Appendix
3.5 |
Calculations
of NO2 Concentration inside the Two Sections |
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of Deckover on Road D1 |
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Section
between Area 138L/M |
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Worse case |
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and Area 76 R1 Site |
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Tunnel Parameter |
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Tunnel
length (m), L |
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= |
190 |
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Tunnel height (m), H |
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= |
10 |
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Tunnel
width (m), W |
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= |
22 |
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Tunnel size (m2), At |
= |
H * W |
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220 |
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Equivalent diameter (m), dt |
= |
(4*At/p)^0.5 |
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16.73657 |
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Effective length of the
tunnel (m), Le |
= |
L + 2*3*dt |
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290.4194 |
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Emission Data |
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Traffic Breakdown (%) |
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Traffic flow (veh/hr) |
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P/C |
Taxi |
Bus |
LGV |
HGV |
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Tunnel traffic |
4800 |
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51 |
18 |
4 |
9 |
18 |
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Q (veh/hr) |
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2448 |
864 |
192 |
432 |
864 |
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P/C |
Taxi |
Bus |
LGV |
HGV |
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Emission
Factor (g/km) - EURO3 |
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0.71 |
0.73 |
6.8 |
1.23 |
3.84 |
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Weighted
NOX E.F. (g/km/veh) |
= |
1.5674 |
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NO2
emission factor per unit length (g/m/s), w |
= |
0.000418 |
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Vehicle Data |
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Nominal
dimensions of vehicles are given in Transport Planning and Design Manual,
Vol. 2 as: |
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W |
H |
L |
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Cars and Taxi |
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1.7 |
1.5 |
4.6 |
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Bus |
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2.5 |
4.6 |
12 |
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LGV |
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2.1 |
1.6 |
5.2 |
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HGV |
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2.5 |
4.6 |
16 |
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Nominal cross-sectional area (m2) |
= |
(1.7*1.5*(0.51+0.18))+(2.5*4.6*0.04)+(2.1*1.6*0.09)+(2.5*4.6*0.18) |
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= |
4.5919 |
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Number of
lanes per direction, nl |
= |
2 |
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Equivalent
cross-sectional area for each direction (m2), Av |
= |
9.1838 |
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Equivalent
diameter of vehicle (m), dv |
= |
(4*Av/p)^0.5 |
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= |
3.41953 |
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Equivalent
length of each vehicle (m) |
= |
(4.6*(0.51+0.18))+(12*0.04)+(5.2*0.09)+(16*0.18) |
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= |
7.002 |
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Distance
between vehicle (m) |
= |
1 |
(worst case) |
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Head to
head distance on a lane (m), l |
= |
8.002 |
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Traffic
density (traffic flow /s), N |
= |
1.333333 |
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Average
vehicle speed (m/s), v |
= |
l*N/(2*nl) |
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= |
2.667333 |
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Diffusion
Parameters |
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Reynolds
number, Re |
= |
(v*dv)/s |
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where s = 15.6*10^-6 |
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= |
584681.2 |
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According
to Figure 16 (Ohashi and Koso) |
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Since |
l / dt |
= |
0.478115 |
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D / (N * dt^2 * Re^0.13) |
= |
0.13 |
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Longitudinal |
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diffusion
coefficient (m2/s) , D |
= |
0.13
* (N * dt^2 * Re^0.13) |
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= |
272.8442 |
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Maximum
Concentration of NO2 |
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Cmax (µg/m3) |
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= |
w * Le^2 / (8 * D * At) |
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(without background) |
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= |
73.41293 |
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