Building Better Cities: Evaluating the Effect of Circular Economy City Construction on Air Quality via a Quasi-Natural Experiment

Table 6

The results of the mechanism analysis.

Variables	Structure effect
	Air quality	Advancement of the industrial structure	Air quality	Industrial structure rationalization	Air quality
	(1)	(2)	(3)	(4)	(5)
		0.496	−1.615	−0.653	−1.833
	(0.599)	(0.405)	(0.863)	(0.996)	(0.234)
Advancement of the industrial structure			−0.026
			(0.108)
Industrial structure rationalization					−5.652
					(3.118)
_cons	−79.011	110.861	−76.105	−65.345	−49.545
	(81.352)	(36.390)	(86.305)	(41.236)	(56.921)
Weather control variables	Yes	Yes	Yes	Yes	Yes
City control variables	Yes	Yes	Yes	Yes	Yes
City-fixed effects	Yes	Yes	Yes	Yes	Yes
Year-fixed effects	Yes	Yes	Yes	Yes	Yes
Observation	1608	1608	1608	1608	1608
R ^2	0.457	0.849	0.457	0.029	0.011
Variables	Scale effect		Technology effect
	Energy consumption per unit of GDP	Air quality	Technological progress		Air quality
	(6)	(7)	(8)		(9)
	−0.044	−1.819	0.001		0.988
	(0.017)	(0.843)	(0.009)		(0.760)
Energy consumption per unit of GDP		−4.310
		(2.394)
Technological progress					3.622
					(1.543)
_cons	4.047	−61.572	56.345		39.298
	(1.692)	(85.531)	(35.451)		(51.332)
Weather control variables	Yes	Yes	Yes		Yes
City control variables	Yes	Yes	Yes		Yes
City-fixed effects	Yes	Yes	Yes		Yes
Year-fixed effects	Yes	Yes	Yes		Yes
Observation	1608	1608	1608		1608
R ^2	0.756	0.459	0.122		0.168

Note: (1) The control variables are the same as the benchmark regression equation. (2) The symbols , , and represent a significance level of 10%, 5%, and 1%, respectively.