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Global simulation of glyoxal and methylglyoxal, and implications for SOA

CHOCHO. Global simulation of glyoxal and methylglyoxal, and implications for SOA. CH 3 C(O)CHO. Tzung-May Fu, Daniel J. Jacob Harvard University. Thomas Kurosu, Kelly Chance Harvard/SAO CfA. April 11, 2007 Work supported by EPRI. SOA formation through uptake of dicarbonyls.

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Global simulation of glyoxal and methylglyoxal, and implications for SOA

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  1. CHOCHO Global simulation of glyoxaland methylglyoxal,and implications for SOA CH3C(O)CHO Tzung-May Fu, Daniel J. Jacob Harvard University Thomas Kurosu, Kelly Chance Harvard/SAO CfA April 11, 2007 Work supported by EPRI

  2. SOA formation through uptake of dicarbonyls Isoprene (350 Tg C yr-1), monoterpenes, acetone, MBO, C2H4, C3H6 [OH] RH pH nuclei OH, O3, NO3 H* ~ 105 Reversible? CHOCHO CH3C(O)CHO SOA C2H2, C2H4, C3H6, aromatics, acetone, glycolaldehyde, hydroxyacetone H* ~ 103 Oligomers? organic acids? Photolysis Oxidation Deposition

  3. Reversible Irreversible [Glyx]g = 200 ppb Time  [Kroll et al., 2005] g = 2. x 103 KH* = 2.6 x 107 M atm-1 For [Glyx]g = 0.1 ppb, ∆[Glyx]particle = 3 mg m-3 hr-1 For [Glyx]g = 0.1 ppb, [Glyx]particle = 0.003 mg m-3 Is dicarbonyl uptake irreversible? Organic/sulfate [mg mg-1] Organic / sulfate [g/g] [Glyx]g = 5 ppb [Liggio et al., 2005b]

  4. Oligomers Kalberer et al. [2004] Liggio et al. [2005] Hastings et al. [2005] Zhao et al. [2006] 1 + hydrates + H2O 3 Altieri et al. [2006] + OH ? 2 Organic acids Ervens et al. [2004] Lim et al. [2005] Warneck et al. [2005] Sorooshian et al. [2006] What are the irreversible processes in the aqueous phase? H* ~ 105 H2O H2O H* ~ 103

  5. GEOS-Chem v736 4x5 2005/12 – 2006/11 (GEOS4) Tracers emitted, non-standard • ISOP, MONX, MBO, C2H4, PRPE, C2H2, ACET, HAC, BENZ, TOLU, XYLE, GLYX, MGLY, GLYC, MVK, MACR, PAN, PMN, ACRPAN, ENPAN, GPAN, GLPAN, MPAN, NIPAN Chemistry • New chemical mechanism from MCM v3.1, University of Leeds • JPL 2006 rate constants and photolysis (p-dependent) • Standard SOA from BVOC • Reactive uptake of dicarbonyls by aqueous aerosol and cloud droplets [Liggio et al., 2005b; Zhao et al., 2006] Standard emissions • FF + BF: GEIA + regional • BB: GFED2 • BG: MEGAN Non-standard emissions • FF + BF for C2H2: Xiao et al. [2007] • FF + BF for C2H4, arom.: RETRO • BB: Scale GFED2 CO w/ EFs • BG: MEGAN Dry/wet deposition: • GLYX, MGLY, GLYC, PANs

  6. New isoprene oxidation – adapted from MCM v3.1 ISOP 0.3h OH, O3 OH NO3 IALD MVKOH NIALD MVK MACR 0.7h 1.5h 0.7h 2h 1h GLYX GLYC MGLY HAC 1.5h 1h 9.8h 2.7h High NOx, no RO2 recycling ISOP + OH  0.045 GLYX + 0.508 GLYC + 0.233 MGLY + 0.197 HAC + 1.033 CH2O Production of glyoxal Larger yield of methgylglyoxal, GLYC, HAC Larger yield of CH2O

  7. Are the two Isoprene  SOA pathways additive? SOA via irreversible uptake of glyoxal from isoprene SOA via partitioning of semi-volatile products from isoprene Mechanism from MCM v3.1 (U of Leeds) Experiments by [Kroll et al., 2006] YGLYX ~ 10 % at high [NOx] YGLYX < 5 % at low [NOx] Y = 1~2 % at high [NOx] Y = 3 % at low [NOx] Methyl vinyl ketone is an important intermediate Methacrolein is an important intermediate Two pathways of SOA formation from isoprene are additive

  8. C2H4 oxidation – from MCM v3.1 Parameterized chemistry High NOx C2H4 + OH  0.995 [a GLYC + (1-a) ∙ 2 HCHO + HO2], a = 0.3 ~ 1 C2H2 + OH  0.636 GLYX MONX + O3  0.05 GLYX + 0.05 MGLY MBO + OH  0.63 GLYC + (0.63 ACET) BENZ + OH  0.252 GLYX TOLU + OH  0.162 GLYX + 0.124 MGLY XYLE + OH  0.156 GLYX + 0.230 MGLY (0.16 - 0.29) (0.08 - 0.39) (0.03 - 0.18) (0.11 - 0.42) (0.03 – 0.40)

  9. Monthly mean [GLYX], Jul 2006 @ sfc @ 2 km ~ 10-2 ppb 10-1 ~ 10-2 ppb [ppb] [ppb]

  10. Monthly mean [MGLY], Jul 2006 @ sfc @ 2 km ~ 10-2 ppb 10-1 ~ 10-2 ppb [ppb] [ppb]

  11. Tomakomai Forest, Japan Sep 2003 [ppt] Ieda et al. [2006] BlodgettForest, CA Aug-Sep 2000 Spaulding et al. [2003] Hourly mean [MGLY], [GLYX] [ppt] Local time [h]

  12. Comparison with SCIAMACHY [Wittrock et al., 2006] GLYX VC Dec05-Nov06 (12-15LT) SCIAMACHY GLYX VC (10LT) HCHO VC Dec05-Nov06 SCIAMACHY HCHO VC

  13. SOA from monoterpenes etc SOA from isoprene (Yisop = 1~3%) SOAglyx+SOAmgly @ surface 30% 12% 58% P ~ 10 Tg yr-1 P ~ 6 Tg yr-1 Pglyx ~ 12 + 6 Tg yr-1 Pmgly ~ 21 + 17 Tg yr-1 [ug m-3] @ 4.2 km 27% 23% 50% [0.1 ug m-3]

  14. Conclusions I. Global simulation of glyoxal and methylglyoxal • Model sfc concentration same order as rural measurements • Model glyoxalVC <~ satellite VC measurements • Isoprene oxidation products well simulated w/ new mechanism • Isoprene is the largest source  dicarbonyls in the free troposphere • Direct emissions from biomass burning  large surface concentrations II. Reactive uptake of dicarbonyls is significant SOA source • Produces > 18 Tg yr-1 SOA, comparable to other biogenic SOA sources • SOA from isoprene via glyoxal is independent of SOA from isoprene via semi-volatile gaseous products • Anthropogenic and biomass burning emissions produce significant SOA via uptake of dicarbonyls

  15. WHAT DON’T WE UNDERSTAND ABOUT SOA FORMATION? Cloud Processing CHEMISTRY 1. NOx, SO2/acidity 2. Multi-step oxidation SOA: >20 Tg/yr FORMATION PATHWAYS OC Nucleation or Condensation dicarbonyls Heterogeneous Reactions PRECURSORS Oxidation by OH, O3, NO3 FF: 45-80 TgC/yr BB: 10-30 TgC/yr Terpenes Isoprene Aromatics Direct Emission Fossil Fuel Biomass Burning ANTHROPOGENIC SOURCES BIOGENIC SOURCES C/o Colette Heald

  16. “Reactive uptake of dicarbonyl” is an attractive mechanism, because it … • is a sustained SOA source in aged air masses and free troposphere • works for both biogenic and anthropogenic precursors • takes place rapidly in clouds, consistent with field evidence • produces SOA quickly near the source region. Diurnal variations of SOA concentration more similar to measurements with maximum concentration in the afternoon • may explain large, heterogeneous source of oxalic acid in aerosols • may explain observed oligomers in aerosols

  17. Experiments needed to determine … • Photolysis quantum yield in the visible band • Reversibility of uptake • Uptake sensitivity to pH • Uptake sensitivity to ionic strength • Total mass contribution of oligomers • Presence/ID of organic acid hydrate oligomers • Consistency with ambient aerosol mass spectra

  18. Pabstthum, Germany Jul-Aug 1998 Grossmann et al. [2003] Hourly mean [MGLY], [GLYX] [ppt] Local time [h] Mexico City Apr 2003 Volkamer et al. [2005b]

  19. GEOS-ChemAug-Sep 2006 Blodget Forest, CAAug-Sep 2000 Local time [h] Spaulding et al. [2003]

  20. Isoprene oxidation – GEOS-Chem ISOP 0.3h OH, O3, NO3 OH IALD MVK MACR 2h 1h 0.8h GLYX GLYC MGLY HAC 1.5h 1h 9.8h 2.7h High NOx, no RO2 recycling ISOP + OH  0.317 GLYC + 0.198 MGLY + 0.158 HAC + 0.969 CH2O No glyoxal production from isoprene

  21. Volkamer et al. [2006] ORGANIC CARBON AEROSOL *Numbers from IPCC [2001] Secondary Organic Aerosol (SOA): 8-40 TgC/yr Goldstein and Galbally [2007] 510-910 TgC/yr Partitioning of semivolatile gas? Heterogeneous rxn of soluble gas? Other mechanisms? Reactive Organic Gases OC Nucleation or Condensation • Global Model Representation of SOA: • “Effective primary” yield of semivolatile gas • Two-product empirical fit to smog chamber data Oxidation by OH, O3, NO3 FF: 45-80 TgC/yr BB: 10-30 TgC/yr Monoterpenes, etc Aromatics Isoprene 350 TgC/yr Direct Emission Fossil Fuel Biomass Burning ANTHROPOGENIC SOURCES BIOGENIC SOURCES C/o Colette Heald

  22. [Glyoxal] in ambient air Rural 10-1 ~10-2 ppb Remote and FT 10-1 ~ 10-2 ppb

  23. [Methyglyoxal] in ambient air Rural >1 ~10-2 ppb Remote and FT ~ 10-2 ppb

  24. What are the irreversible processes in the aqueous phase? • I. Hydrate + OH •  glyoxylic acid, pyruvic acid • Oxalic acid • II. Hydrate + H2O • Oligomers Ervens et al. [2004]; Lim et al. [2005]; Warneck et al. [2005]; Sorooshian et al. [2006] Kalberer et al. [2004]; Liggio et al. [2005]; Hastings et al. [2005]; Zhao et al. [2006]

  25. III. Hydrate + OH • glyoxylic acid, pyruvic acid  oligomers • oxalic acid  oligomers T = 10 min T = 202 min Altieri et al. [2006]

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