Journal of Environmental and Public Health

Research Article

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

Table 1

The descriptive statistics for the model variables.


Variables	Obs.	Pilot city		Unpiloted city
Variables	Obs.	Mean	Std. dev.	Mean	Std. dev.

Air quality
(μg/ )	1610	64.06	23.22	51.01	20.47

Climate data
Average wind speed (m/s)	1610	2.23	0.59	1.93	0.92
Sunshine hours (h)	1610	5.75	1.26	4.94	1.37
Average air pressure (hPa)	1610	4.99	0.02	4.99	0.03

City characteristic data
The proportion of the secondary industry in GDP	1608	52.51	9.97	48.38	10.01
Industrial wastewater discharge (10 thousand tons)	1606	3.85	0.50	3.68	0.47
Industrial sulfur dioxide emissions (tons)	1604	4.74	0.44	4.48	0.52
Emissions of industrial smoke and dust (tons)	1602	4.37	0.41	4.11	0.50
Rate of comprehensive utilization of industrial solid waste	1588	82.18	39.59	80.95	19.76
Treatment rate of domestic sewage	1545	72.19	23.45	65.23	26.71
Rate of harmless treatment of domestic garbage	1530	88.18	20.10	79.85	26.73
Green coverage area in built-up areas (hectares)	1606	3.66	0.49	3.41	0.47
Actual foreign investment (10 thousand dollars)	1592	4.57	0.93	4.16	0.87
The total industrial output value of enterprises (10 thousand yuan)	1607	6.99	0.67	6.60	0.75
Number of urban unemployed registered (person)	1601	4.38	0.41	4.30	0.36
Population density (person/km²)	1491	2.64	0.35	2.54	0.37
Number of public automobiles and electric vehicles per 10,000 people	1609	9.91	12.25	7.85	9.77
Technology progress	1610	0.93	0.15	0.926	0.15
The proportion of the tertiary industry in GDP	1610	38.41	10.75	36.95	8.69
Industrial structure rationalization	1610	–4.98	86.89	–1.45	52.93
Energy consumption per unit of GDP (ton of standard coal/100 million yuan) (log)	1610	3.99	0.26	4.01	0.22

Source: the data on air quality originate from the world density map; the weather data come from the National Climatic Data Center; the China Energy Statistical Yearbook calculates energy consumption per unit of GDP; other city characteristic variables are from the Statistical Yearbook of Cities.