Parameterization of SOA formation for α- pinene , based on a detailed mechanism

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Parameterization of SOA formation for α-pinene, based on a detailed mechanism Karl Ceulemans– Steven Compernolle – Jean-François Müller Belgian Institute for Space Aeronomy, Brussels, Belgium Eurochamp 2 Workshop, Manchester, 2011

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Parameterization of SOA formation for α- pinene , based on a detailed mechanism. Karl Ceulemans – Steven Compernolle – Jean-François Müller Belgian Institute for Space Aeronomy , Brussels, Belgium. Eurochamp 2 Workshop, Manchester, 2011. Outline. - PowerPoint PPT Presentation

Transcript of Parameterization of SOA formation for α- pinene , based on a detailed mechanism

Page 1: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Parameterization of SOA formation for α-pinene, based on a detailed mechanism

Karl Ceulemans– Steven Compernolle – Jean-François Müller Belgian Institute for Space Aeronomy, Brussels, Belgium

Eurochamp 2 Workshop, Manchester, 2011

Page 2: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Outline

BOREAM: Detailed model for α-pinene SOA

Simulations of smog chamber experiments

10-product model parameterization including ageing

Page 3: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

BOREAM : explicit model for α-pinene SOA

Gas phase reaction model with additional generic chemistry and aerosol formation module

10000 reactions, 2500 compoundsUsing KPP solverCapouet et al. (2008), Ceulemans et al. (2010)

Page 4: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Explicit chemistry• Based on

advanced theoretical calculations and SARs

• Oxidation by OH, O3 and NO3

• Oxidation products react with OH or photolyse (now also in aerosol phase)

• Vapour pressure method: Capouet & Müller (2006)

Page 5: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Generic chemistrySecond generation oxidation products lumped

into semi-generic and generic products

• Semi-generic: carbon number and functional groups

• Generic: carbon number, vapour pressure classes (11) and 1explicit functional group

LA10HPP

10 carbons1 alcohol &2 hydroperoxide

Implicit parent structure, with pvap,im

LX9cONO2

Page 6: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Smog chamber Photo-oxidationlow-NOx experiments (Ng et al. 2007) α-pinene and O3 given in Valorso et al. (2011) Initial: 330 ppt NO, 330 ppt NO2 , 4 ppb O3 ,

blacklights

α-pinene decay well-reproducedozone : reasonable agreement, sensitive to

assumptions!

Page 7: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Smog chamber Photo-oxidation: SOA evolution

for Ng et al. 2007 exp. 1 (low NOx):

SOA mass yields are overestimated: experimental SOA yield is 40%, BOREAM simulation: 60%

Page 8: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Smog chamber Photo-oxidation: SOA composition

Molar composition for Ng et al. (2007) exp. 1 (low NOx):

SOA is dominated by hydroxy dihydroperoxidesParticle phase chemistry of hydroperoxides?

Page 9: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Model performance: Photo-oxidation

two low-NOx experiments, (Ng et al. 2007) ; somewhat overestimated

most SOA yields within factor 2

*

Page 10: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

10-product parameter model5 scenarios:

◦ OH (low and high-NOx )◦ O3 (low and high-NOx ) ◦ NO3 (high-NOx)

Products fit to full model simulations with ageing

Diurnal cycle for VOC, OH, HO2 and O3 ; deposition

SOA equilibrium after 12 days

APOHHO22' APOHHO21' HO APINOHO2

NO APOHNO2' APOHNO1' NO APINOHO2APINOHO2 OH APIN

432

221

Page 11: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Two-product model parameterizations Odum (1996)

Y : SOA mass yield M0 : absorbing organic mass αi : mass stoichiometric coefficient of product i Ki : Pankow (1994) absorption equilibrium constant

i i

ii

MKKMY

00 1

gasi

aerii CM

CK

,0

,

.

Page 12: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Temperature dependence of parameters

Absorption equilibrium constant:

Stoichiometric coefficient )())11(exp()()()( ,,

rr

i

rripip m

mTTR

HTTTKTK

))298(exp()( 10 TT iii 0°C

30°C

Page 13: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

10-product model parameters

)())11(exp()()()( ,,rr

i

rripip m

mTTR

HTTTKTK

))298(exp()( 10 TT iii

0i 1

i )298(,ipK iHscenario product m3 µg-1 kJ mol-1

α-pinene + OH, low NOx

1 0.307 -0.022 6.98 85.62 0.211 -

0.01350.117 22.2

α-pinene + OH, high NOx

3 0.028 -0.040 0.762 132.24 0.109 -0.025 0.0048

685.3

α-pinene + O3, low NOx

5 0.282 -0.0132

4.155 86.8

6 0.142 -0.025 0.0158 77.1α-pinene + O3,

high NOx 7 0.016 -0.057 0.837 161.88 0.213 -

0.00540.0032

6111.4

α-pinene + NO3 high NOx

9 0.018 -0.049 0.493 172.410 0.251 -0.015 0.00092 147.6

i i

ii

MKKMY

00 1

APOHHO22' APOHHO21' HO APINOHO2

NO APOHNO2' APOHNO1' NO APINOHO2APINOHO2 OH APIN

432

221

APO3HO22' APO3HO21' HO APINO3O2

NO APO3NO2' APO3NO1' NO APINO3O2APINO3O2 O APIN

872

265

3

Reactions

APNO32.' APNO31' NO APIN 1093

OA

pineneii MW

MWTT ).()('

Page 14: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

10-product model curves at 298K

More SOA in low-NOx than in high-NOx (factor 8 difference)

α-pinene + OH leads to more SOA than α-pinene + O3

Page 15: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Why more SOA in low than high-NOx ?

++ O2

OH OHO O

+ NO

OHO NO210%

+ NO 90%OH

O

decomposition

OO

pinonaldehyde

+ HO2

OHO OH

++ O2

OH

O

OHO OH

O

+ HO2

O

OHO OH

OH

O2

OH++

OO

O O

NONO2+ +O

O

O ON O

O CH2

O + CO2

High-NOx

Low-NOx

Hydroperoxides (condensable)

Peroxy acyl nitrates

nitrates

More decompositionsMore volatile products

Page 16: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Verification at intermediate NOx

Full modelparameter model(modified)

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Sensitivity to photolysis and oxidants

Not accounting for photolysis of SOA during ageing Accumulation of condensables very high

yields Not very sensitive to chosen OH or HO2

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Comparison with other parameterizations

Low-NOx : Yields in this

study are higher than for others, ◦ Aging impact◦ Very low-NO x

But, also high yields in

Ng et al. (2007)

High-NOx : similar to Presto

et al. (2005)

T = 298 K

Page 19: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

SummaryBOREAM simulations of smog chamber photo-

oxidation: most SOA yields within factor 2Some overestimations for low-NOx

10-product model fit to explicit box model BOREAM including aging

Low-NOx SOA higher than previous parameterizations based on smog chambers (impact aging)

Photolysis of compounds in aerosol phase important

EVAPORATION: New vapour pressure estimation method

Page 20: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

Thank you for your attention!

Page 21: Parameterization of SOA formation  for  α- pinene , based on a detailed mechanism

α-pinene + O3 and pinonaldehyde chemistry