1. ENAC-SSIE Laboratoire de Pollution de l'Air Model Strategies Simplify the equations Find an analytical solution Keep the equations Simplify the resolution

2. ENAC-SSIE Laboratoire de Pollution de l'Air Gaussian Model Wind speed Virtual Source Non reactive Pollutant Punctual Pollutant Source Constant Wind Homogenous Turbulence

3. ENAC-SSIE Laboratoire de Pollution de l'Air Gaussian Model with C pollutant concentration [gm -3 ], Q pollutant fluxes at the source [gs -1 ], U mean wind speed [ms -1 ],  y  standard deviation of the horizontal turbulent distribution [m],  z  standard deviation of the vertical turbulent distribution [m], H effective height of the pollutant source [m].

4. ENAC-SSIE Laboratoire de Pollution de l'Air Gaussian Model Pasquill classes for atmospheric stability

5. ENAC-SSIE Laboratoire de Pollution de l'Air Gaussian Model StabilityParameters (x in km) A T = 24.167 – 2.5335 ln x B C D E F T = 18.333 – 1.8096 ln x T = 12.5 – 1.0857 ln x T = 8.3333 – 0.72382 ln x T = 6.25 – 0.54287 ln x T = 4.1667 – 0.36191 ln x withx the distance to the pollutant source [km]

6. ENAC-SSIE Laboratoire de Pollution de l'Air Gaussian Model with x the distance to the pollutant source [km]

7. ENAC-SSIE Laboratoire de Pollution de l'Air Lagrangian Particles Model Concentration U  x=U  t  x=(U+u)  t U u Air parcel trajectories Additional turbulent wind speed

8. ENAC-SSIE Laboratoire de Pollution de l'Air Box Model Eulerian: fixed box Wind flow Lagrangian: moving box Wind flow: Box trajectory

9. ENAC-SSIE Laboratoire de Pollution de l'Air Moving column Wind flow: Column trajectory Lagrangian Column Model

10. ENAC-SSIE Laboratoire de Pollution de l'Air Eulerian 3D Model Eulerian 3D mesh

11. ENAC-SSIE Laboratoire de Pollution de l'Air Eulerian 3D Model xx i-1 i i+1 C 2/1i F  n i C 2/1i F  i S

12. ENAC-SSIE Laboratoire de Pollution de l'Air xx i-1 i i+1 n i C Eulerian 3D Model tt Time Distance n+1 i C Boundary Conditions B.C. Initial Conditions

13. ENAC-SSIE Laboratoire de Pollution de l'Air Eulerian 3D Model Exact solution after 5s Initial condition Exact solution

14. ENAC-SSIE Laboratoire de Pollution de l'Air Eulerian 3D Model with

15. ENAC-SSIE Laboratoire de Pollution de l'Air Initial condition Solution after 5s  t=0.5s  t=0.1s Eulerian 3D Model 1 st order and

16. ENAC-SSIE Laboratoire de Pollution de l'Air Eulerian 3D Model

17. ENAC-SSIE Laboratoire de Pollution de l'Air Eulerian 3D Model 1 st and 3 d order and 1 st order 3 d order Initial condition