powerpoint presentation | us epa archive document · barbara j. turpin. rutgers university. with...

Barbara J. TurpinRutgers University

With Contributions from:Annmarie

Carlton, Katye Altieri, Sybil Seitzinger, Barbara

Ervens, Ho‐Jin Lim, Yi Tan, Mark Perri

Secondary and Regional Contributions to Organic PM

Unit Name

Optional Presentation Title Dept of Environmental Sciences

ObjectiveConduct controlled laboratory experiments investigating

secondary organic aerosol (SOA) formation through cloud processing

In the Process• Consider whether experiments suggest “source tracers” or

“process indicators” to aid field investigations of SOA

• Examine Pittsburgh Supersite data for evidence of SOA formation through cloud processing

• Provide kinetic/mechanistic data needed to refine SOA models

Unit Name

Optional Presentation Title Secondary Organic Aerosol

In‐Cloud SOA Formation

Organic gases are oxidized (e.g., in interstitial spaces of clouds) to water-soluble compounds.

Water-soluble gases partition into cloud droplets and oxidize further (e.g., by ·OH formed photochemically).

Low volatility products remain in the particle phase upon cloud evaporation, contributing secondary organic aerosol (SOA), especially in FT

(Blando and Turpin, 2000; Gelencser and Varga, 2005)

organic gases, NOx…

Cloud evaporation SOA

In-cloud chemistry

Unit Name


Evidence for In‐Cloud SOA

Heald et al., 2005 (ICART): Organic PM concentrations in FT exceed current model predictions (i.e., without in-cloud SOA). Polidori et al., 2006 (Pittsburgh); Lim and Turpin, 2002 (Atlanta): Elevated ground level SOA with down-mixing of air from aloft.

Heald et al., 2006; Chebbi and Carlier, 1996; Yu et al., 2005; Kawamura et al., 1993: Concentration dynamics link oxalic acid with potential aqueous precursor aldehydes or with sulfate (formed through cloud processing).Sorooshian et al. 2006 (ICART); 2007(MACE); Crahan et al., 2004: In-cloud organic acid measurements/simulations suggest oxalic acid is formed through cloud processing.

Warneck, 2003; Ervens et al., 2004; Lim et al., 2005: predict in-cloud organic acids and SOA from emissions

Organic PM Concentrations Aloft

Oxalic Acid Concentration Dynamics

Cloud Chemistry Modeling

Unit Name

Optional Presentation Title

Lim Cloud Chemistry Model (to guide experiments):

Secondary Organic Aerosol

Phase transfersRxs with •OH

Aqueous phase

ISOPRENE + oxidants (·OH, O3 , NO3 )

HOCH2CHO CHOCHO CH3COCHO(glycolaldehyde) (glyoxal) (methylglyoxal)

HOCH2CH(OH)2 (OH)2CHCH(OH)2 CH3COCH(OH)2

HOCH2COOH CH3COCOOH(glycolic acid) (pyruvic acid)

(OH)2CHCOOH CH3COOH(glyoxylic acid - hydrated) (acetic acid)

HOOCCOOH CH2(OH)2(oxalic acid) (formaldehyde - hydrated)

CO2 HCOOH(formic acid)

Gas phase

67%

33% 92%8%

85%

15%

Lim et al., 2005

Unit Name


CH3COCHO(methylglyoxal)

CH3COCH(OH)2

CH3COCOOH(pyruvic acid)

CH3 COCOOH

CH3 COH

(acetaldehyde)

CH3 COH

Ervens

Model:

aqueous methylglyoxal

and pyruvic

acid photo‐oxidation does not form low volatility organic acids


Unit Name


Predicted In‐Cloud SOA Concentrations: (Ervens

et al., 2004; Lim et al., 2005)


10 – 25% of measured oxalic acid formed from aqueous reactions with methylglyoxal, glyoxal and glycolaldehyde(clean – polluted continental)

Oxalic acid remains mostly in the particle phase upon droplet evaporation, forming SOA.

Additional precursors

Additional low volatility organics

Aqueous photooxidation pathways/products largely assumed

Predicted products had not been verified experimentally

Unit Name


Objective:Validate and refine aqueous-phase reaction pathways and improve kinetics

Approach:Conduct aqueous-phase photooxidation experiments, measure products, model product formation

Organic + H2 O2 + UV (plus controls)

To provide supply of ·OH


Unit Name


Results:

Oxalic acid is formed from GLY, MG, PA

*Typical cloud/fog pH 2-5; Catalase to stop reactions; Samples frozenCarlton et al., 2006; Altieri et al., 2006; Carlton et al (2007)

Organic

Conc.(N)H2 O2pH*

Glyoxal

2 mM(3)10 mM4.1 - 4.8

Methylglyoxal

2 mM(3)10 mM4.2 – 4.5

Pyruvic Acid

10 mM(3)20 mM2.7

Experiment ORG+UV+H2 O2

UV Control ORG+ H2 O2

H2 O2 Control ORG+UV

Organic Control

UV+H2 O2

Unit Name


Pyruvic

Acid Results:


Phase transfersRxs with •OH

Aqueous phase

ISOPRENE + oxidants (·OH, O3 , NO3 )

HOCH2CHO CHOCHO CH3COCHO(glycolaldehyde) (glyoxal) (methylglyoxal)

HOCH2CH(OH)2 (OH)2CHCH(OH)2 CH3COCH(OH)2

HOCH2COOH CH3COCOOH(glycolic acid) (pyruvic acid)

(OH)2CHCOOH CH3COOH(glyoxylic acid - hydrated) (acetic acid)



Gas phase

67%

33% 92%8%

85%

15%

Carlton et al., 2006

Unit Name


m/z0 100 200 300 400 500 600

Ion

Abun

danc

e (a

rbitr

ary

units

)

0

100000

200000

300000

400000

500000

600000

89

87

73

175

Electrospray

Ionization Mass Spectrum (ESI‐MS): Mixed Standard of Pyruvic

Acid and Predicted Products

Pyruvic

Glyoxylic

Oxalic

Pyruvic


ESI: soft ionization, does not

fragment

positive mode protonates

cmpds

with basic functional

groups MW+1

negative deprotonates

cmpds

with acidic functional groups

MW‐1

Unit Name


m /z

0 100 200 300 400 500 600

Ion

Abu

ndan

ce (a

rbitr

ary

units

)

0

50000

150000

200000

250000

300000

89

103

133

147

177

217

m /z

200 210 220 230 240 250

Ion

Abu

ndan

ce

0

10000

20000

30000

40000

50000

60000

Δ12 Δ14 Δ16

ESI‐MS Spectrum of Pyruvic

Acid Experiment(t=202 min): Regular Distribution of Oligomer

System


Δ12 Δ14 Δ16

Lim mechanism is incomplete; oxalic acid and larger MWt

(oligomers) formAltieri et al., 2006

Unit Name



(OH)2CHCOOH CH3COOH

(glyoxylic acid - hydrated) (acetic acid)



Oligomers


Oxalic acid and oligomers

form. Both are likely to contribute to SOA after droplet evaporation.

Unit Name


Glyoxal:

Lim model reproduces H2

O2

in reaction vessel but poor prediction of oxalic acid (r2

= 0.001) meas. glyoxylic

acid cannot explain oxalic acid formation

0123456789

10

0 50 100 150

Time (min)

Con

cent

ratio

n (m

M)

[H2O2] (3/15/05)[H2O2] (5/7/05)[H2O2] (model)

Hydrogen Peroxide Hydroxyl Radical

[H2 O2 ]


LIM MODEL: Glyoxal Glyoxylic Acid Oxalic Acid

Unit Name


0 200 400 600 8000

10000

20000

30000

40000

50000

m/z0 200 400 600 800

Ion

abun

danc

e

0

20000

40000

60000

80000

100000

120000

117

131

89

73

positive mode

negative mode

Glyoxal

Results ‐

ESI‐MS:

Mixture standard

containing the precursor

and products that are

predicted by initial model

The spectrum we would

expect if the initial

mechanism were complete

m/z

Positive mode

Negative mode

Glyoxal

Oxalic Acid

Ion

Abun

danc

e


Unit Name

Optional Presentation Title Positive mode

0 200 400 600 8000

10000

50000

55000

60000

Negative mode

0 200 400 600 8000

10000

20000

30000

40000

9 min.

149

0 200 400 600 800

Ion

abun

danc

e0

1000030000400005000060000

0 200 400 600 8000

10000

20000

30000

40000

32 min.

173

89

m/z0 200 400 600 800

0100002000030000400005000060000

m/z0 200 400 600 800

0

10000

20000

30000

40000

151 min

89

201313

0 200 400 600 8000

20000

40000

60000

80000

100000

0 200 400 600 8000

10000

20000

30000

40000

0 min.

117

131

Glyoxal rapidly destroyed

Spectral “complexity”develops that cannot be explained by initial mechanism

(large compounds with alcohol/aldehyde (pos) and acid (neg) functionalities)

“Complexity” in positive and negative modes dissipates ∼30-40 min

oxalic acid formed (dominates 150 min spectrum)

Glyoxal

Oxalic Acid

Glyoxal

Results: ESI‐MS

Unit Name


-1000

49000

99000

149000

199000

249000

299000

349000

399000

0 2 4 6 8 10 12

Retention Time (min)

Absorbance (mAU)

t = 0 mins. t = 2 mins. t = 32 mins.t = 61 mins.t = 146 mins. Oxalic acid

Unresolved carbon (large, multifunctional, alcohol or acid functionalities)

Formic acid

Glyoxylic acid

Glyoxal Glyoxylic Acid Oxalic Acid


Glyoxal

Results: ESI‐MS

Unit Name


Expanded Glyoxal

Photooxidation

Mechanism


(glyoxal-hydrated) (OH)2CHCH(OH)2

(OH)2CHCOOH (glyoxylic acid-hydrated)

HOOCCOOH (oxalic acid)

CO2

HCOOH(formic acid)

large multifunctional

compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH




CO2

HCOOH(formic acid)


compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH

a

bc

k = 3E10k = 1.1E8

k = 5E3

.OH




CO2

HCOOH(formic acid)


compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH




CO2

HCOOH(formic acid)


compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH

a

bc

k = 3E10k = 1.1E8

k = 5E3

.OH

H2 O2

Unit Name


-1000

49000

99000

149000

199000

249000

299000

349000

399000

0 2 4 6 8 10 12


Absorbance (mAU)

t = 0 mins. t = 2 mins. t = 32 mins.t = 61 mins.t = 146 mins. Oxalic acid

Unresolved carbon (large, multifunctional, alcohol or acid functionalities)

Formic acid

Glyoxylic acid

Glyoxal Glyoxylic Acid Oxalic AcidGlyoxal Formic Acid

• Not identified as an aqueous- phase glyoxal oxidation product in the atmospheric chemistry literature

• Food/Dye Lit: Close proximity of the two carbonyl double bonds enhances reactivity toward nucleophilic attack (Rao and Rao J.Anal.Chem., 2005)

HO COH

COH

OHH H

glyoxal hydrated

OH HO COH

COH

OHH H

2 H CO

OH

formic acid

Unit Name


Expanded Glyoxal

Photooxidation

Mechanism





CO2

HCOOH(formic acid)


compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH




CO2

HCOOH(formic acid)


compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH

a

bc

k = 3E10k = 1.1E8

k = 5E3

.OH




CO2

HCOOH(formic acid)


compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH




CO2

HCOOH(formic acid)


compounds

·OH

·OH

·OH

·OH·OH

·OH

H2O2

·OH

a

bc

k = 3E10k = 1.1E8

k = 5E3

.OH

H2 O2

Unit Name


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 100 200 300 400 500

Time (min)

Con

cent

ratio

n (m

M)

0.00

0.05

0.10

0.15

0.20

0.25Predicted formicFormic Acid, Exp. 1, 2Predicted oxalicOxalic Acid, Exp. 1, 2

Measurements and Predictions Using Expanded Mechanism

Formic Acid (r2 = 0.6)

Oxalic Acid (r2 = 0.8)

Meas/Modeled glyoxylic acid <MDL. Only 1% of oxalic acid from glyoxal →

glyoxylic acid → oxalic acid pathway. Large multifunctional products important to oxalic acid formation and contribute to SOA themselves.

Reaction Vessel Max:0.02 g Oxalic / g Glyoxal (90 min)0.3 g MF cmpd / g Glyoxal (30 min)

Carlton et al., 2007

Unit Name


(a) ESI-MS 69 min. neg mode

(b) ESI FT-ICR MS69 min. neg mode

Peak Location300 350 400 450 500

Peak

Hei

ght

0

20

40

m/z50 100 150 200 250 300 350 400 450 500 550 6001000

Ion

abun

danc

e

0

2000

4000

6000

8000

10000

C14H17O12377.070380

C17H13O11393.044360

C16H19O14435.075940

C13H15O12363.054800

C23H13O20465.177920

C12H13O20476.99925

m/z0 100 200 300

Ion

abun

danc

e

0100000200000300000400000500000

73

87

89

MethylglyoxalResults:

PA

GA•“haystacks” with regular pattern of mass differences; oligomer system

•Like pyruvic acid experiments (MG itself not involved)

•Structure not seen in mixed stds (not artifact)

•No oligomers in controls (·OH involved)

OA

Unit Name


Methylglyoxal:

H3C CO

COH

OHH OH H3C C

OCOH

OHH H3C C

OOH H C

OOH+

methylglyoxal hydratedacetic acid formic acid

-1000

49000

99000

149000

199000

249000

299000

0 2 4 6 8 10 12


Absorbance (mAU)

t = 2 mins.

t = 69 mins.

t = 129 mins.

t = 204 mins.

t = 249 mins.

t = 369 mins.Oxalic

Large multifunctional compounds

Formic

Glyoxylic

Pyruvic

Acetic

Abs

orba

nce


t=2 min

Formic and acetic acid form directlyInsufficient glyoxylic to explain oxalicOligomers involved in oxalicOligomers and oxalic → SOA

Unit Name


Expanded Methylglyoxal

Mechanism

CO2

(Methylglyoxal-hydrated)CH3COCH(OH)2



HCOOH(formic acid)


CH3COOH(acetic acid)

CH2(OH)(formaldehyde-hydrated)

.OH

.OH.OH

.OH

.OH

.OH.OH

.OH

.OH

hυ/∙ΟΗ

large oligomericcompounds

hυ/∙ΟΗ

CO2

(Methylglyoxal-hydrated)CH3COCH(OH)2



HOOCCOOH (oxalic acid) HOOCCOOH (oxalic acid)

HCOOH(formic acid)

HCOOH(formic acid)

CH3COCOOH(pyruvic acid)CH3COCOOH(pyruvic acid)

CH3COOH(acetic acid)CH3COOH(acetic acid)



.OH

.OH.OH

.OH

.OH

.OH.OH

.OH

.OH

hυ/∙ΟΗ

large oligomericcompounds

hυ/∙ΟΗ

Initial ‐

Lim

Expanded ‐

experiments

Oligomers

Unit Name


MG UV/H2O2 t=69 min. neg mode fticrms

OM:OC ratio1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Freq

uenc

y

0

200

400

600

800

1000

methylglyoxalpyruvic acidacetic acid

glyoxylic acid

oxalic acidformic acid

300 – 500 amu500 – 700 amu


Methylglyoxal

Results: OM/OC = 1.0‐2.5 (avg

1.9) for m/z>300

FT-ICR provides exact elemental comp. >300 m/z

OM/OC comparable to cloud water, regional aerosol. Lower than organic acids

Unit Name


0

1

2

3

0 1 2 3 4 5 6 7 80

1

2

3

0

5

10

0

1

2

3

0 1 2 3 4 5 6 7 80

1

2

3

02468

0 1 2 3 4 5 6 7 802468

% y

ield

%

yie

ld

cloud cycles0 1 2 3 4 5 6 7 8

0

5

10

cloud cycles cloud cycles cloud cycles

Cloud parcel model: Isoprene with/without cloud chemistry. Barbara Ervens

Collaboration (see poster)

10NOVOC

x

=10NOVOC

x=125

NOVOC

x=

•

Cloud chemistry yields

~ 0.5 -

5% •

Approximately doubles SOA

Gas phase chemistry + uptake only

With cloud chemistry

50NOVOC

x=


Unit Name


CMAQ runs: Annmarie

Carlton Collaboration (see poster)

With and without in‐cloud SOA formation (using Yields of 4 to 30%)


Surface conc. ofSOA from cloud pr

Non-convective Cloud fraction

Free troposphere:SOA from cloud pr

Cloud-free areas

SOA from cloud processing – Eastern United States

Unit Name


Experimental Findings:

Oxalic acid forms from glyoxal/methylglyoxal in aqueous-phase

Oligomers and other large multifunctional compounds also form

Thus, SOA will form through cloud processing

Large multifunctional compounds (including oligomers) appear to play a role in oxalic acid formation

Experiments used to validate and refine reaction pathways/kinetics

This work demonstrates a linkage between marine, biogenic and anthropogenic precursors of glyoxal, methylglyoxal and pyruvic acid (including isoprene) and in-cloud SOA formation


Unit Name


Future DirectionsUse mass spectroscopic tools to better understand:

The structure and properties of oligomers

Oligomer formation and degradation

Pursue continued methylglyoxal

model improvements:Through improved understanding of oligomers

Through experiments with intermediates

Incorporate this process into atmospheric models:Chemical and Cloud parcel models: kinetics to atmospheric yields and parameterizations

Air quality and climate models: Magnitude and implications


Unit Name


AcknowledgementsPast/present Students, Postdocs CollaboratorsAnnmarie Carlton Sybil SeitzingerKatie Altieri Barbara ErvensYi Tan Jeehuin LeeMark Perri John ReinfelderHo-Jin LimAdam Reff

Support Related Modeling StudiesU.S. EPA – STAR CMAQ poster - CarltonNSF Cloud parcel poster - Ervens

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