Emission Reduction Effect and Mechanism of Auto-Purchase Tax Preference

Table 1

Variable definition.

Variable	Definition
LnSO2	Logarithm of city SO2 emissions
LnWater	Logarithm of city wastewater emissions
LnSoot	Logarithm of city soot emissions
Time	Equal to 1 if the year is after 2015, 0 otherwise
Post	Equal to 1 if the time is after December 2015, 0 otherwise
Treat	Equal to 1 if the displacement is less than 1.6 L, 0 otherwise
LnGDP	Logarithm of city GDP
LnPop	Logarithm of city population
Pollution_Degree	Degree of city pollution. The ratio of secondary industry GDP to total industry GDP
LnUrban	Logarithm of urbanization rate
LnMile	Number of road miles by province
LnIncome	Disposable income per capita by province
LnOil_Price	International crude oil prices
Price_Grade	Car price class. For every 50,000 RMB increase in price, the car goes up one level