Effects of Urban Density and City Size on Haze Pollution in China: Spatial Regression Analysis Based on 253 Prefecture-Level Cities PM_2.5 Data

Table 1

Descriptive statistics of the variables used in this study.

Variables	Meaning	Unit	Obs	Mean	Min	Max	Std. Dev.
PM2.5	PM2.5 concentration	µg/m^3	253	46.569	14.80	86.100	14.259
PD	Urban density	person/km^2	253	3746.170	450.0	11602.00	2415.017
CitSize	City size	10,000 persons	253	119.920	7.720	2418.330	235.602
GreLevel	Greening level	m^2	253	14.294	6.860	37.490	4.036
RoadDen	Road density	km/km^2	253	8.758	1.346	70.298	7.916