Table 2.
Characteristics of the air pollutants in different cities
| Type | City | Median (P25–P75) | Days* |
|---|---|---|---|
| CO | Tianjin | 1.72 (1.37–2.29) | 250 |
| Xi’an | 1.70 (1.26–2.47) | 211 | |
| Xingtai | 1.54 (1.11–2.46) | 198 | |
| – | – | – | |
| Guangzhou | 1.00 (0.89–1.19) | 27 | |
| Fuzhou | 0.73 (0.63–0.94) | 10 | |
| Guiyang | 0.77 (0.63–0.95) | 10 | |
| NO2 | Xingtai | 61.79 (47.67–82.99) | 232 |
| Chengdu | 51.76 (42.45–65.44) | 178 | |
| Ji’nan | 49.70 (35.48–68.42) | 162 | |
| – | – | – | |
| Kunming | 36.50 (28.90–44.51) | 26 | |
| Dalian | 28.94 (23.58–37.33) | 17 | |
| Guiyang | 31.05 (24.03–39.59) | 16 | |
| O3 | Wuhan | 79.06 (51.67–110.33) | 181 |
| Shanghai | 77.55 (58.89–96.12) | 165 | |
| Ji’nan | 72.48 (40.46–102.40) | 160 | |
| – | – | – | |
| Zunyi | 64.79 (57.48–73.13) | 31 | |
| Hefei | 55.23 (38.77–67.33) | 29 | |
| Fuzhou | 49.42 (39.63–62.93) | 27 | |
| PM10 | Xingtai | 251.43 (172.92–359.36) | 308 |
| Ji’nan | 166.03 (120.06–237.78) | 215 | |
| Xi’an | 143.05 (98.79–218.76) | 173 | |
| – | – | – | |
| Shenzhen | 59.83 (38.44–94.45) | 19 | |
| Kunming | 72.19 (46.77–99.89) | 15 | |
| Fuzhou | 62.29 (45.56–87.95) | 14 | |
| PM2.5 | Xingtai | 119.29 (78.09–196.94) | 258 |
| Ji’nan | 84.93 (59.76–129.42) | 192 | |
| Tianjin | 80.58 (54.03–113.46) | 178 | |
| – | – | – | |
| Shenzhen | 36.92 (21.18–58.11) | 27 | |
| Fuzhou | 31.65 (20.53–49.52) | 12 | |
| Kunming | 37.88 (24.00–53.04) | 9 | |
| SO2 | Xingtai | 84.58 (51.71–137.72) | 291 |
| Ji’nan | 61.47 (40.98–104.46) | 256 | |
| Shenyang | 40.98 (24.26–98.12) | 169 | |
| – | – | – | |
| Wenzhou | 20.14 (13.46–29.00) | 13 | |
| Guangzhou | 20.19 (15.07–26.22) | 6 | |
| Shenzhen | 9.83 (7.43–14.57) | 1 |
* The days of a specific city that the pollutant concentration exceeds the “extreme value”