1. B. Carissimo, S. Lacour, H. Foudhil,L. Musson-Genon, E. Dupont, M. Milliez, B. Albriet, E. Demael, L. Laporte, Tunnel modelling : the collaboration with the CETU Atmospheric CFD modelling for environmental applications at local scale,

2. History CETU: ventilation and environment team Technical service of the Equipment Ministry Defining state of art, methods for studying tunnels Conception of fire protection system Environmental studies around tunnels Collaboration with the CEREA started in 2002

3. Modelling tools Polair3D local: RACM chemistry Eulerian advection diffusion scheme Reactive plume/box models Street model, OSPM … Mercure_Saturne reactive version

4. Dispersion around a tunnel portal Vehicle induces flows in a non-ventilated tunnel. HVG passing produced a high frequency signal on flow velocity Tunnel also filters vehicle drag effect and produced low frequency variations on the flow velocity

5. Dispersion around a tunnel portal Pollutant escape occurs earlier in the street in the case of unsteady flows Advection effects were found greater than turbulent ones. Street concentration decrease is lower than 30% in unsteady cases Lacour and al., UAQ 2003

6. Dispersion around a tunnel portal Street NO2 concentration increases From 0% when the primary background pollution is high Up to 100 % in case of ozone peaks Ozone availability is a limitation factor for NO conversion near the exit

7. Dispersion around a tunnel portal Statistical analysis were made for 2 different urban aeras Reactive models (OPSM1, OSPM2, TNO, Street) were compared Dilution factors were established for NO2 reactive dispersion around tunnel portal Guide méthodologique « Etude d’environnement » CETU 2005

8. Dispersion around a tunnel portal

9. Building affects plume geometry in this campaign The validation of the CEREA model, developed for flat terrain, is not possible with these measurements.

10. Dispersion around a tunnel portal NO2 concentration field wind Reactive NO2 model was used to study depollution effectiveness of catalytic walls. A measurement campaign would be carried out by the CETE of Lille around a tunnel portal in Paris and used for validation purposes