Title Progress in the development and results of the UNIFIED EMEP model Presented by Leonor Tarrason...

TitleProgress in the development and results of the UNIFIED

EMEP model

Presented by Leonor TarrasonEMEP/MSC-W

29th TFIAM meeting, Amiens, France, 10-12 May 2004

Outline

Meteorologisk Institutt met.no

• TFMM workshop REVIEW OF THE UNIFIED EMEP MODEL

• Progress at MSC-W in modelling PM mass

• PM emission speciation

• Water bound PM mass

• SOA empirical approaches to SOA modelling

• Meteorological variability and consequences for SR calculations

Evaluation of the EMEP model Mandate


Examination of the processes and meteorological parameterizations, chemical mechanisms and the sources of model input data; and

Evaluation of the model performance against daily observations of key model species and fluxes from the EMEP, AIRBASE and national monitoring networks for 1980, 1985, 1990, 1995, 1997, 1998, 1999 and 2000; and

A consideration of the source-receptor relationships for sulphur, nitrogen, ozone and suspended particulate matter (PM mass).

TFMM workshop to review and evaluate the Unified EMEP model was hold in Oslo 3-5 november 2003, with 72 participants, 2 European model inter-comparisons (TNO-EMEP, EURODELTA), individual country reviews

Evaluation of the EMEP model Conclusions O3


For ozone, it was concluded that the model:

is suitable for the assessment of vegetation exposure and for the assessment of human health effects on the regional scale with the aim to support European air quality strategies.

is suitable for the establishment of source-receptor data for human health exposure and vegetation exposure/uptake of ozone on the regional scale.

is able to predict changes in ozone concentrations caused by changes in precursor emissions on a European level.

“The model showed an excellent level of performance for daily maximum ozone concentrations. For nitrogen dioxide, the performance was less good, in common with all other models, possibly due to subgrid variations. The model shows a tendency to underestimate the episodic ozone peak concentrations (>60ppb) and uncertainties will be higher for source-receptor compared with extreme value statistics”

Evaluation of the EMEP model Conclusions O3


Long-term work plan recommendations:

Further consideration should be given to:

• interactions with local scale air pollution (particularly concerning the outcome of the CITY-DELTA exercise)

• the continued increase in background ozone concentrations for the assessment of trends

• the model and measured trends in VOCs and oxidation products and

• to developing improved partitioning of stomatal and non-stomatal fluxes of ozone to vegetation, validated against field observations.

Evaluation of the EMEP model Conclusions PM


For suspended particulate matter, it was concluded that the model:

in its present form significantly underestimates total PM concentrations due to unknown processes and emissions.

is however able to calculate the regional component of main anthropogenic PM fractions (sulphate, nitrate, ammonium, some primary components) with enough accuracy for the assessment of the outcome of different control measures.

requires urgent attention with the aim of developing the model further for the full assessment of the anthropogenic fraction of PM2.5.

Evaluation of the EMEP model Conclusions PM


Short term recommendations:In the short term, attention should be given to:

• the evaluation of present emission inventories

• the analysis of measurements and anthropogenic emissions of specific species of PM and the contribution to particle mass from particle-bound water

• the exploration of empirical approaches to the development of a model for secondary organic aerosol formation based on available data and knowledge.

Long-term recommendations: In the longer term, evaluations are required against speciated monitoring data,

the inclusion of improved emission inventories, the inclusion of biogenic primary emissions, the formation of secondary biogenic aerosols in order to achieve full mass closure.


Progress at MSC-W modelling PM mass

still plenty of uncertainties …..

PM EmissionsChemical speciation and size distribution of PM Emissions on-going work at PM Expert Group under TFEIP


PM2.5OC (%) EC (%) Mineral dust (%)

Power generation 33 33 33

Residential and other combustion 50 20 30

Industrial combustion 33 33 33

Production processes 0 20 80

Extraction & distribution of fossil fuels 40 50 10

Solvent and other product use 40 20 40

Road transport 40 20 40

Other mobile sources and machinery 40 20 40

Waste treatment and disposal 10 60 30

Agriculture 70 0 30

Size distribution (Aitken/accum) 15 / 85 (20 / 80) 15 / 85 (20 / 80) 0 / 100

Coarse PM = PM10 - PM2.5- - 100

Density, (kg/m3) 2000 2000 2600

Diameter 0.05/0.3 µm (0.02/ 0.2)µm 5 (6.5) µm


Daily PM2.5 vs. EMEP measurements

Hourly PM2.5 Aspvreten, SE. 2000

Chemical composition of PM (1):


Spain

0

5

10

15

20

25

Obs Bemantes

Mod Bemantes

Obs Monagrega

Mod Monagrega

Obs Montseny

Mod Montseny

NDotherdustSSOC+ECNH4NO3SO4

Unaccounted PM mass

Vienna Streithofen

PM2.5 Austria,1-6/2000

PM10 PM25

Largest discrepancy:

OC, EC,

dust



Non-C atoms in organic aerosol

Particle-bound water

Measurement artefacts

Full chemical mass closure is rarely achieved .

Unaccounted PM mass - up to 35-40%

Gravimetric method (Reference, EU and EMEP) for determining PM mass requires 48-h conditioning of dust-loaded filters at T=20C and Rh=50% -does not remove all water! At Rh=50% particles can contain 10-30% water

Gravimetrically measured PM mass does not represent

dry PM mass!!!



Spain

0

5

10

15

20

25

Obs Bemantes

M od Bemantes

Obs M onagrega

M od M onagrega

Obs M ontseny

M od M ontseny

ND/waterotherdustSSOC+ECNH4NO3SO4

Unaccounted PM mass in obs

Aerosol water in model

Vienna Streithofen

PM2.5 Austria,1-6/2000 (AUPHEP)

PM10 PM25

To what extend can particle-bound water explain the model underestimation of measured PM?


Modelled dry PM2.5 vs. Identified PM2.5 mass


Accounting for particle-bound water in PM2.5

Model calculations vs. gravimetric PM2.5 (EMEP, 2001)

Dry PM2.5

N=13

Bias=- 47%

Corr=0.69

N=13

Bias=-28%

Corr=0.68

Dry PM2.5 + water


Model calculated dry PM2.5 (blue) and PM2.5 including aerosol water (black) vs. measured PM2.5 (red)

Accounting for water in modelled PM2.5 gives better agreement with measurements…BUT: verification of model calculated aerosol water is needed

An example: Vienna


Daily PM2.5 (June 1999 - June 2000) :

What is needed:

“component-wise” verification of modelled PM

Daily series of SO4, NO3 and NH4 in PM2.5


NO3

NH4

SO4

OC

EC

Na

EC PM emissions validation

Sea salt

Mace Head

Birkenes

Adding a “standard” SOA module to EMEP model gives too much OC and produces summer maxima that are not observed!

(D. Simpson, on-going research)

Organic aerosol in the EMEP model


Meteorological variability

Meteorological variability - Daily summer ozone (JJA)

AVG -1995

AVG -2000

AVG -1996

AVG -1998

AVG -1999

AVG -1997

Annual mean concentrations of PM2.5


2001 2002

Aerosol model

EMEP obs

Annual mean concentrations of PM2.5


1999 2003

Percentage variability of PM2.5due to meteorological conditions


2003-1999 2002-2001

25-35% over European countries 10-20% over European countries

O3 mean Differences due to meteorological conditions


5-10% variations due to meteorology


Scenario Analysis

Reduction in mean concentrations of PM2.5

due to emission changes in 2010


1999 met 2003 met

25-35% changes due to envisaged reduction in emissions (2010)

Similar to meteorological variability ranges from 1999 – 2003

Reduction in mean O3 concentrations due to emission changes in 2010


1999 met 2003 met



Reduction in mean concentrations of PM2.5

due to emission changes in 2020


1999 met 2003 met


Considerably larger than meteorological variability ranges from 1999 – 2003

Reduction in mean O3 concentrations due to emission changes in 2020


1999 met 2003 met




Closing remarks (I)

• Model calculations vs. gravimetric PM2.5 over Europe show an with average 28% underestimation and correlations of 0.68 for n=17 stations – similar to other state-of-art models.

• Conclusions on model performance are at present hampered by the availability of measured PM2.5 chemical components and information on primary PM emissions.

• SOA theories are too immature for application within the EMEP policy framework.

• The EMEP model results should not be used in studies dependent of the analysis of absolute values of PM2.5 but …they are reasonable to study the effect of identified emission changes.


Closing remarks (II)

• Changes in meteorological conditions introduce variability in the scenario analysis that are comparable to the expected variations in PM concentrations due to emission reductions in 2010. In 2020, expected changes due to emission reductions become more significant than the meteorological variations.

• For ozone, envisaged emission reductions both in 2010 and 2020 would impose concentration changes similar to those expected from meteorological variations.

• Calculation of source-receptor calculations for IAM needs to be carried out for as many different meteorological years as plausible : 2003 (on-going), 1999, 2000 …

Title Progress in the development and results of the UNIFIED EMEP model Presented by Leonor Tarrason...

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