Table 1.
Descriptive statistics
| Obs. | Mean | Std. dev. | Min | Max | |
|---|---|---|---|---|---|
| Non-Hubei cities | |||||
| AQI | 38,491 | 67.232 | 46.805 | 9.083 | 500.000 |
| SO2 | 38,491 | 11.451 | 8.989 | 1.000 | 142.500 |
| PM25 | 38,491 | 42.981 | 39.286 | 1.292 | 1188.583 |
| PM10 | 38,491 | 69.709 | 70.068 | 3.261 | 2767.833 |
| NO2 | 38,490 | 25.223 | 14.854 | 1.458 | 123.250 |
| CO | 38,491 | 0.805 | 0.424 | 0.100 | 7.422 |
| Temperature | 38,467 | 81.435 | 96.074 | − 307.714 | 286.750 |
| Wind_Speed | 38,467 | 26.165 | 11.351 | 3.000 | 106.286 |
| Precipitation | 37,276 | 5.322 | 13.260 | − 1.000 | 162.563 |
| Migration | 38,499 | 4.136 | 1.267 | 0.300 | 8.505 |
| Cities in Hubei province, excluding Wuhan | |||||
| AQI | 1353 | 65.594 | 29.479 | 16.444 | 218.579 |
| SO2 | 1353 | 9.072 | 4.499 | 2.250 | 38.095 |
| PM25 | 1353 | 44.264 | 24.374 | 5.250 | 168.737 |
| PM10 | 1353 | 62.535 | 27.757 | 8.957 | 177.947 |
| NO2 | 1353 | 20.708 | 10.288 | 3.125 | 63.667 |
| CO | 1353 | 0.928 | 0.302 | 0.299 | 1.973 |
| Temperature | 1353 | 111.815 | 60.795 | − 10.014 | 274.569 |
| Wind_Speed | 1353 | 22.528 | 8.049 | 7.000 | 60.757 |
| Precipitation | 1353 | 6.250 | 13.359 | − 0.250 | 83.260 |
| Migration | 1353 | 3.482 | 1.564 | 0.944 | 6.741 |
| Wuhan | |||||
| AQI | 123 | 61.153 | 26.770 | 15.778 | 143.125 |
| SO2 | 123 | 8.176 | 2.754 | 4.958 | 16.875 |
| PM25 | 123 | 41.738 | 21.730 | 8.500 | 108.875 |
| PM10 | 123 | 57.451 | 25.911 | 12.875 | 134.542 |
| NO2 | 123 | 28.939 | 12.815 | 9.833 | 75.375 |
| CO | 123 | 0.896 | 0.219 | 0.471 | 1.557 |
| Temperature | 123 | 113.599 | 62.754 | 4.753 | 269.906 |
| Wind_Speed | 123 | 24.730 | 8.279 | 10.927 | 57.240 |
| Precipitation | 123 | 6.629 | 12.865 | 0.000 | 83.260 |
| Migration | 123 | 1.896 | 1.520 | 0.569 | 5.334 |