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

Table 7

The summary of time factors of CO-based emission factors in China.

No.	Annual reduction rate (%)	Time span	Source	Reference
1	2	2000–2030	Current spec.	[10]
2	3.6	2010–2030	PIARC	[24]
3	2.4	2018–2035	PIARC	[13]
4	4.22	2000–2015 (gasoline-fuelled vehicle)	Manual for design	[34]
5	5.44	2000–2015 (diesel-fuelled vehicle)	Manual for design	[34]
6	3	1995-	Engineering application (such as Qingdao Jiaozhou bay subsea tunnel and connection subway)	[63]
7	34	2004–2011	Predicted results	This study
8	14.5	2011–2030
9	20.2	2004–2030
10	4.9–12.6	2000–2014	Backcalculated results	This study