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

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 One proposed pathway of SOA growth via uptake of soluble gas is through dicarbonyl OBS have measured large amounts of carbonyl in automobile exhaust, urban aerosols, etc Glyoxal is the most abundant dicarbonyl in the atmosphere Produced by the oxidation of biogenic isoprene. And acetylene, aromatics, and ethene, which are mostly anthropogenic. Removed by photolysis, oxidation, and deposition Very soluble species To date there are a number of lab measurements of glyoxal in aerosols. It has also been shown to form oligomers in the aerosol So then, is the uptake irreversible? Oxidation by OH, O3, NO3 Isoprene Terpenes Aromatics Fossil fuel burning Biomass burning BIOGENIC SOURCES ANTHROPOGENIC SOURCES

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] Mean Observations Mean Simulation (GEOS-Chem global CTM) Observations + 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

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 One proposed pathway of SOA growth via uptake of soluble gas is through dicarbonyl OBS have measured large amounts of carbonyl in automobile exhaust, urban aerosols, etc Glyoxal is the most abundant dicarbonyl in the atmosphere Produced by the oxidation of biogenic isoprene. And acetylene, aromatics, and ethene, which are mostly anthropogenic. Removed by photolysis, oxidation, and deposition Very soluble species To date there are a number of lab measurements of glyoxal in aerosols. It has also been shown to form oligomers in the aerosol So then, is the uptake irreversible? Oxidation by OH, O3, NO3 Isoprene 400 Tg y-1 Terpenes Aromatics BIOGENIC SOURCES ANTHROPOGENIC SOURCES

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 glyoxal Irreversible uptake? methylglyoxal SOA Acetone, C2H2, isoalkanes, alkenes, aromatics, glycolaldehyde, hydroxyacetone, primary emissions Oligomers? organic acids? One proposed pathway of SOA growth via uptake of soluble gas is through dicarbonyl OBS have measured large amounts of carbonyl in automobile exhaust, urban aerosols, etc Glyoxal is the most abundant dicarbonyl in the atmosphere Produced by the oxidation of biogenic isoprene. And acetylene, aromatics, and ethene, which are mostly anthropogenic. Removed by photolysis, oxidation, and deposition Very soluble species To date there are a number of lab measurements of glyoxal in aerosols. It has also been shown to form oligomers in the aerosol So then, is the uptake irreversible? t ~ 1.6 h Photolysis Oxidation Deposition Fu et al. [2007b]

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

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 glyoxal Irreversible uptake methylglyoxal SOA Acetone, C2H2, isoalkanes, alkenes, aromatics, glycolaldehyde, hydroxyacetone, primary emissions lifetime ~ 1.6 hr One proposed pathway of SOA growth via uptake of soluble gas is through dicarbonyl OBS have measured large amounts of carbonyl in automobile exhaust, urban aerosols, etc Glyoxal is the most abundant dicarbonyl in the atmosphere Produced by the oxidation of biogenic isoprene. And acetylene, aromatics, and ethene, which are mostly anthropogenic. Removed by photolysis, oxidation, and deposition Very soluble species To date there are a number of lab measurements of glyoxal in aerosols. It has also been shown to form oligomers in the aerosol So then, is the uptake irreversible? Photolysis Oxidation Deposition Fu et al. [2007b]

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

Result: Sources of glyoxal and methylglyoxal Glyoxal 45 Tg y-1 Methylglyoxal 140 Tg y-1 (79%) (47%) Biogenic Biomass burning Biofuel use Anthropogenic Fu et al. [2007b] 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

Result: Photolysis is the dominant sink of dicarbonyls Glyoxal Methylglyoxal Burden: 15 Gg 25 Gg Lifetime: 2.9 hours 1.6 hours Photolysis Oxidation SOA formation Dry deposition Wet deposition Sink: 45 Tg y-1 140 Tg y-1 Fu et al. [2007b] 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

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]

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]

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]

Simulated glyoxal pattern consistent w/ satellite over land SCIAMACHY GEOS-Chem 1~3.5 x 1014 molec cm-2 0.5~2 x 1014 molec cm-2 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]

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

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

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

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 Isoprene is the largest source of dicarbonyls SOA production from dicarbonyls 11 Tg C y-1 CHOCHO + CH3COCHO Irreversible uptake OH, NO3, O3 Acetone, C2H2, isoalkanes, alkenes, aromatics, glycolaldehyde, hydroxyacetone, primary emissions O3 +VOC+NOx chemistry cartoon Biogenic vs anthropogenic Interaction with anthrpogenic NOx Ozone production OA production Climate impact 20% of SOA produced via dicarbonyls are from non-biogenic emissions, especially in FT Fu et al. [2007b]

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]

WSOC correlation with other measured tracers ICARTT WP3 measurements in FT (2 to 6 km), without biomass burning samples Observed WSOC Model WSOC including SOA from dicarbonyl Model WSOC without SOA from dicarbonyls Dicarbonyl SOA captures a lot of the observed variation correlates with sulfate (aqueous processes) and toluene (anthropogenic precursors) All model WSOC are based on tmf’s simulation of OCPI+SOAG+SOAM and clh’s SOA1+SOA2+SOA3+SOA4. The tmf simulation version is ‘tmf20’ – glyoxal production from isoprene about 30% too high. [tmf, 9/20/2007] Correlation coefficient (r)

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

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