Table 1 Descriptive statistics.
From: The spatial spillover effect of higher SO2 emission tax rates on PM2.5 concentration in China
Variable | Indicator | Number of Obs | Mean Value | Std. Dev | Max | Min | Unit | Role and references |
|---|---|---|---|---|---|---|---|---|
PM | PM2.5 concentration (van Donkelaar et al., 2021) | 4560 | 45.313 | 15.285 | 108.634 | 13.454 | μg/m3 | Interpreted variable (van Donkelaar et al.23) |
POST | Dummy variable for discharge tax reform | 4560 | 0.310 | 0.462 | 1.000 | 0.000 | – | Components of the main explanatory variable (i.e., the DID term, Jia et al.20) |
FSDIOX | Real tax rate on SO2 emission | 4560 | 0.735 | 0.717 | 7.646 | 0.188 | Yuan / Kg | |
GDPPC | Per capita real GDP | 4560 | 16,970.941 | 12,543.812 | 92,522.068 | 1283.188 | Yuan/people | Control the impact of social and economic development levels on air pollution (Dietz and Rosa25) |
POPUD | Population density | 4560 | 3661.339 | 2822.769 | 27,203.060 | 27.000 | People/Km2 | |
RDEMP | Proportion of R & D employees in population | 4560 | 0.178 | 0.236 | 2.784 | 0.009 | % | |
ROAD | Road area per capita | 4560 | 36,873.451 | 33,569.976 | 359,608.498 | 376.770 | m2/people | Control the impact of the infrastructure of transportation and energy on air pollution (Liu et al.28; Zhang and Wang29) |
GASR | Gas penetration rate | 4560 | 22.411 | 18.199 | 100.000 | 0.483 | % | |
NDVI | Vegetation index | 4560 | 72.595 | 13.450 | 89.545 | 9.689 | % | Control the inhibition and absorption of vegetation on PM2.5 (Liu et al.28) |
PRSD | Annual mean atmospheric pressure | 4560 | 957.914 | 62.922 | 1016.810 | 693.283 | Hpa | Control the impact of meteorological factors on PM2.5 pollution (Liu et al.30; Liu et al.28; Yan et al.16) |
TEMP | Annual mean temperature (absolute temperature) | 4560 | 286.984 | 5.182 | 298.902 | 271.941 | Degree | |
WIN | Annual mean wind speed | 4560 | 2.129 | 0.416 | 3.658 | 1.047 | m/s | |
RHU | Annual mean relative humidity | 4560 | 65.650 | 9.944 | 80.083 | 32.119 | % |
