modelling soa in emep: experiments with the vbs approach robert bergström(1,2) and david...

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 -pinene +O3

Kamens et al., 1999

First EMEP-SOA – Andersson-Sköld & Simpson 2001

Based on Kamens et al., 1999Added 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

0.01

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1

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100

1000

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0.01 0.1 1 10 100 1000 10000

Measured SOA production (ug/m3)

Mo

de

l SO

A p

rod

uc

tio

n (

ug

/m3

)

0.01

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0.01 0.1 1 10 100 1000 10000

Measured SOA production (ug/m3)

Mo

de

l SO

A p

rod

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tio

n (

ug

/m3

)

K model by Svendby et al., 2008

0.01

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Measured SOA production (ug/m3)

Mo

de

l SO

A p

rod

uc

tio

n (

ug

/m3

)

VBS model by Pathak et al., 2007

Evaluation of gas/particle SOA mechanisms for -pinene for the EMEP modelRobert 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

References – models

Andersson-Sköld, Y. & Simpson, D. (2001), Secondary organic aerosol formation in Northern Europe: A model study, J. Geophys. Res., 106, 7357-7374.

Kamens, R.; Jang, M.; Chien, C. & Leach, K. (1999), Aerosol Formation from the Reaction of -Pinene and Ozone Using a Gas-Phase Kinetics-Aerosol Partitioning Model, Environ. Sci. Technol., 33, 1430-1438.

Kamens, R.M. & Jaoui, M. (2001), Modeling Aerosol Formation from -Pinene + NOx in the Presence of Natural Sunlight Using Gas-Phase Kinetics and Gas-Particle Partitioning Theory, Environ. Sci. Technol., 35, 1394-1405.

Li, Q.; Hu, D.; Leungsakul, S. & Kamens, R.M. (2007), Large outdoor chamber experiments and computer simulations: (I) Secondary organic aerosol formation from the oxidation of a mixture of d-limonene and -pinene, Atmos. Environ., 41, 9341-9352.

Pathak, R.K.; Presto, A.A.; Lane, T.E.; Stanier, C.O.; Donahue, N.M. & Pandis, S.N. (2007), Ozonolysis of -pinene: parameterization of secondary organic aerosol mass fraction, Atmos. Chem. Phys., 7, 3811-3821.

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.

Svendby, T.M.; Lazaridis, M. & Tørseth, K. (2008), Temperature dependent secondary organic aerosol formation from terpenes and aromatics, J. Atmos.

Chem., 59, 25-46.

measurementsCocker 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: -pinene/ozone system , Atmos. Environ., 35, 6049-6072.

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.

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.

Jang, M. & Kamens, R.M. (1999), Newly characterized products and composition of secondary aerosols from the reaction of -pinene with ozone, Atmos. Environ., 33, 459-474.

Pathak, R.K.; Stanier, C.O. Donahue, N.M. & Pandis, S.N. (2007), Ozonolysis of -pinene at atmospherically relevant concentrations: Temperature dependence of aerosol mass fractions (yields), J. Geophys. Res., 112, D03201.

Presto, A.A.; & Donahue, N. M. (2006), Investigation of -pinene + Ozone Secondary Organic Aerosol Formation at Low Total Aerosol Mass, Environ. Sci. Technol., 40, 3536-3543.

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 -pinene and limonene, Atmos. Chem. Phys., 9, 1551-1577.

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 -pinene, Atmos. Chem. Phys., 8, 2073-2088.

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.

Acknowledgement 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 Interactions (EUCAARI).

SummaryThe EMEP MSC-W model for secondary organic aerosol (SOA) has so far made use of a semi-explicit gas/particle partitioning scheme for -pinene, in which -pinene chemistry is represented by 30 reactions between 17 species. The mechanism, described in Andersson-Sköld and Simpson (2001), was based upon a dark-chemistry scheme for -pinene presented by Kamens et al. (1999). The original EMEP SOA model was tested against 11 smog-chamber experiments in 2001, and found to reproduce observed SOA quite well across a wide-range of temperature and -pinene levels.

In recent years a number of new studies have become available which necessitate revisions and new testing of the EMEP SOA scheme. As shown in Simpson et al. (2007), assumptions concerning the vapour pressure of specific compounds can have pronounced effects on predicted SOA amounts. The Kamens group has also presented new ideas for the -pinene mechanism (e.g., Li et al., 2007).

The EMEP SOA scheme is being re-written in the light of these new developments, and here we present some preliminary results for revised SOA schemes compared to recent smog-chamber data and to some modern parameterised -pinene SOA models (Two-product, -K, model by Svendby et al., 2008 and Volatility Basis Set models by Pathak et al., 2007)

• High NOx experiments are poorly modelled (by the EMEP/Kamens schemes)

• Many of the Kamens-based schemes have a tendency to underestimate SOA at high temperatures and at low (measured) OA levels

• The box model version of the Kam2X scheme overestimates SOA substantially for most experiments

•The 2-product model of Svendby et al. (2008) and the VBS model by Pathak et al. (2007) are both giving SOA concentrations in better agreement with measurements in most cases

NO3 reaction

Sensitivity to NOx/VOC ratio

SOA from ozonolysis - Model / Measurement - K / VBS schemes

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100

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8NOx/VOC_C ratio (ppb NOx / ppb C)

Mo

del

SO

A /

Mea

sure

d S

OA

Svendby08 Pathak07dry

0.001

0.01

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0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8NOx/VOC_C ratio (ppb NOx / ppb C)

Mo

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sure

d S

OA

K01 K07 AS01e S07a S07b S07x

EMEP / Kamens type schemes

K & VBS models

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0 50 100 150 200 250 300 350 400 450 500Low NOx Experiments with OH scavenger (2-butanol) - SOA Mass (measured)

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d S

OA

K01 K07 AS01e S07a S07b S07x

SOA from ozonolysis - Model / Measurement - K / VBS schemes

0

0.5

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1.5

2

2.5

0 50 100 150 200 250 300 350 400 450 500Low NOx Experiments with OH scavenger (2-butanol) - SOA Mass (measured)

Mo

del

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Mea

sure

d S

OA

Svendby08 Pathak07dry

Results – dark ozonolysis studies

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Measured SOA production (ug/m3)

Mo

del

SO

A p

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ion

(u

g/m

3)

K07 – Li et al., 2007 scheme

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Measured SOA production (ug/m3)

Mo

del

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A p

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ion

(u

g/m

3)

AS01e – Andersson-Sköld & Simpson, 2001

0.01

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Measured SOA production (ug/m3)

Mo

del

SO

A p

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ion

(u

g/m

3)

S07a –box-v of Kam2 fr Simpson et al., 2007

0.01

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Measured SOA production (ug/m3)

Mo

del

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A p

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uct

ion

(u

g/m

3)

S07x –box-v of Kam2X fr Simpson et al., 2007

0.01

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0.01 0.1 1 10 100 1000 10000

Measured SOA production (ug/m3)

Mo

del

SO

A p

rod

uct

ion

(u

g/m

3)

Svendby08 – K model by Svendby et al., 2008

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Measured SOA production (ug/m3)

Mo

del

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A p

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uct

ion

(u

g/m

3)

Pathak07dry – VBS model by Pathak et al., 2007

SOA from ozonolysis - Model / Measurement - Kamens/EMEP schemes

0.001

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240 250 260 270 280 290 300 310 320 330Temperature (K)

Mo

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sure

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K01 K07 AS01e S07a S07b S07x

Sensitivity to Temperature

SOA from ozonolysis - Model / Measurement - K / VBS schemes

0.1

1

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240 250 260 270 280 290 300 310 320 330Temperature (K)

Mo

de

l S

OA

/ M

ea

su

red

SO

A

Svendby08 Pathak07dry

Low-NOx studies

SOA from -pinene + NO3 reaction (experiment by Hallquist et al., 1999)

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

0.00% 5.00% 10.00% 15.00% 20.00% 25.00% 30.00%

Experimental yield (mass fraction, assuming density in the interval 1.0-1.7 g cm -3)

Mo

del

SO

A y

ield

Svendby08K01K07AS01eS07aS07bS07x

The Volatility Basis Set (VBS) approach to (S)OA modelling

VBS: Gas – Particle partitioningDefine a partitioning coefficient i, 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 i values are free parameters when fitting experimental data, e.g.,

{Ci*} = {0.01, 0.1, 1, 10, 100, 1000, 10 000, 100 000} g m-3

{Ci*} = {1, 10, 100, 1000} g 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 – VBSVBS-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-SOAIncluding VBS-SOA schemes for

•Monoterpenes (BSOA)

•Isoprene (BSOA)

•Alkanes (ASOA)

•Alkenes (ASOA)

•Aromatics (ASOA)

EMEP – VBS - POADifferent 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 - agingDifferent 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 resultsFour different model versions have been run for the years 2002-2003, 2006, 2007

•Validation just started

Inert POA emissions

Age POA

VBS-POA(no aging)

Age POA + SOA

OC – yearly average conc 2003 (g C / m3)

Inert POA emissions

VBSPOA-aging

Fresh POA

VBS-POA(no aging)

VBSPOA-aging

Oxidised POA

POA & OPOA (from FFUEL)–2007 (g C / m3)

Inert POA emissions

Age POA

VBS-POA(no aging)

Age POA + SOA

ASOA – yearly average conc 2003 (g C / m3)

Inert POA emissions

Age POA

VBS-POA(no aging)

Age POA + SOA

BSOA – yearly average conc 2003 (g C / m3)

(Age POA)Isoprene-BSOA

(Age POA+SOA)Isoprene-BSOA

(Age-POA)Terpene-BSOA

(Age POA + SOA)Terpene-BSOA

BSOA – yearly average conc 2003 (g C / m3)

Source-apportionment K-Puszta (Hungary), Summer 2002-2003 Obs.-

Derived(1)

EMEP-VBS Models

Sources (5–95th %ile)

Inert POA

VBS-POA(2)

Age POA(2)

Age 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: g C m-3

Source-apportionment Hurdal (Norway), Summer 2006 (SORGA) Obs.-

Derived(1)

EMEP-VBS Models

Sources (5–95th %ile)

Inert POA

VBS-POA(2)

Age POA(2)

Age 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: g C m-3

Source-apportionment Gothenburg (Sweden), Summer (Göte-2006) Obs.-

Derived(1)

EMEP-VBS Models

Sources (5–95th %ile)

Inert POA

VBS-POA(2)

Age POA(2)

Age 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: g 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?

2D-VBS: Keep track of O:C ratios as well as volatility

VBS-2d discussion

VBS: Gas – particle partitioning

VBS details US studies – emissions ageing etc

VBS-2d discussion

[Taken from Neil Donahue]