Appendix 3.7b	Detailed Calculation of In-Tunnel Air Quality
	for the Full Enclosure at the slip road to Siu Lam Interchange
			-  Overall Concentrations
Four assessment points (ASRs P1b-P4b) at the boundary of the full enclosure are chosen (see Figure A3.1).
Using CALINE4 and ISCST3 model, the NO2 concentrations at the 4 assessment points at different levels are calculated
Sample Output file is shown in Appendix 3.8
The highest concentration among the four assessment points is assumed to be the background
NO2 concentration inside the full enclosure section.
		Elevation	NO2 Concentrations (ug/m3) at Various Levels
		(mAG)	P1b	P2b	P3b	P4b
		0	299	375	277	336
		2.75	277	323	262	322
		5.5	236	254	225	285
Therefore, the background concentration inside the full enclosure section is								375	ug/m3.
Overall Maximum NO2 concentration inside
the full enclosure section (Normal Speed)			=	375+60
			=	435	ug/m3
Overall Maximum NO2 concentration inside
the full enclosure section (Worse Case)			=	375+147
			=	522	ug/m3