Formation and dispersion of secondary inorganic aerosols

by high ammonia emissions

Eberhard Renner, Ralf Wolke

Leibniz Institute for Tropospheric Research, Leipzigrenner@tropos.de

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.

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Niederschlag

Zur Anzeige wird der QuickTime™ Dekompressor „Microsoft Video 1“

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Zur Anzeige wird der QuickTime™ Dekompressor „Microsoft Video 1“

benötigt.

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!