“…Control variables: To capture the character of the city where a CNSA was located, several control variables, such as economic development ( x 1 , measured by per capita gross domestic product), consumption ( x 2 , measured by per capita retail sales of consumer goods), industrial structure upgrading ( x 3 , measured by the shares of tertiary industry in the local gross domestic product), infrastructure ( x 4 , measured by per capita urban road area), green rate ( x 5 , measured by the green coverage rate of built-up area), the air pollution of sulfur dioxide ( x 6 , measured by per capita emission of sulfur dioxide), the air pollution of dust ( x 7 , measured by per capita emission of dust), and the liquid pollution of wastewater ( x 8 , measured by per capita emission of wastewater), were employed by referring to the studies in [ 4 , 7 , 12 ].…”