 20.32 | 60.30 ± 23.70 | |
| Southern region | PM2.5 | 34.99 ± 17.46 | 17.32 ± 8.71 | 37.33 ± 15.42 | 49.14 ± 15.95 |
| PM10 | 66.75 ± 32.10 | 36.51 ± 11.21 | 70.60 ± 25.93 | 87.42 ± 24.73 | |
| Eastern region | PM2.5 | 15.37 ± 8.05 | 10.36 ± 4.94 | 13.49 ± 7.82 | 15.62 ± 8.73 |
| PM10 | 30.49 ± 15.45 | 24.04 ± 9.86 | 31.85 ± 23.11 | 30.12 ± 14.67 | |
| Regions/URI patients (× 103) | |||||
| Taiwan | Overall | 523.75 ± 93.61 | 375.67 ± 35.07 | 492.46 ± 63.48 | 607.31 ± 124.83 |
| Elderly | 70.13 ± 11.27 | 50.62 ± 4.75 | 60.98 ± 6.91 | 77.52 ± 17.23 | |
| Northern region | Overall | 210.90 ± 35.83 | 148.45 ± 14.46 | 192.93 ± 26.09 | 238.55 ± 53.95 |
| Elderly | 25.10 ± 3.99 | 17.73 ± 1.65 | 20.93 ± 2.55 | 27.19 ± 6.71 | |
| Central region | Overall | 102.77 ± 20.04 | 72.74 ± 7.30 | 97.90 ± 12.79 | 121.29 ± 24.65 |
| Elderly | 13.53 ± 2.23 | 9.63 ± 0.94 | 11.85 ± 1.36 | 14.88 ± 3.27 | |
| Southern region | Overall | 77.95 ± 14.09 | 62.25 ± 7.06 | 78.97 ± 10.53 | 95.38 ± 18.11 |
| Elderly | 11.78 ± 1.91 | 9.57 ± 1.17 | 11.29 ± 1.33 | 13.74 ± 2.78 | |
| Eastern region | Overall | 12.91 ± 2.22 | 8.71 ± 1.12 | 11.41 ± 1.63 | 14.35 ± 2.67 |
| Elderly | 2.29 ± 0.34 | 1.52 ± 0.18 | 1.86 ± 0.24 | 2.51 ± 0.54 | |
PM: Particulate matter; URI: Upper respiratory infection.