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Comparative evaluation of an Comparative evaluation of an Eulerian Eulerian CFD and Gaussian plume models for CFD and Gaussian plume models for roadside heavy metal deposition roadside heavy metal deposition roadside heavy metal deposition


  1. Comparative evaluation of an Comparative evaluation of an Eulerian Eulerian CFD and Gaussian plume models for CFD and Gaussian plume models for roadside heavy metal deposition roadside heavy metal deposition roadside heavy metal deposition roadside heavy metal deposition Mohammad Taghavi 1 , Bertrand Carissimo 1 , Karine Sartelet 1 , Karine Muller 2 , Irène Korsakissok 1 1 Centre d’Enseignement et de Recherche sur l’Environnement Atmosphérique (CEREA), Joint Laboratory École des Ponts ParisTech / EDF R&D, Université Paris-Est, 6-8 Avenue Blaise Pascal, 77420, Champs sur Marne, France 2 CETE de Lyon, 46 rue Saint-Théobald, 38081, L'Isle d'Abeau cedex, France Corresponding author : taghavi@cerea.enpc.fr, Phone +33 164152145, Fax : +33 1 64 15 21 70

  2. outline outline • • Context Context and objectives and objectives • Tools and development Tools and development • Case study, Model configuration and Input data • Case study, Model configuration and Input data Case study, Model configuration and Input data Case study, Model configuration and Input data • Inter Inter-comparison between models, Results comparison between models, Results • Conclusions Conclusions Harmo13, Paris, France Harmo13, Paris, France

  3. Context Context and objectives and objectives � Road transport systems: Benefits and problems Benefits and problems + efficient and flexible, important role in world’s economy and human’s life quality. - Negative impact on air quality 21 toxic substances can mainly be assigned to road traffic. heavy metals are among them (e.g. Pb, Cd, Cu, Sb & Zn). Cadmium ranks 7th on U.S. EPA priority list of hazardous substances. In most European cities emission from road traffic has become the most important source of local air pollution. Harmo13, Paris, France Harmo13, Paris, France

  4. Context and objectives Context and objectives � Vehicular traffic emission contribution at regional scale Vehicular traffic emission contribution at regional scale Sector split emissions of primary and secondary fine particulates (Source: EEA) (EEA member countries; EU-15; EU-27 - EU-15; EFTA-4 and CC-3; efta-4 and CC-3 Synonyms: Iceland, Liechtenstein, Norway, Switzerland) Harmo13, Paris, France Harmo13, Paris, France

  5. Context Context and objectives and objectives � Air pollution at near roadside Air pollution at near roadside Near roadside Near roadside deposition deposition • non-point source of particle-associated metals • direct affection (populated area) • indirect affection (unpopulated area) In France (Source: USIRF) : ~ One million kilometers paved roads ~ Eleven thousand kilometers expressways Controls Policy Harmo13, Paris, France Harmo13, Paris, France

  6. Context and objectives Context and objectives � Approaches, and appropriates tools Approaches, and appropriates tools Measurements Valuable information about pollution levels Modeling Direct source - receptor relationship, Scenarios study Direct source - receptor relationship, Scenarios study Problem at local scale: Complex geometry (flow and turbulence are significantly affected by the presence of groups of buildings and thus are widely inhomogeneous and unsteady) Question: Which model is appropriate? Harmo13, Paris, France Harmo13, Paris, France

  7. Tools and development Tools and development � Mercure_Saturne Mercure_Saturne model model 2 Gaussian models: a- ADMS urban V2 (Carruthers et al., 1997) b- Polyphemus_Gaussien (Korsakissok et al., 2008) 1 CFD model: Mercure_Saturne • Adapted for atmospheric modeling • Taking into account complex geometries • Meshes with any type of cell (tetrahedral, hexahedral, prismaticpyramidal, polyhedral…) • Any type of grid structure (unstructured, block structured, hybrid, conforming or with hanging nodes…) • Gas and aerosol dispersion And we added dry and wet deposition scheme Harmo13, Paris, France Harmo13, Paris, France

  8. Tools and development Tools and development � Dry and wet deposition schemes Dry and wet deposition schemes ������������������������������ ����������������������������� ����������� ����������� ���������������� ��������� ������������������ ��������� ���������������� �������������� ���� �������� ���� �������������� ���� ����������������������������������� ����������������������������������� ������������������������ ������������������������ ����������������������������������� ����������������������������������� ������������������������ ������������������������ ������������������������ ������������������������ ������������������������������ ������������������������������ ������������������������ ������������������������ ������������������������� ������ ������������������������������ ������������������������������� ���������������������������������������� ������������������������������� ���������������������������������� ������������������� �����������!�������������������� ���������������������������" �������� �������������� �������������� #��������������������������� ��������� ���� ���� ������� Simplified dry deposition scheme Simplified wet deposition scheme Harmo13, Paris, France Harmo13, Paris, France

  9. Tools and development Tools and development � Variation of dry deposition rate according to the diameter of the particle Wind = 10 m/s n velocity (cm s -1 ) Deposition v this work Roustan (2005) Harmo13, Paris, France Harmo13, Paris, France

  10. Case study, M Case study, Model configuration and Input data odel configuration and Input data � Measurement campaign, study domain * Harmo13, Paris, France Harmo13, Paris, France

  11. Case study, M Case study, Model configuration and Input data odel configuration and Input data � Field of modeling, grid (b- structured grid) Resolution: X: 1m with increasing rate of 1.1 Y: 10 m (constant) Z: 0.6m with increasing rate of 1.1 40,000 calculations nodes Harmo13, Paris, France Harmo13, Paris, France

  12. Case study, M Case study, Model configuration and Input data odel configuration and Input data � Emission (Cadmium) Emission (Cadmium) Mass quantity, size distribution, median diameter Tires & brakes wear Data: Laboratory of Applied Thermodynamics (LAT) and the Transport Research Laboratory (TRL) Exhaust Modeling software: IMPACT ADEME (V2) Modeling software: IMPACT ADEME (V2) Result Exhaust Tires + Brakes Repartition (mg/km/j) (mg/km/j) 2,5<PM<10 15,66 0 16 % 1<PM<2,5 9,27 0 10 % PM<1 2,82 69,63 74 % Total 27,75 69,63 100% Harmo13, Paris, France Harmo13, Paris, France

  13. Case study, M Case study, Model configuration and Input data odel configuration and Input data � Emission Emission Median diameter for each mode: PM1 related to the traffic is characterized by 95% particles lower than 0,5 microns (Santamaria et al., 1990; Lonati et al., 2006) Shape and position of emission source For Mercure_Saturne: Homogenize concentration up to 1.5 m height at the boundary (inflow boundary condition) For Gaussian models: Point sources at 1 and 0.5 m height in the road center for ADMS and Polyphemus_Gaussian respectively Harmo13, Paris, France Harmo13, Paris, France

  14. Case study, M Case study, Model configuration and Input data odel configuration and Input data � Background values of Cadmium deposition (Spatial& temporal variation) regional scale, 2001 (Roustan, 2005) Time variation, 1996-98 (site 4) Total cadmium deposition rate (gr.km -1 .yr -1 ) Harmo13, Paris, France Harmo13, Paris, France

  15. Inter Inter-comparison with Gaussian models, Results comparison with Gaussian models, Results � February 3, 1997, weak dispersion (weak wind: 1m/s) Harmo13, Paris, France Harmo13, Paris, France

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