Table 6.
Heterogeneity analysis
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | |
|---|---|---|---|---|---|---|---|---|---|---|
| South | North | Pop_L | Pop _H | GDP_L | GDP_H | PGDP_L | PGDP_H | Elect_L | Elect_H | |
| Panel A: AQI | ||||||||||
| Migration*lockdown | − 2.706*** | − 4.048*** | − 3.936*** | − 5.067*** | − 3.429*** | − 6.206*** | − 3.764*** | − 5.153*** | − 2.490*** | − 7.612*** |
| (− 8.614) | (− .684) | (− 8.254) | (− 7.091) | (− 7.392) | (− 8.144) | (− 7.518) | (− 7.854) | (− 5.588) | (− 9.861) | |
| Panel B: PM2.5 | ||||||||||
| Migration*lockdown | − 2.132*** | − 2.375*** | − 2.844*** | − 3.891*** | − 2.276*** | − 4.949*** | − 2.431*** | − 4.115*** | − 1.642*** | − 5.687*** |
| (− 8.499) | (− 3.819) | (− 6.877) | (− 6.336) | (− 5.696) | (− 7.505) | (− 5.522) | (− 7.367) | (− 4.410) | (− 8.339) | |
| Panel C: PM10 | ||||||||||
| Migration*lockdown | − 2.229*** | − 7.535*** | − 4.582*** | − 7.698*** | − 4.365*** | − 8.710*** | − 5.083*** | − 6.713*** | − 3.124*** | − 10.443*** |
| (− 6.874) | (− 5.917) | (− 7.687) | (− 5.484) | (− 7.631) | (− 5.685) | (− 8.324) | (− 5.258) | (− 5.838) | (− 6.938) | |
| Panel D: SO2 | ||||||||||
| Migration*lockdown | − 0.050 | − 0.524*** | − 0.629*** | − 0.166** | − 0.569*** | − 0.295*** | − 0.585*** | − 0.279*** | − 0.316*** | − 0.616*** |
| (− 0.856) | (− 4.528) | (− 6.336) | (− 2.016) | (− 5.958) | (− 3.494) | (− 5.945) | (− 3.108) | (− 3.650) | (− 5.702) | |
| Panel E: NO2 | ||||||||||
| Migration*lockdown | − 0.391*** | − 0.601*** | − 0.799*** | − 0.390** | − 0.625*** | − 0.612*** | − 0.556*** | − 0.469*** | − 0.643*** | − 0.358** |
| (− 3.225) | (− 3.834) | (− 6.050) | (− 2.433) | (− 4.939) | (− 3.552) | (− 4.180) | (− 3.000) | (− 5.199) | (− 2.041) | |
| Panel F: CO | ||||||||||
| Migration*lockdown | − 0.018*** | − 0.002 | − 0.020*** | − 0.015*** | − 0.012*** | − 0.027*** | − 0.013*** | − 0.021*** | − 0.004 | − 0.035*** |
| (− 6.258) | (− 0.305) | (− 4.672) | (− 3.042) | (− 2.955) | (− 4.975) | (− 2.889) | (− 4.536) | (− 1.097) | (− 6.232) | |
| Weather | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| City FE | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| City by date trend | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Migration by date trend | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Standard errors are clustered at the city-day level. t statistics are reported below the coefficients in parentheses
“_H” and “_L” indicate the “high” group and the “low” group, respectively. The socio-economic data involved in this table for the classification are measured in 2016 as the base year. Panels (A) to (F) reported the results for AQI, PM2.5, PM10, SO2, NO2, and CO, respectively
***Significant at 1%
**Significant at 5%
*Significant at 10%