Tzung-May Fu, Daniel J. Jacob Department of Earth and Planetary Sciences Harvard University

1. Global Budgets of Atmospheric Glyoxal and Methylglyoxal and Implications for Formation of Secondary Organic Aerosols CHOCHO (glyoxal) Tzung-May Fu, Daniel J. Jacob Department of Earth and Planetary Sciences Harvard University CH3C(O)CHO (methylglyoxal) Folkard Wittrock, John P. Burrows, Mihalis Vrekoussis Institute of Environmental Physics and Remote Sensing University of Bremen US EPA November 8 2007 Fu et al. [2007b] submitted This work is supported by EPRI

2. Organic Aerosols: Primary vs. Secondary Primary Organic Aerosols (POA) Secondary Organic Aerosols (SOA) Nucleation Reversible partitioning on existing particles Direct emission Semi-volatile organic gases FF: 45-80 TgC y-1 BB: 10-30 TgC y-1 Oxidation by OH, O3, NO3 Isoprene Terpenes Aromatics Fossil fuel burning Biomass burning ANTHROPOGENIC SOURCES BIOGENIC SOURCES

3. Mean Observations Mean Simulation (GEOS-Chem global CTM) Observations + ACE-Asia: OC aerosol measurements in the free troposphere (ACE-Asia aircraft campaign conducted off of Japan April/May 2001) [Mader et al., 2002] [Huebert et al., 2003] [Maria et al., 2003] Heald et al. [2005], GRL Concentrations of OC in the FT were under-predicted by a factor of 10-100 Current knowledge is missing a large SOA source c/o Colette Heald

4. Where is the large missing SOA source? Volkamer et al. [2006] Secondary Organic Aerosols (SOA) SOAobs / SOAmodel Nucleation Reversible partitioning on existing particles Semi-volatile organic gases Oxidation by OH, O3, NO3 Isoprene 400 Tg y-1 Terpenes Aromatics ANTHROPOGENIC SOURCES BIOGENIC SOURCES

5. SOA formation by reactive uptake of dicarbonyls Isoprene (400 Tg y-1), monoterpenes, acetone, MBO, C2H4, C3H6 Our goal: build global model OH, O3, NO3 t~ 2.9 hr Irreversible uptake? glyoxal methylglyoxal SOA Acetone, C2H2, isoalkanes, alkenes, aromatics, glycolaldehyde, hydroxyacetone, primary emissions Oligomers? organic acids? t ~ 1.6 h Photolysis Oxidation Deposition Fu et al. [2007b]

6. Oligomers Kalberer et al. [2004] Liggio et al. [2005] Hastings et al. [2005] Zhao et al. [2006] Loeffler et al. [2006] 1 + hydrates + H2O 3 Altieri et al. [2006] + OH ? 2 Organic acids Ervens et al. [2004] Lim et al. [2005] Carlton et al. [2006, 2007] Warneck et al. [2005] Sorooshian et al. [2006] What are the irreversible processes in the AQ phase? H* ~ 105 H2O H2O H* ~ 103

7. First detailed global simulation of glyoxal and methylglyoxal Isoprene (400 Tg y-1), monoterpenes, acetone, MBO, C2H4, C3H6 Built on GEOS-Chem global 3D CTM OH, O3, NO3 lifetime ~ 2.9 hr Irreversible uptake glyoxal methylglyoxal SOA Acetone, C2H2, isoalkanes, alkenes, aromatics, glycolaldehyde, hydroxyacetone, primary emissions lifetime ~ 1.6 hr Photolysis Oxidation Deposition Fu et al. [2007b]

8. New isoprene oxidation adapted from MCM v3.1 Fu et al. [2007b] Isoprene + OH  0.046 Glyoxal + 0.16 Glycolaldehyde + 0.13 Methylglyoxal + 0.15 Hydroxyacetone

9. Biogenic Biomass burning Biofuel use Anthropogenic Result: Sources of glyoxal and methylglyoxal Glyoxal 45 Tg y-1 Methylglyoxal 140 Tg y-1 1 Isoprene is largest source for both glyoxal (47%) and methylglyoxal (79%). 2 Second largest sources C2H2 and acetone  long lifetime  dicarbonyl background 3 Glyoxal is more sensitive to non-biogenic emissions (79%) (47%) Fu et al. [2007b]

10. Result: Photolysis is the dominant sink of dicarbonyls Glyoxal Methylglyoxal Burden: 15 Gg 25 Gg 1.6 hours 1 Photolysis is the dominant sink for both dicarbonyls 2 SOA formation must compete against photolysis and oxidation 3 90% of SOA formation is in clouds Lifetime: 2.9 hours Photolysis Oxidation SOA formation Dry deposition Wet deposition Sink: 45 Tg y-1 140 Tg y-1 Fu et al. [2007b]

11. Simulated global concentrations of glyoxal 2 Northern mid-latitude summertime model glyoxal ~ 10-100 ppt 1 Biomass burning: highest surface concentration 3 Acetylene: hemispheric background and anthropogenic outflow Fu et al. [2007b]

12. Simulated global concentrations of methylglyoxal 2 Northern mid-latitude summertime model methylglyoxal ~ 20-150 ppt, w/ stronger biogenic pattern 1 Biomass burning: highest surface concentration 3 Acetone: global background and anthropogenic outflow Fu et al. [2007b]

13. Simulated dicarbonyl concentrations are consistent with available in situ measurements Glyoxal Methylglyoxal Northern mid-latitudes (summer) Marine boundary layer Free troposphere 1 Northern mid-latitudes summertime dicarbonyl concentrations consistent with measurements 2 Marine boundary layer  model underestimates dicarbonyls? Fu et al. [2007b]

14. 1~3.5 x1014 molec cm-2 0.5~2 x1014 molec cm-2 Simulated glyoxal pattern consistent w/ satellite over land SCIAMACHY GEOS-Chem Wittrock et al. [2006a,b] Overall error ~ 4 x 1014 molec cm-2 Over land: simulated glyoxal column pattern agrees well with satellite observations, but model concentrations are 50% lower Satellite product has error ~ 4 x 1014 molec cm-2 and issues with clouds [Wittrock et al., 2006b] Fu et al. [2007b]

15. MODIS chlorophyll 2006 Is there a large unknown marine source of glyoxal? SCIAMACHY GEOS-Chem Wittrock et al. [2006a] Over tropical ocean: satellite retrieve high glyoxal column  interference by chlorophyll?  unknown marine emissions or precursors? Fu et al. [2007b]

16. Dicarbonyls produce large amounts of SOA! 11 9.0 20% 6.7 Glyoxal 2.6 Methyl-gyloxal 8.0 Annual SOA source [Tg C y-1] 1.8 Anthropogenic Biofuel use Biomass burning Biogenic Reversible partitioning Irreversible uptake by aerosol (10%) and clouds (90%) Fu et al. [2007b] SOA production via irreversible uptake of dicarbonyls  comparable to SOA production from reversible partitioning

17. Are the reversible / irreversible production of SOA from isoprene oxidation products additive? It is unclear, BUT Kroll et al. [2006], Surrat et al. [2006] Methacrolein SOA from reversible partitioning (methylglyoxal) Isoprene X Methyl vinyl ketone (glyoxal and methylglyoxal) Experiments conducted at RH < 10%  no aqueous reaction

18. CHOCHO Isoprene is the largest source of dicarbonyls + CH3COCHO Irreversible uptake 20% of SOA produced via dicarbonyls are from non-biogenic emissions, especially in FT Major findings : Global budgets of dicarbonyls and their SOA production Current simulated SOA sources from biogenic terpenes (9 Tg C y-1), isoprene (7 Tg C y-1) and aromatics are too small! Isoprene, monoterpenes, acetone, MBO, C2H4, C3H6 SOA production from dicarbonyls 11 Tg C y-1 OH, NO3, O3 Acetone, C2H2, isoalkanes, alkenes, aromatics, glycolaldehyde, hydroxyacetone, primary emissions Fu et al. [2007b]

19. Contribution of dicarbonyl SOA in U.S. Aircraft measurements during ICARTT (summer 2004) Water Soluble Organic Carbon by Rodney Weber at Georgia Tech Samples influenced by biomass burning removed Observed WSOC Model w/ dicarbonyl SOA Model w/o dicarbonyl SOA Model w/ dicarbonyl SOA Model w/o dicarbonyl SOA Observed WSOC Altitude [km] [mg C m-3 STP] WSOC [mg C m-3 STP]

20. WSOC correlation with other measured tracers Observed WSOC Model WSOC including SOA from dicarbonyl Model WSOC without SOA from dicarbonyls ICARTT WP3 measurements in FT (2 to 6 km), without biomass burning samples Dicarbonyl SOA • captures a lot of the observed variation • correlates with sulfate (aqueous processes) and toluene (anthropogenic precursors) Correlation coefficient (r)

21. WSOC production in cloud – need regional model Measurements on Twin Otter during ICARTT (summer 2004) Sorooshian et al. [2006] Oxalate SO4 NH4 NO3 Power plant plume in clouds Measured oxalate consistent with toluene being precursor Oxalate [nmol m-3] SO4 [nmol m-3]

22. Using suite of satellite observations to diagnose regional pollutant emission and chemistry NO2 June 2005 Glyoxal June 2005 SO2 June 2005 c/o T. Kurosu c/o KNMI c/o KNMI Volkamer et al. [2006] HCHO Glyoxal NO2 July 25 2005 July 26 2005 July 27 2005