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									Modelling SOA in EMEP:
Experiments with the VBS Approach
Robert Bergström(1,2) and David Simpson(3,4)
Robert.Bergstrom@smhi.se, David.Simpson@met.no
(1) Department of Chemistry, University of Gothenburg, Sweden
(2) Swedish Meteorological and Hydrological Institute, SE-601 76 Norrköping, Sweden
(3) The Norwegian Meteorological Institute, Oslo, Norway
(4) Dept of Radio and Space Science, Chalmers University of Technology, Gothenburg, Sweden
Outline

•Earlier EMEP SOA models
•Evaluation (using smog chamber data)
•EMEP VBS-model
•Preliminary results
History of EMEP-SOA – Kamens et al., 1999
   Kamens et al., 1999 aerosol from a-pinene +O3




Kamens et al., 1999
First EMEP-SOA – Andersson-Sköld & Simpson 2001




Based on Kamens et al., 1999
Added NOx-chemistry, photolysis, dimer formation (from
gas phase reaction of pinic and norpinic acid)
Implementation in 3d-model (EMEP)
First EMEP-SOA “Kam-2” – Andersson-Sköld & Simpson
2001
 Added ca 17 species and 30 reactions to the standard
 EMEP photochemistry scheme
Simpson et al., JGR 2007 (Kam2-X)
Kamens & Jaoui, 2001
Li et al., 2007 “Kamens 2007”




    Updating the Kamens 2001 scheme,
    exploratory “oligomerization” reactions
    introduced
A new EMEP-SOA model
needed(?)
Testing:
Kamens 2001
Kamens 2007
Volatility Basis Set - based methods (Donahue
et al., Lane et al.)
       Example of Evaluation (dark ozonolysis, SOA yield)

        Kamens2007                                                                                         aK model by Svendby et al., 2008

                Measured SOA production (ug/m3)
0.01      0.1    1            10           100    1000     10000                                                                        Measured SOA production (ug/m3)
                                                               10000                                       0.01          0.1             1              10            100                                  1000   10000
                                                                                                                                                                                                                      10000

                                                              1000




                                                                       Model SOA production (ug/m3)
                                                                                                                                                                                                                     1000




                                                                                                                                                                                                                              Model SOA production (ug/m3)
                                                              100
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                                                              10
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                                                              1
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                                                              0.1
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                                                              0.01
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                                                                                                      Measured SOA production (ug/m3)
                                                    0.01      0.1                                      1            10           100             1000         10000
                                                                                                                                                                  10000


       VBS model by Pathak et                                                                                                                                     1000




                                                                                                                                                                            Model SOA production (ug/m3)
       al., 2007                                                                                                                                                  100



                                                                                                                                                                  10



                                                                                                                                                                  1



                                                                                                                                                                  0.1



                                                                                                                                                                  0.01
                              Evaluation of gas/particle SOA mechanisms for a-pinene for the EMEP model
                              Robert Bergström (1,2) and David Simpson (3,4)
                              (1) Department of Chemistry, University of Gothenburg, Sweden, (2) Swedish Meteorological and Hydrological Institute, SE-601 76 Norrköping, Sweden Robert.Bergstrom@smhi.se
                              (3) The Norwegian Meteorological Institute, Oslo, Norway, (4) Dept of Radio and Space Science, Chalmers University of Technology, Gothenburg, Sweden David.Simpson@met.no

                                                    Summary                                                                                               Results – dark ozonolysis studies                                                                                                                                                             Sensitivity to NOx/VOC ratio                                                                                                                 Sensitivity to Temperature                                                                                                                      Low-NOx studies
                                                                                                                                            K07 – Li et al., 2007 scheme                                                                        AS01e – Andersson-Sköld & Simpson, 2001                                                                                                                                                                                                              EMEP / Kamens type schemes
                  The EMEP MSC-W model for secondary organic                                                                                               Measured SOA production (ug/m3)                                                                     Measured SOA production (ug/m3)
                                                                                                                                                                                                                                                                                                                                                    SOA from ozonolysis - Model / Measurement - Kamens/EMEP schemes
                                                                                                                                                                                                                                                                                                                                                                           NOx/VOC_C ratio (ppb NOx / ppb C)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               SOA from ozonolysis - Model / Measurement - Kamens/EMEP schemes
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Temperature (K)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         SOA from ozonolysis - Model / Measurement - Kamens/EMEP schemes
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              Low NOx Experiments with OH scavenger (2-butanol) - SOA Mass (measured)
                                                                                                                                          0.01    0.1       1            10           100    1000   10000                                        0.01   0.1     1            10           100    1000   10000                                       0      0.2     0.4     0.6     0.8        1       1.2        1.4   1.6   1.8                                                               240    250      260     270     280     290          300      310   320   330                                                             0     50     100    150      200     250     300     350      400    450     500
                  aerosol (SOA) has so far made use of a semi-explicit                                                                                                                                  10000                                                                                               10000                                                                                                                  1000                                                                                                                                     1000                                                                                                                                         10


                  gas/particle partitioning scheme for a-pinene, in                                                                                                                                     1000                                                                                               1000                                                                                                                    100                                                                                                                                      100

                  which a-pinene chemistry is represented by 30




                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Model SOA / Measured SOA
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              Model SOA / Measured SOA
                                                                                                                                                                                                                                                                                                                                                                                                                                                                    Model SOA / Measured SOA
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                1




                                                                                                                                                                                                                 Model SOA production (ug/m3)




                                                                                                                                                                                                                                                                                                                    Model SOA production (ug/m3)
                                                                                                                                                                                                                                                                                                                                                                                                                                   10                                                                                                                                       10
                                                                                                                                                                                                        100                                                                                                100
                  reactions between 17 species. The mechanism,
                                                                                                                                                                                                                                                                                                                                                                                                                                   1                                                                                                                                        1                                                                                                                                                   0.1
                  described in Andersson-Sköld and Simpson (2001),                                                                                                                                      10                                                                                                 10


                  was based upon a dark-chemistry scheme for a-                                                                                                                                         1                                                                                                  1
                                                                                                                                                                                                                                                                                                                                                                                                                                   0.1                                                                                                                                      0.1
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                0.01

                  pinene presented by Kamens et al. (1999). The                                                                                                                                                                                                                                                                                                                                                                    0.01                                                                                                                                     0.01
                                                                                                                                                                                                        0.1                                                                                                0.1
                  original EMEP SOA model was tested against 11                                                                                                                                                                                                                                                                                                                                                                    0.001                                                                                                                                    0.001                                                                                                                                               0.001

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                K01   K07    AS01e     S07a    S07b       S07x                                                                                             K01    K07    AS01e     S07a     S07b    S07x
                  smog-chamber experiments in 2001, and found to                                                                                                                                        0.01                                                                                               0.01                                                     K01    K07     AS01e     S07a    S07b    S07x


                  reproduce observed SOA quite well across a wide-                                                                                                                                                                                                                                                                                                                                                                                                                                               aK & VBS models
                                                                                                                                         S07a –box-v of Kam2 fr Simpson et al., 2007                                                            S07x –box-v of Kam2X fr Simpson et al., 2007
                  range of temperature and a-pinene levels.
                                                                                                                                                                                                                                                                                                                                                    SOA from ozonolysis - Model / Measurement - aK / VBS schemes                                                                                SOA from ozonolysis - Model / Measurement - aK / VBS schemes                                                                             SOA from ozonolysis - Model / Measurement - aK / VBS schemes
                                                                                                                                                                                                                                                                                                                                                                                 NOx/VOC_C ratio (ppb NOx / ppb C)                                                                                                                   Temperature (K)                                                                                                 Low NOx Experiments with OH scavenger (2-butanol) - SOA Mass (measured)
                                                                                                                                                                                                                                                                                                                                                    0     0.2      0.4     0.6        0.8       1       1.2      1.4   1.6   1.8                                                               240    250      260     270     280       290       300       310   320   330                                                             0      50      100    150      200      250     300      350       400     450      500
                                                                                                                                                           Measured SOA production (ug/m3)                                                                     Measured SOA production (ug/m3)
                                                                                                                                                                                                                                                                                                                                                                                                                                   100                                                                                                                                      100                                                                                                                                                 2.5
                                                                                                                                          0.01    0.1       1            10           100    1000   10000                                        0.01   0.1     1            10           100    1000   10000
                  In recent years a number of new studies have                                                                                                                                          10000                                                                                               10000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                2
                  become available which necessitate revisions and




                                                                                                                                                                                                                                                                                                                                                                                                                                         Model SOA / Measured SOA




                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   Model SOA / Measured SOA




                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      Model SOA / Measured SOA
                                                                                                                                                                                                        1000                                                                                               1000
                                                                                                                                                                                                                                                                                                                                                                                                                                   10                                                                                                                                      10
                  new testing of the EMEP SOA scheme. As shown in




                                                                                                                                                                                                                 Model SOA production (ug/m3)




                                                                                                                                                                                                                                                                                                                    Model SOA production (ug/m3)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                1.5

                                                                                                                                                                                                        100                                                                                                100
                  Simpson et al. (2007), assumptions concerning the                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             1

                  vapour pressure of specific compounds can have                                                                                                                                        10                                                                                                 10                                                                                                                      1                                                                                                                                       1

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                0.5
                  pronounced effects on predicted SOA amounts. The                                                                                                                                      1                                                                                                  1

                  Kamens group has also presented new ideas for the                                                                                                                                                                                                                                                                                                                                                                0.1                                                                                                                                     0.1
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     Svendby08     Pathak07dry
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                0



                  a-pinene mechanism (e.g., Li et al., 2007).
                                                                                                                                                                                                        0.1                                                                                                0.1                                                              Svendby08      Pathak07dry                                                                                                                  Svendby08     Pathak07dry


                                                                                                                                                                                                        0.01                                                                                               0.01

                  The EMEP SOA scheme is being re-written in the
                  light of these new developments, and here we                                                                     Svendby08 – aK model by Svendby et al., 2008                                                                   Pathak07dry – VBS model by Pathak et al., 2007
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     References – models
                  present some preliminary results for revised SOA                                                                                         Measured SOA production (ug/m3)                                                                     Measured SOA production (ug/m3)                                                                            Andersson-Sköld, Y. & Simpson, D. (2001), Secondary organic aerosol formation in Northern Europe: A model study, J. Geophys. Res., 106, 7357-7374.
                                                                                                                                          0.01    0.1       1            10           100    1000   10000                                        0.01   0.1     1            10           100    1000   10000

                  schemes compared to recent smog-chamber data                                                                                                                                          10000                                                                                               10000                                                         Kamens, R.; Jang, M.; Chien, C. & Leach, K. (1999), Aerosol Formation from the Reaction of a-Pinene and Ozone Using a Gas-Phase Kinetics-Aerosol
                                                                                                                                                                                                                                                                                                                                                                          Partitioning Model, Environ. Sci. Technol., 33, 1430-1438.
                  and to some modern parameterised a-pinene SOA                                                                                                                                        1000                                                                                                 1000
                                                                                                                                                                                                                                                                                                                                                                          Kamens, R.M. & Jaoui, M. (2001), Modeling Aerosol Formation from a-Pinene + NOx in the Presence of Natural Sunlight Using Gas-Phase Kinetics and
                  models (Two-product, a-K, model by Svendby et al.,
                                                                                                                                                                                                                Model SOA production (ug/m3)




                                                                                                                                                                                                                                                                                                                     Model SOA production (ug/m3)
                                                                                                                                                                                                       100                                                                                                  100
                                                                                                                                                                                                                                                                                                                                                                          Gas-Particle Partitioning Theory, Environ. Sci. Technol., 35, 1394-1405.
                  2008 and Volatility Basis Set models by Pathak et                                                                                                                                                                                                                                                                                                       Li, Q.; Hu, D.; Leungsakul, S. & Kamens, R.M. (2007), Large outdoor chamber experiments and computer simulations: (I) Secondary organic aerosol
                  al., 2007)                                                                                                                                                                           10                                                                                                   10                                                            formation from the oxidation of a mixture of d-limonene and a-pinene, Atmos. Environ., 41, 9341-9352.

                                                                                                                                                                                                       1                                                                                                    1
                                                                                                                                                                                                                                                                                                                                                                          Pathak, R.K.; Presto, A.A.; Lane, T.E.; Stanier, C.O.; Donahue, N.M. & Pandis, S.N. (2007), Ozonolysis of a-pinene: parameterization of secondary
                                                                                                                                                                                                                                                                                                                                                                          organic aerosol mass fraction, Atmos. Chem. Phys., 7, 3811-3821.
                                                                                                                                                                                                       0.1                                                                                                  0.1
                                                                                                                                                                                                                                                                                                                                                                          Simpson, D.; Yttri, K. E.; Klimont, Z.; Kupiainen, K.; Caseiro, A.; Gelencsér, A.; Pio, C. & Legrand, M. (2007), Modeling carbonaceous aerosol over
                                                                                                                                                                                                                                                                                                                                                                          Europe: Analysis of the CARBOSOL and EMEP EC/OC campaigns, J. Geophys. Res., 112, D23S14.
                                                                                                                                                                                                       0.01                                                                                                 0.01
                                                                                                                                                                                                                                                                                                                                                                          Svendby, T.M.; Lazaridis, M. & Tørseth, K. (2008), Temperature dependent secondary organic aerosol formation from terpenes and aromatics, J. Atmos.
                                                                                                                                                                                                                                                                                                                                                                          Chem., 59, 25-46.
                                                   NO3 reaction                                                                                         • High NOx experiments are poorly modelled (by the                                                                                                                                                                                                                                                                                                                       measurements
                           SOA from a-pinene + NO3 reaction (experiment by Hallquist et al., 1999)                                                                                                                                                                                                                                                                        Cocker III, D.R.; Clegg, S.L.; Flagan, R.C. & Seinfeld, J.H. (2001), The effect of water on gas-particle partitioning of secondary organic aerosol. Part I: a-pinene/ozone system , Atmos. Environ., 35, 6049-
                  70.00%                                                                                                                                EMEP/Kamens schemes)                                                                                                                                                                                              6072.
                                                                                                                                                                                                                                                                                                                                                                          Griffin, R.J.; Cocker III, D.R.; Flagan, R.C. & Seinfeld, J.H. (1999), Organic aerosol formation from the oxidation of biogenic hydrocarbons, J. Geophys. Res., 104, 3555-3567.


                                                                                                                                                        • Many of the Kamens-based schemes have a tendency to
                  60.00%                                                                                                                                                                                                                                                                                                                                                  Hallquist, M.; Wängberg, I.; Ljungström, E.; Barnes, I. & Becker, K.-H. (1999), Aerosol and Product Yields from NO3 Radical-Initiated Oxidation of Selected Monoterpenes, Environ. Sci. Technol., 33, 553-559.
                                                                                                                                                                                                                                                                                                                                                                          Hoffmann, T.; Odum, J.R.; Bowman, F.; Collins, D.; Klockow, D.; Flagan, R.C. & Seinfeld, J.H. (1997), Formation of Organic Aerosols from the Oxidation of Biogenic Hydrocarbons, J. Atmos. Chem., 26, 189-
                                                                                                                                                                                                                                                                                                                                                                          222.
                  50.00%
                                                                                                                             Svendby08
                                                                                                                             K01
                                                                                                                                                        underestimate SOA at high temperatures and at low                                                                                                                                                                 Jang, M. & Kamens, R.M. (1999), Newly characterized products and composition of secondary aerosols from the reaction of a-pinene with ozone, Atmos. Environ., 33, 459-474.
Model SOA yield




                                                                                                                             K07                                                                                                                                                                                                                                          Pathak, R.K.; Stanier, C.O. Donahue, N.M. & Pandis, S.N. (2007), Ozonolysis of a-pinene at atmospherically relevant concentrations: Temperature dependence of aerosol mass fractions (yields), J. Geophys.
                  40.00%                                                                                                     AS01e
                                                                                                                             S07a                       (measured) OA levels                                                                                                                                                                                              Res., 112, D03201.
                                                                                                                             S07b                                                                                                                                                                                                                                         Presto, A.A.; & Donahue, N. M. (2006), Investigation of a-pinene + Ozone Secondary Organic Aerosol Formation at Low Total Aerosol Mass, Environ. Sci. Technol., 40, 3536-3543.
                                                                                                                             S07x


                                                                                                                                                        • The box model version of the Kam2X scheme
                  30.00%                                                                                                                                                                                                                                                                                                                                                  Presto, A.A.; Huff Hartz, K.E. & Donahue, N. M. (2005), Secondary Organic Aerosol Production from Terpene Ozonolysis. 2. Effect of NOx Concentration, Environ. Sci. Technol., 39, 7046-7054.
                                                                                                                                                                                                                                                                                                                                                                          Saathoff, H.; Naumann, K.-H.; Möhler, O.; Jonsson, Å.M.; Hallquist, M.; Kiendler-Scharr, A.; Mentel, Th.F.; Tillmann, R. & Schurath, U. (2009), Temperature dependence of yields of secondary organic
                                                                                                                                                                                                                                                                                                                                                                          aerosols from the ozonolysis of a-pinene and limonene, Atmos. Chem. Phys., 9, 1551-1577.
                  20.00%
                                                                                                                                                        overestimates SOA substantially for most experiments                                                                                                                                                              Shilling, J.E.; Chen, Q.; King, S.M.; Rosenoern, T.; Kroll, J.H.; Worsnop, D.R.; McKinney, K.A. & Martin, S.T. (2008), Particle mass yield in secondary organic aerosol formed by the dark ozonolysis of a-
                                                                                                                                                                                                                                                                                                                                                                          pinene, Atmos. Chem. Phys., 8, 2073-2088.
                  10.00%

                                                                                                                                                        •The 2-product model of Svendby et al. (2008) and the                                                                                                                                                             Yu, J.; Cocker III, D.R.; Griffin, R.J.; Flagan, R.C. & Seinfeld, J.H. (1999), Gas-Phase Ozone Oxidation of Monoterpenes: Gaseous and Particulate Products, J. Atmos. Chem., 34, 207-258.

                  0.00%
                      0.00%         5.00%          10.00%          15.00%          20.00%         25.00%            30.00%                              VBS model by Pathak et al. (2007) are both giving SOA                                                                                                                                                                                                                                                                                                   Acknowledgement
                              Experimental yield (mass fraction, assuming density in the interval 1.0-1.7 g cm-3)
                                                                                                                                                        concentrations in better agreement with measurements in                                                                                                                                                           This work was funded by the Swedish Environmental Protection Agency, as part of the Swedish Clean Air Research
                                                                                                                                                                                                                                                                                                                                                                          Programme (SCARP) and by EU, as part of the European Integrated project on Aerosol Cloud Climate and Air Quality
                                                                                                                                                        most cases                                                                                                                                                                                                        Interactions (EUCAARI).
The Volatility Basis Set (VBS)
approach to (S)OA modelling
 VBS: Gas – Particle partitioning
Define a partitioning coefficient xi, for compound i




where
Ci* = effective saturation concentration
COA= mass concentration of OA
                                VBS: The basis set
Use a fixed set of effective saturation concentrations, i.e.,
only ai values are free parameters when fitting experimental
data, e.g.,
{Ci*} = {0.01, 0.1, 1, 10, 100, 1000, 10 000, 100 000} mg m-3
{Ci*} = {1, 10, 100, 1000} mg m-3
[From Neil Donahue]
Temperature dependence

Clausius-Clapeyron equation for saturation
concentration
Reactive / Aging POA emissions

Shrivastava et al. (2008) use a VBS-approach for treating
primary organic aerosol (POA) emissions
Assume a lot of the POA emissions are of intermediate
volatility and that chemical processing of these gas phase
components lead to a lowering of the volatility and
increased partitioning into the particle phase
Total POA/IVOC emissions are assumed to be 2.5 times
larger than the “traditional” estimates for “inert” POA but
most of the direct emissions are in the gaseous phase
  Aging POA
  emissions
Shrivastava et al., 2008
EMEP – VBS
VBS-chemistry based on Lane et al.,
2008
EMEP – VBS-SOA
•Standard EMEP photochemistry model with
added VBS treatment of SOA (and POA)
•EUCAARI/TNO emissions for EC/OC used
(Denier van der Gon et al., 2009)
•Vegetation fire emissions from Global Fire
Emission Database (GFEDv2), 8day time
resolution (2001-2007) (van der Werf et al., 2006, Giglio
et al., 2003)
http://ess1.ess.uci.edu/%7Ejranders/data/GFED2/
EMEP – VBS-SOA
Including VBS-SOA schemes for
•Monoterpenes (BSOA)
•Isoprene (BSOA)
•Alkanes (ASOA)
•Alkenes (ASOA)
•Aromatics (ASOA)
EMEP – VBS - POA
Different assumptions regarding the POA
emissions are tested:
•Traditional inert (nonvolatile) POA emissions
•Emissions distributed into nine volatility bins
and using the same assumptions as
Shrivastava et al. (2008) regarding “missing”
IVOC emissions in the POA inventories
EMEP – VBS - aging
Different assumptions regarding the aging
reactions (by OH) are tested:
•No aging
•Only aging of the primary emissions
•Aging of both POA (k=4×10-11 cm3 molecule-1 s-1)
and SOA (k=4×10-12 cm3 molecule-1 s-1)
    –   see Lane et al., Atmos. Environ. 42 (2008) p7439-7451 for a test of
        SOA aging reactions using the PMCAMx VBS model
EMEP – VBS preliminary results
Four different model versions have been run for
the years 2002-2003, 2006, 2007
•Validation just started
             OC – yearly average conc 2003 (mg C / m3)

Inert POA
                                             VBS-POA
 emissions
                                             (no aging)




Age POA                                      Age POA +
                                             SOA
             POA & OPOA (from FFUEL)–2007 (mg C / m3)

Inert POA                                     VBS-POA
 emissions                                    (no aging)




VBS                                          VBS
POA-                                         POA-
aging                                        aging
Fresh                                        Oxidised
POA                                          POA
             ASOA – yearly average conc 2003 (mg C / m3)

Inert POA
                                               VBS-POA
 emissions
                                               (no aging)




Age POA                                        Age POA +
                                               SOA
             BSOA – yearly average conc 2003 (mg C / m3)

Inert POA
                                               VBS-POA
 emissions
                                               (no aging)




Age POA                                        Age POA +
                                               SOA
            BSOA – yearly average conc 2003 (mg C / m3)

(Age POA)
                                              (Age-POA)
Isoprene-
                                              Terpene-
BSOA
                                              BSOA




(Age POA+                                     (Age POA +
SOA)                                          SOA)
Isoprene-                                     Terpene-
BSOA                                          BSOA
Source-apportionment
K-Puszta (Hungary), Summer 2002-2003
             Obs.-                   EMEP-VBS Models
             Derived(1)
Sources      (5–95th        Inert   VBS-      Age        Age
                                         (2)      (2)
             %ile)          POA     POA      POA      POA(2)+SOA
OCff          0.15 – 0.49   0.33     0.17     0.48       0.49
OCbb          0.27 – 0.52   0.13     0.13     0.13       0.13
OCbio         0.13 – 0.46     -        -        -          -
ASOA          0.05 – 0.77   0.27     0.25     0.28       1.02
SOAnf         2.85 – 3.58   0.44     0.41     0.45       2.18
BGNDOC                       0.5     0.5       0.5        0.5
(1) From Gelencsér et al., JGR 2007, vol 112 D23S04 CARBOSOL project
(2) Primary emissions distributed as in Shrivastava et al., JGR 2008

Units: mg C m-3
Source-apportionment
Hurdal (Norway), Summer 2006 (SORGA)
              Obs.-                      EMEP-VBS Models
              Derived(1)
Sources       (5–95th          Inert     VBS-      Age        Age
                                              (2)      (2)
              %ile)            POA       POA      POA      POA(2)+SOA
OCff           0.10 – 0.15     0.14      0.065     0.19       0.20
ASOA          0.017 – 0.20     0.14       0.13     0.14       0.42
OCnf           0.99 – 1.14     1.07       1.05     1.08       2.57
PBAP          0.017 – 0.05       -          -        -          -
BGNDOC                          0.5       0.5       0.5        0.5
(1) Yttri et al., EGU 2009
(2) Primary emissions distributed as in Shrivastava et al., JGR 2008

Units: mg C m-3
Source-apportionment
Gothenburg (Sweden), Summer (Göte-2006)
              Obs.-                      EMEP-VBS Models
              Derived(1)
Sources       (5–95th          Inert     VBS-     Age        Age
                                             (2)      (2)
              %ile)            POA       POA     POA      POA(2)+SOA
OCfossil       0.65 – 1.0      0.42       0.22    0.46       0.88
OCff           0.19 – 0.30     0.28       0.09    0.32       0.33
ASOA           0.38 – 0.78     0.14       0.13    0.14       0.56
OCnf           0.95 – 1.35     0.49       0.47    0.49       2.14
BGNDOC                          0.5       0.5      0.5        0.5
(1) Szidat et al., Atmos. Chem. Phys., 9, 1521-1535, 2009
(2) Primary emissions distributed as in Shrivastava et al., JGR 2008

Units: mg C m-3
Preliminary results
On-going work…

Evaluation against EUCAARI measurements
(AMS, etc) – to be presented at IAC Helsinki
(August 2010)
Acknowledgements

Thanks to:
•Swedish Clean Air Research Programme
(SCARP)
•EMEP project
•EU EUCAARI project
•Norwegian SORGA project
Next generation VBS-2D?
    VBS-2d discussion




2D-VBS: Keep track of O:C ratios
as well as volatility
[Taken from Neil Donahue]


      VBS: Gas – particle partitioning

      VBS details US studies – emissions ageing etc
      VBS-2d discussion

								
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