Investigation on the Time Factor of CO-Based Emission Factors for Sustainable Development of Urban Tunnels in China

Table 5

The backcalculated CO-based emission factors for different base years (60 km/h).

Tunnel	Specified value of 2000	Left bore			Right bore
		2014	2000	Ratio of backcalculated value to specified value in 2000 (%)	2014	2000	Ratio of backcalculated value to specified value in 2000 (%)
Henglong Mountain Tunnel	0.007	0.0020	0.0027	39	0.0013	0.0017	25
Cejiexian Subway	0.007	0.0011	0.0014	20	0.0012	0.0016	23
Jiuweiling Tunnel	0.007	0.0034	0.0046	65	0.0030	0.0039	56
Dameisha Tunnel	0.007	0.0023	0.0031	44	0.0022	0.0030	42