Table 7.
Heterogeneity analysis.
| Variables | (1) Ln(AQI) |
(2) Ln(SO2) |
(3) Ln(PM2.5) |
(4) Ln(PM10) |
(5) Ln(NO2) |
(6) Ln(CO) |
(7) Ln(O3) |
|---|---|---|---|---|---|---|---|
| Panel A: 107 cities with high population density (N = 1498) | |||||||
| Treat_Lock (direct effects) | −0.073*** (−4.135) |
0.069*** (2.844) |
−0.100*** (−4.153) |
−0.038 (−1.619) |
0.100*** (4.100) |
0.005 (0.325) |
−0.013 (−0.217) |
| Panel B: 176 cities with low population density (N = 2464) | |||||||
| Treat_Lock (direct effects) | −0.087*** (−3.242) |
−0.007 (−0.009) |
−0.107*** (−3.982) |
−0.064*** (−2.611) |
0.059*** (2.691) |
−0.022 (−1.063) |
−0.017 (−1.021) |
| Panel C: 86 cities with more industrial firms (N = 1204) | |||||||
| Treat_Lock (direct effects) | −0.056** (−2.032) |
0.024 (0.346) |
−0.077*** (−2.585) |
−0.025 (−0.321) |
0.035 (0.725) |
0.021 (0.884) |
−0.081*** (−4.082) |
| Panel D: 197 cities with fewer industrial firms (N = 2758) | |||||||
| Treat_Lock (direct effects) | −0.035** (−2.453) |
0.052*** (2.633) |
−0.057*** (−2.789) |
−0.001 (−0.234) |
0.064*** (3.236) |
−0.020 (−1.005) |
0.020 (1.327) |
| Panel E: 97 cities with heating supply (N = 1358) | |||||||
| Treat_Lock (direct effects) | −0.096*** (−3.541) |
−0.029 (−0.570) |
−0.082*** (−2.641) |
−0.103*** (−3.341) |
0.028 (0.174) |
−0.077*** (−3.321) |
0.010 (0.613) |
| Panel F: 186 cities without heating supply (N = 2604) | |||||||
| Treat_Lock (direct effects) | −0.069*** (−2.973) |
0.028 (1.043) |
−0.092*** (−4.543) |
−0.037 (−1.547) |
0.106*** (4.368) |
−0.023 (−1.443) |
−0.041*** (−2.026) |
| Panel G: 141 cities with a higher transportation demand (N = 1974) | |||||||
| Treat_Lock (direct effects) | −0.092*** (−4.473) |
−0.014 (−0.065) |
−0.115*** (−4.643) |
−0.064** (−2.633) |
0.047 (1.445) |
−0.045*** (−2.691) |
−0.039** (−2.031) |
| Panel H: 142 cities with a lower transportation demand (N = 1988) | |||||||
| Treat_Lock (direct effects) | −0.028 (−1.203) |
0.079*** (3.341) |
−0.037 (−1.310) |
0.009 (0.774) |
0.065*** (2.878) |
−0.027 (−1.640) |
0.018 (1.548) |
| Control variables | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Spatial FE | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Week FE | Yes | Yes | Yes | Yes | Yes | Yes | Yes |