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Role of Glyoxal in SOA Formation from Aromatic Hydrocarbons

Role of Glyoxal in SOA Formation from Aromatic Hydrocarbons. SHUNSUKE NAKAO , Yingdi Liu, Ping Tang, Chia-Li Chen, David Cocker AAAR 2011 Orlando, FL Oct.6 (Thu) 10E.5. Role of glyoxal in aromatic SOA formation. SOA: Secondary Organic Aerosol. SOA formation from glyoxal.

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Role of Glyoxal in SOA Formation from Aromatic Hydrocarbons

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  1. www.cert.ucr.edu Role of Glyoxal in SOA Formation from Aromatic Hydrocarbons SHUNSUKE NAKAO, Yingdi Liu, Ping Tang, Chia-Li Chen, David Cocker AAAR 2011 Orlando, FL Oct.6 (Thu) 10E.5

  2. Role of glyoxal in aromatic SOA formation SOA: Secondary Organic Aerosol

  3. SOA formation from glyoxal • Cloud and fog processing • Aqueous oxidation (Tan et al., 2009) • Evaporating droplet(Leoffler et al., 2006; De Haan et al., 2009) • “Missing sink”  uptake onto aerosol • 15% of SOA formation in Mexico city (Volkamer et al., 2007) • Uptake onto wet (NH4)2SO4 • SO42- enhances Henry’s law constant (Ip et al., 2009) • Catalytic effect of NH4+ on oligomerization (Nozière et al., 2009) • Chamber studies (Jang and Kamens, 2001; Kroll et al., 2005; Liggio et al., 2005; Galloway et al., 2009, 2011; Volkamer et al., 2009) • Uptake onto organic seed • Fulvic acid, humic acid sodium salt, amino acids, carboxylic acids (Corrigan et al., 2008; Volkamer et al., 2009; De Haan et al., 2009)

  4. SOA formation from aromatics Glyoxal inferred to play a major role in aromatic-SOA • Glyoxal significant product: • 8~24% from toluene (with NOx, Calvert et al., 2002) • Oligomer formation (Kalberer et al., 2004) • Water effect: • Cocker et al., 2001  no effect (RH2~50%) • Edney et al., 2000  no effect (RH 52~70%) • Zhou et al., 2011  2~3 fold increase • (RH 10~90%, ascribed to glyoxal) RH 40~50% Kalberer et al., Science, 2004 This study: synthesized glyoxal, added glyoxal into aromatic-SOA system, and evaluated its impact

  5. Experimental Blacklights Dual teflon reactor Dual SMPS APM TDMA AMS PTRMS • Glyoxal synthesis - Heating glyoxal trimer dihydrate / P2O5 mixture under vacuum (Galloway et al., 2009, ACP) • Gas Phase Analysis Glyoxal, NO2 – CEAS (Cavity Enhanced Absorption Spectrometer) GC-FID– hydrocarbon O3,NOXanalyzer • Particle Phase Analysis SMPS– volume concentration and size distribution (Scanning Mobility Particle Sizer) V/H-TDMA–volatility/hygroscopicity (Volatility/hygroscopicity Tandem Differential Mobility Analyzer) HR-ToF-AMS– bulk chemical composition (Aerodyne High Resolution Time-of-Flight Mass Spectrometer)

  6. Glyoxal uptake onto wet (NH4)2SO4 RH~65% RunID: EPA1369A Glyoxal uptake confirmed(reversible oligomerization, Galloway et al., 2009; wall-reservoir, Loza et al., 2010)

  7. Glyoxal and SOA formation from toluene/NOx photooxidation NO: 42 ppb RH 40% RunID: EPA1503A Solid line: model prediction by SAPRC11(Poster 5E.8)

  8. Additional 80ppb glyoxal Kinetic effect Effect of additional glyoxal on toluene SOA formation NOx: ~40ppb RH ~70% + H2O2 + glyoxal

  9. No glyoxal uptake onto “aromatic-SOA seed” Shaded area: dark No contribution from glyoxal during/after SOA formation

  10. ~10-5 Pa ~10-7 ~10-6 ~10-8 Thermodenuder vaporization profiles Glyoxal oligomer & aromatic SOA low volatile (<<10-8 Pa) Aromatic SOA Residence time: ~15 sec Faulhaber et al., AMT, 2009

  11. Volatility evolution

  12. Non-seeded vs (NH4)2SO4 seed Toluene + NOx (RH~70%)

  13. 2-tert-butylphenol(BP) • Tert-butyl AMS fragment (C4H9+)  tracer for BP SOA

  14. Enhanced SOA formation by glyoxal without glyoxal oligomerization Higher SOA without decrease in C4H9 fraction 2t-BP (100ppb) + H2O2 (250ppb) RH 51% Added glyoxal ~ 1ppm

  15. Conclusion • Glyoxal reactive uptake onto wet (NH4)2SO4 confirmed • No significant glyoxal uptake onto toluene SOA was observed • Addition of glyoxal/H2O2 resulted in same PM formation and PM volatility • Addition of glyoxal after PM formation (dark, SOA seed) did not form SOA • Presence of (NH4)2SO4 seeds did not impact SOA yield significantly • Addition of glyoxal did not alter fC4H9 of 2-tert-BP SOA • The role of glyoxal in this chamber study was observed to be a radical source; insignificant contribution of reactive uptake was observed. • Glyoxal uptake onto “SOA seed” needs to be evaluated

  16. Acknowledgements Graduate advisor: Dr. David Cocker Current/former students: Christopher Clark, Ping Tang, Xiaochen Tang, Dr. Quentin Malloy, Dr. Li Qi, Dr. Kei Sato Undergraduate student: Sarah Bates Support staff: Kurt Bumiller, Chuck Bufalino Glyoxal synthesis: Dr. Melissa Galloway, Dr. Arthur Chan Funding sources: NSF, W.M. Keck Foundation, and University of California, Transportation Center www.cert.ucr.edu 16

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