Table 2 Estimation results.
From: The spatial spillover effect of higher SO2 emission tax rates on PM2.5 concentration in China
Variables | Robustness tests | Heterogeneity analysis | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Model A | Model B | Model C | Model D | Model E | Model F | Model G | Model H | Model I | Model J | Model K | |
Base-line Model | PSM-Spatial-DID | Spatial-DID-2SLS Model | Spatial weight matrix: We | Interpreted variable: PMCH | Interpreted variable: PME | Eastern cities (EAST) | Administrative level (CLEVEL) | Pilot cities of emission rights trading (PET) | Key regions of APPCAP (PCAP) | NOx emission tax rate reform (REFNF) | |
POST × FSDIOX | − 0.039*** | − 0.047*** | − 0.02** | − 0.024*** | − 0.033*** | − 0.117*** | − 0.049*** | − 0.02** | − 0.032*** | − 0.025*** | − 0.034*** |
(− 6.451) | (− 8.33) | (− 2.33) | (-4.786) | (− 7.716) | (− 8.266) | (− 4.661) | (− 2.09) | (− 4.294) | (− 3.453) | (− 3.563) | |
W × POST × FSDIOX | 0.119*** | 0.148*** | 0.022 | 0.216*** | 0.106*** | 0.290*** | 0.184*** | 0.34*** | 0.15*** | 0.110*** | 0.144*** |
(4.225) | (5.648) | (0.64) | (3.063) | (5.211) | (4.504) | (3.295) | (3.164) | (3.594) | (2.933) | (3.104) | |
W × PM (Interpreted Variable) | 0.981*** | 0.977*** | 2.09*** | − 0.075 | – | – | 0.981*** | 0.984*** | 0.983*** | 0.983*** | 0.981*** |
(304.057) | (244.672) | (19.54) | (–0.797) | – | – | (304.331) | (361.466) | (340.950) | (339.768) | (303.862) | |
W × PMCH (Interpreted Variable) | – | – | – | – | 0.986*** | – | – | – | – | – | – |
– | – | – | – | (411.608) | – | – | – | – | – | – | |
W × PME (Interpreted Variable) | – | – | – | – | – | 0.928*** | – | – | – | – | – |
– | – | – | – | – | (79.313) | – | – | – | – | – | |
Control Variables | Controlled | Controlled | Controlled | Controlled | Controlled | Controlled | Controlled | Controlled | Controlled | Controlled | Controlled |
– | |||||||||||
D.E._POST × FSDIOX | − 0.024*** | − 0.030*** | − 0.019** | − 0.024*** | − 0.014*** | − 0.109*** | − 0.022** | 0.062** | − 0.005 | − 0.010** | − 0.016** |
(− 4.024) | (− 6.091) | (− 2.257) | (− 4.882) | (− 2.717) | (− 9.713) | (− 1.990) | (2.387) | (− 0.629) | (− 2.393) | (− 2.133) | |
I.E._ POST × FSDIOX | 4.505*** | 4.449*** | 0.029** | 0.204*** | 5.411*** | 2.737*** | 8.496*** | 22.932*** | 7.534*** | 5.044*** | 5.776*** |
(2.899) | (3.731) | (2.093) | (2.917) | (3.092) | (2.912) | (3.292) | (3.238) | (3.399) | (2.756) | (3.297) | |
D.E._POST × FSDIOX × EAST | - | - | – | – | – | – | 0.001 | – | – | – | – |
– | – | – | – | – | – | (0.083) | – | – | – | – | |
I.E._POST × FSDIOX × EAST | – | – | – | – | – | – | − 5.309** | – | – | – | – |
– | – | – | – | – | – | (− 2.053) | – | – | – | – | |
D.E._POST × FSDIOX × CLEVEL | – | – | – | – | – | – | – | − 0.069*** | – | – | – |
– | – | – | – | – | – | – | (− 3.424) | – | – | – | |
I.E._POST × FSDIOX × CLEVEL | – | – | – | – | – | – | – | − 15.264*** | – | – | – |
– | – | – | – | – | – | – | (− 2.735) | – | – | – | |
D.E._POST × FSDIOX × PET | – | – | – | – | – | – | – | – | − 0.036*** | – | – |
– | – | – | – | – | – | – | – | (− 3.102) | – | – | |
D.E._POST × FSDIOX × PET | – | – | – | – | – | – | – | – | − 0.036*** | – | – |
– | – | – | – | – | – | – | – | (− 3.102) | – | – | |
I.E._POST × FSDIOX × PCAP | – | – | – | – | – | – | – | – | – | − 0.043*** | – |
– | – | – | – | – | – | – | – | – | (− 4.142) | – | |
I.E._POST × FSDIOX × PCAP | – | – | – | – | – | – | – | – | – | − 3.209 | – |
– | – | – | – | – | – | – | – | – | (− 0.817) | – | |
I.E._POST × FSDIOX × REFNF | – | – | – | – | – | – | – | – | – | – | − 0.010 |
– | – | – | – | – | – | – | – | – | – | (− 1.397) | |
I.E._POST × FSDIOX × REFNF | – | – | – | – | – | – | – | – | – | – | − 1.703* |
– | – | – | – | – | – | – | – | – | – | (− 1.851) | |
– | – | – | – | – | – | – | – | – | – | ||
Observations | 4560 | 3936 | 4560 | 4560 | 4560 | 4275 | 4560 | 4560 | 4560 | 4560 | 4560 |
Number of cities | 285 | 246 | 285 | 285 | 285 | 285 | 285 | 285 | 285 | 285 | 285 |
R2 | 0.9736 | 0.9768 | 0.9736 | 0.9597 | 0.9858 | 0.9854 | 0.9736 | 0.9737 | 0.9736 | 0.9737 | 0.9736 |
Wald spatial lag test | 401.585*** | 193.251*** | 100.208*** | 555.096*** | 215.846*** | 410.056*** | 400.756*** | 401.969*** | 404.417*** | 401.822*** | 394.278*** |
LR spatial lag test | 407.764*** | 201.067*** | 407.764*** | 561.502*** | 224.662*** | 417.219*** | 406.938*** | 409.178*** | 411.546*** | 408.468*** | 400.686*** |
Wald spatial error test | 451.871*** | 224.211*** | 109.747*** | 558.045*** | 263.812*** | 413.476*** | 451.17*** | 455.437*** | 456.579*** | 454.439*** | 446.576*** |
LR spatial error test | 455.728*** | 232.09*** | 455.728*** | 559.485*** | 271.616*** | 417.575*** | 454.801*** | 459.925*** | 460.666*** | 459.435*** | 451.002*** |
LR spatial fixed effects test | 11,108.394*** | 10,086.787*** | 10,088.703*** | 11,108.394*** | 13,335.203*** | 14,624.605*** | 11,105.64*** | 11,116.038*** | 11,111.6*** | 11,126.816*** | 11,055.903*** |
LR time fixed effects test | 3186.68*** | 3242.986*** | 1578.417*** | 3186.680*** | 6688.258*** | 1615.188*** | 3189.912*** | 3194.548*** | 3173.147*** | 3194.900*** | 3183.774*** |
