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Formation and dispersion of secondary inorganic aerosols
by high ammonia emissions
Eberhard Renner, Ralf Wolke
Leibniz Institute for Tropospheric Research, [email protected]
GLOREAMParis, Oct. 2006
OUTLINE
MOTIVATION
MODELLING APPROACH
SOME RESULTS
SUMMERY
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.
In this study the contribution of ammonia emissions especially from agriculture and livestock husbandry to the formation of inorganic secondary particles (PM2.5 and PM10)
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.
CTMParallel MUSCAT
EmissionsLanduse Data
Meteorology:Parallel LM
Gasphase Chemistry
RACMAerosoldynamics
„EMEP“
Post-Processing
online data-file
MODELLING APPROACH
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 SO2, NOx, CO, NH3, PM2.5, PM10, methane, and non-methane volatile organic compounds (NMVOC).
5% of SO2 are emitted directly as sulfate.
The TNO/UBA emission data were used, with a resolution of 15x15km for the European Region.
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.).
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
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)
AEROSOL MODEL The study is focused mainly of secondary inorganic particles with sizes below 10 μm (PM10).
The dominant contribution to mass increasing is caused by the heterogeneous condensationof gaseous compounds on pre-existing aerosols.
Ammonia and sulfuric/nitric acid, generated by several paths from the precursory species SO2 and NOx, are involved.
NH3
reaction (day/night)
NOx
reaction(gas-/aqueous-
phase)
SO2
e m i t t e d g a s e o u s p o l l u t a n t s
P M 1 0
p r i m a r y s e c o n d a r y
PPM10Sulfate-
ionsAmmonium-
nitrateAmmonium-
sulfate
fast, irreversible reaction
variableequilibrium
condensation
HNO3 SO42-
emission
5 %
Refinement factor is 2;
Refinement level
between neighbouring
blocks is restricted to 1; No overlapping blocks; Mass-conservation is
saved !!
Decomposition of Horizontal DomainStatic grid in a “multiblock approach“
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
Parallelizationdomain decomposition, load-balancing
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
Coupling Scheme new approach for SAMUM
Feedback
Feedback of dust to radiation!
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.
0
90
180
270
360
Zeit (Tage)
Win
dri
chtu
ng
[]
0,00
1,00
2,00
3,00
4,00
5,00
6,00
7,00
8,00
9,00
10,00
Nie
de
rsch
lag
[mm
]
Windrichtung
Niederschlag
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SUMMERY The formation of mass of secondary inorganic
particles (PM10) was examined in a region of higher ammonina emissons.
More than 50% of the simulated PM10-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!