1 role of glyoxal in soa formation from aromatic hydrocarbons shunsuke nakao, yingdi liu, ping...
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Role of Glyoxal in SOA Formation from Aromatic Hydrocarbons
SHUNSUKE NAKAO, Yingdi Liu, Ping Tang, Chia-Li Chen, David Cocker
AAAR 2011Orlando, FLOct.6 (Thu)
10E.5
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Role of glyoxal in aromatic SOA formation
SOA: Secondary Organic Aerosol
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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 • SO4
2- 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)
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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)
This study: synthesized glyoxal, added glyoxal into aromatic-SOA system, and evaluated its impact
Kalberer et al., Science, 2004RH 40~50%
Experimental • 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, NOX analyzer
• 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)
Dual SMPS
Blacklights
Dual teflon reactor
APMTDMA
PTRMSAMS
Glyoxal uptake onto wet (NH4)2SO4
Glyoxal uptake confirmed(reversible oligomerization, Galloway et al., 2009; wall-reservoir, Loza et al., 2010)
RH~65%RunID: EPA1369A
50
40
30
20
10
0
Gly
oxal
(pp
b)
86420
Uptake time (hour)
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Organic/S
ulfate
500
400
300
200
100
0
Perfluorohexane (ppb)
Glyoxal Org/sulfate Tracer
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Glyoxal and SOA formation from toluene/NOx photooxidation
Solid line: model prediction by SAPRC11(Poster 5E.8)
NO: 42 ppbRH 40%RunID: EPA1503A
100
80
60
40
20
0
To
lue
ne (
ppb
)
1086420Hours after lights on
30
25
20
15
10
5
0
Glyoxal (p
pb)
50
40
30
20
10
0
Vo
lume
conce
ntration (
m3/cm
3)
Toluene Volume Glyoxal Glyoxal - model
0.10
0.08
0.06
0.04
0.02
0.00
Tol
uene
(pp
m)
1086420Hours after lights on
100
80
60
40
20
0
PM
Volum
e concentration (m
3/cm3)
Effect of additional glyoxal on toluene SOA formation
Kinetic effect
Additional 80ppb glyoxal
NOx: ~40ppbRH ~70%
+ glyoxal
+ H2O2
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140
120
100
80
60
40
20
0
Gly
oxal
(pp
b)
121086420
Hours after lights on
100
80
60
40
20
0
PM
volume (
m3/cm
3)
Glyoxal Volume (suspended) Volume (wall-corrected)
No glyoxal uptake onto “aromatic-SOA seed”
No contribution from glyoxal during/after SOA formation
Shaded area: dark
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Glyoxal oligomer
Vol
ume
Fra
ctio
n R
emai
ning
16014012010080604020
Decanedioic acid Hexanedioic acid
Thermodenuder vaporization profiles
Glyoxal oligomer & aromatic SOA low volatile (<<10-8 Pa)
Aromatic SOA
~10-6~10-5
Pa~10-7
~10-8
Faulhaber et al., AMT, 2009
Residence time: ~15 sec
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Volatility evolution1.0
0.8
0.6
0.4
0.2
0.0
Vol
ume
Fra
ctio
n R
emai
ning
@10
0C
121086420Hours after lights on
Toluene + NOx (humid) Toluene + NOx + glyoxal (humid)
Toluene + NOx + H2O2 (humid)
12
100
80
60
40
20
0
Pa
rtic
le v
olum
e (m
3 /cm
3 )
250200150100500
Hydrocarbon reacted (g/m3)
non-seeded non-seeded non-seeded
Toluene + NOx (RH~70%)
Non-seeded vs (NH4)2SO4 seed
(NH4)2SO4 seed (NH4)2SO4 seed (NH4)2SO4 seed (NH4)2SO4 seed
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2-tert-butylphenol(BP)
• Tert-butyl AMS fragment (C4H9+)
tracer for BP SOA
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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
12
8
4
0
Vo
lum
e c
on
cen
tra
tion
(m
3/c
m3)
121086420Hours after lights on
0.20
0.15
0.10
0.05
0.00
fC4 H
9
add glyoxal Vol
C4H9+
Conclusion
• 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
• 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
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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