1. Formation and dispersion of secondary inorganic aerosols by high ammonia emissions Eberhard Renner, Ralf Wolke Leibniz Institute for Tropospheric Research, Leipzig renner@tropos.de GLOREAM Paris, Oct. 2006

2. OUTLINE  MOTIVATION  MODELLING APPROACH  SOME RESULTS  SUMMERY

3. MOTIVATION  Fine and ultra-fine particles are increasingly suspected to cause damages in human health and natural environment.  Besides the reduction of primary emissions by traffic, industry, agriculture and other sources, currently the focus of environmental sciences and politics is directed also at the formation of secondary particles.

4.  In this study the contribution of ammonia emissions especially from agriculture and livestock husbandry to the formation of inorganic secondary particles (PM 2.5 and PM 10 ) in a regional scale for longer time periods will be examined.  The modelling work is part of the project AMMONISAX, a measuring project, to compare different measuring methods for ammonia, funded by the German Federal State Niedersachsen.

5. CTM Parallel MUSCAT Emissions Landuse Data Meteorology: Parallel LM Gasphase Chemistry RACM Aerosoldynamics „EMEP“ Post-Processing onlinedata-file MODELLING APPROACH

6. ANTHROPGENIC EMISSIONS  10 SNAP codes of EMEP/CORINAIR for characterising the different anthropogenic source types (e.g., combustion in energy industry, road transport, agriculture) are used.  The considered chemical species are the main pollutants SO 2, NO x, CO, NH 3, PM 2.5, PM 10, methane, and non-methane volatile organic compounds (NMVOC).  5% of SO 2 are emitted directly as sulfate.  The TNO/UBA emission data were used, with a resolution of 15x15km for the European Region.

7. BIOGENIC EMISSIONS  The NO emissions are calculated in dependence on the vegetation type and surface temperature (Williams et al.).  The VOC emissions additionally depend on sunlight (Günther et al.).

8. METEOROLOGICAL MODEL  LM (Local Model) of German Weather Service  non-hydrostatic  operational mode for weather forcast  regional scale  boundary and initial data from GME  highly parallel

9. CHEMISTRY-TRANSPORT-MODEL  MUSCAT (Multi-Scale Atmospheric Transport Model)  The transport processes include advection, turbulent diffusion, dry and wet deposition and sedimentation  Gas phase mechanism RACM  Aerosol model:mass-based scheme (similar to the EMEP model)

10. AEROSOL MODEL  The study is focused mainly of secondary inorganic particles with sizes below 10 μm (PM 10 ).  The dominant contribution to mass increasing is caused by the heterogeneous condensation of gaseous compounds on pre-existing aerosols.  Ammonia and sulfuric/nitric acid, generated by several paths from the precursory species SO 2 and NO x, are involved.

11. 5 %

12.  Refinement factor is 2;  Refinement level between neighbouring blocks is restricted to 1;  No overlapping blocks;  Mass-conservation is saved !! Decomposition of Horizontal Domain Static grid in a “multiblock approach“

14. NUMERICAL METHODS  Space discretization  Staggered grid. Finite-volume techniques  Advection: Third-order upwind scheme (Hundsdorfer et al.,1995)  Time-integration: IMEX scheme  Explicit second-order Runge-Kutta for horizontal advection  Second order BDF method for the rest: Jacobian is calculated explicitly, linear systems by Gauss-Seidel iterations or AMF  Automatic step size control  Parallelization domain decomposition, load-balancing

15. Coupling Scheme  Time interpolation of the meteorological fields: 1. Linear interpolated in [tn,tn+1]: Temperature, Density,…. 2. Time-averaged values on [tn,tn+1]: Projected wind field, necessary for mass conservation !!  Separate time step size control for LM and MUSCAT

16. Coupling Scheme new approach for SAMUM Feedback  Feedback of dust to radiation!

19. RESULTS  Results are shown for May 2006. At the beginning of the month it was a high pressure period with moderate winds from East. The second half was a period with stronger winds from West.

40. SUMMERY  The formation of mass of secondary inorganic particles (PM 10 ) was examined in a region of higher ammonina emissons.  More than 50% of the simulated PM 10 -mass were secondary formatted ammonia sulfate and ammonia nitrate.  The fraction of ammonia nitrate was extrem dependent from the meteorological conditions.  It seems to exists a significant deficiency in primary emitted particles, especially by easterly winds!