Bedogni M. , Costa M.P., Casadei S. AMA Mobility and Environment Agency of Milan, Milan, Italy

1. AMA - MI Comparison and validation of long term simulation of PM10 over 7 European cities in the frame of Citydelta project Bedogni M. , Costa M.P., Casadei S. AMA Mobility and Environment Agency of Milan, Milan, Italy Pirovano G. CESI RICERCA Spa, Milan, Italy

2. http://aqm.jrc.it/citydelta/ Phase III

3. CAMx version 4.21 • Horizontal advection:Bott Scheme • Resistance Based Dry Deposition • Wet Deposition • Photolysis rates adjusted as a function of cloud cover, total ozone column and turbidity • Gas phase chemistry • Mechanism: CBIV99 Solver: CMC • Aerosol phase chemistry • SIA: Isorropia SOA: SOAP algorithm • Coarse/Fine bins No dynamic processes

4. Introduction... Vautard R. et al., Evaluation and intercomparison of Ozone and PM10 simulations by several chemistry-transport models over 4 european cities within the City-Delta project, Atm. Env., 2006, in press. City-delta III • Base year 2004 • Only CAMx model • 5+2 cities: Berlin, Lisbon, London, Milan, Paris, (Prague, Krakow) • MM5 meterological fields at 10 km (Milan 5km, Lisbon 2km) • Kv computation following CMAQ approach • EMEP Emission Inventory & local inventories spatial distribution • Biogenic emissions • CHIMERE continental fields as B.C. • No specific tuning for each city ...We may look at this exercise with...

5. …a “synoptic” point view …in order to discuss a couple of interesting topics • Operational evaluation of the modelling system • PM10 mass and composition

6. NOX Emission density Distance from city centre Stations subsets

7. Yearly Mean CAMx Obs O3 (8h daytime r.a. - summer) NO2 (24h r.a.) Ox (24h r.a.) PM10 (24h r.a.)

8. BIAS O3 NO2 PM10

9. Sigma ratio O3 NO2 PM10

10. Correlation O3 NO2 PM10

11. Time series - NO2 daily mean (city average) Milan Obs CAMx Lisbon Paris

12. Time series - O3 daily max (city average) Milan Obs CAMx Lisbon Paris

13. Time series - PM10daily mean (city average) Milan Obs CAMx Lisbon Paris

14. PM10 - total mass (yearly mean) PM10 SIA PPM10

15. PM10 - relative composition City centre Urban areas

16. NH3/NOX ratio (Domain Emix density) PM10 - concentrations vs emissions Par Primary PM10 (urban area) vs Urban area Emix density Mil Lis Mil Lon Nitrate (urban area) vs Domain Emix density (NOX ) Lis

17. Critical episodes - January 2004 Milan Urban area City centre Paris

18. Conclusions • Good reliability of emission inventories • Heterogeneous measured data set can mask model discrepancies • Photochemistry is well reproduced (also in Milan) at domain scale • Local scale effects on NO2/O3 induce BIAS of 5-15% • Performances for PM10 are less reliable and more heterogeneous: • 10-20 % of mass is missing and variability is not well described • Fine scale meteorology has clearly enhanced model performances • PM10 yearly mean is around 20 [mg/m3] (…not in Milan!) • Milan: combined effect of low ventilation and chemistry on PM10 • Lisbon: ….a particular case… • Sever episodes: errors may be emphasised (critical for exceedances)

19. CAMx Next steps... • Evaluation of critical episodes (exceedances) • Having established several datasets, we are planning to: • perform source-apportionment analysis (OSAT & PSAT) • perform systematic sensitivity analysis (PA & DDM) • Following the “spirit” of Citydelta and the ACCENT network we are surely interested and willing to join projects based on model ensemble approach

20. Thanks to… The authors would like to thank CONCAWE (London), IIASA (Vienna) and JRC (Ispra) to have funded and promoted the phase III of Citydelta modelling exercise. The authors would also like to thank Claudio Carnevale of the University of Brescia for his valuable contribution in the development of the emission processor, TERRARIA (Milan) to have provided biogenic emissions, and ARPA Lombardia to have performed some simulations . Mobility and Environment Agency technical contribution has been sustained by the Municipality of Milan. guido.pirovano@cesiricerca.it

21. Paris Stations PM10 NO2