Table 3.

Unit root test results

Variables	Constant				Order of Integration
	Level	p-value	1st difference	p-value
LNHS	−5.248***	0.000	−2.229*	0.066	I(0)
LNENC	−1.840	0.368	−3.272***	0.000	I(1)
LNCO2	−1.578	0.680	−3.381***	0.000	I(1)
LNPUH	−2.399**	0.020	−3.772***	0.000	I(0)
LNPVH	−2.047	0.165	−3.313***	0.000	I(1)
LNPERGDP	−1.374	0.863	−2.955***	0.000	I(1)
LNSAN	−3.189***	0.000	−2.335**	0.035	I(0)

Note: ^{***, **,} and ^* denote significance level at 1, 5 and 10%, respectively