Table 2 Robustness test of the environmental effects of HSR on SO2 emission reduction.
From: The impact of high-speed rail on SO2 emissions—based on spatial difference-in-differences analysis
Variables | Change the sample period | Bilateral censoring at the 1% level | Placebo test | Change explanatory variable | Change spatial matrix |
|---|---|---|---|---|---|
SO2 | |||||
(1) | (2) | (3) | (4) | (5) | |
HSR | − 0.101* | − 0.078** | − 0.120*** | ||
(0.057) | (0.036) | (0.041) | |||
HSR_fault | − 0.008 | ||||
(0.027) | |||||
HSR_station | − 0.008* | ||||
(0.005) | |||||
W*HSR | − 0.460* | − 0.877*** | 0.462 | − 0.327*** | − 1.215*** |
(0.272) | (0.159) | (0.295) | (0.046) | (0.328) | |
rho | 0.586*** | 0.582*** | 0.324*** | 0.563*** | 0.814*** |
(0.070) | (0.053) | (0.085) | (0.057) | (0.049) | |
LR_Direct | |||||
HSR | − 0.106* | − 0.090** | 0.007 | − 0.012* | − 0.151*** |
(0.059) | (0.037) | (0.027) | (0.007) | (0.044) | |
LR_Indirect | |||||
HSR | − 1.269* | − 2.219*** | − 0.344 | − 0.762*** | − 7.645** |
(0.771) | (0.509) | (0.302) | (0.141) | (3.605) | |
LR_Total | |||||
HSR | − 1.375* | − 2.309*** | − 0.336 | − 0.774*** | − 7.796** |
(0.777) | (0.514) | (0.302) | (0.143) | (3.618) | |
R-squared | 0.266 | 0.150 | 0.080 | 0.245 | 0.118 |
Control variables | YES | YES | YES | YES | YES |
Time Fixed | YES | YES | YES | YES | YES |
City Fixed | YES | YES | YES | YES | YES |
N | 1995 | 3135 | 3135 | 3135 | 3135 |
