Appendix 3.7	Detailed Calculation of In-Tunnel Air Quality
	for the Full Enclosure at Castle Peak Road viaduct
			-  Overall Concentrations
Four assessment points (ASRs P1a-P4a) 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)	P1a	P2a	P3a	P4a
		0	212	190	330	349
		2.75	238	201	317	327
		5.5	239	192	275	279
Therefore, the background concentration inside the full enclosure section is								349	ug/m3.
Overall Maximum NO2 concentration inside
the full enclosure section (Normal Speed)			=	349+84
			=	433	ug/m3
Overall Maximum NO2 concentration inside
the full enclosure section (Worse Case)			=	349+313
			=	662	ug/m3