5/10/2017

1

Combining Offline and Online AMS Analysis to Understand Aqueous Processing of Aerosols

Qi Zhang

Department of Environmental Toxicology University of California, Davis

AMS Users’ Meeting in BeijingMay 10, 2017

hvProducts

Chromophores

Org, inorg.

Products

OH, 1O2*, 3C*, HO2

-/O2-

hvGas phase species

VOCs (CxHy, RR’CO, RNH2…)Inorg. (NOx, SO2, NH3 …)Oxidants (OH, 1O2

*, O3…)

PM

Secondary aerosol formation (SO42-, SOA)

DepositionGravitational settling

dd = 10 m

dp > 0.1 m

Cloud Processing of Aerosol

PM

Partition,

Reaction

SulfateNitrateAmmoniumLow volatility org (oxygenated, oligomers ….)

PM dp > 0.4 m

RemovalScavenging

5/10/2017

2

Why Study Aq. Processing of Aerosol? 

• Aq. processes

– Influence aerosol comp, size distribution

– Influence aerosol properties (optical, hygroscopic and microphysical)

– Formation of surface‐active and light‐absorbing organic species can affect cloud properties. 

• SOA formed through aqueous reactions (aqSOA) is poorly understood, although aqSOA is likely different than gasSOA: 

– Different reaction pathways 

different SOA composition

Different hygroscopic and optical properties 

Ambient and Laboratory Studies to Investigate Aq‐Processes and Their Effects on Aerosols 

• Field study of fog chemistry and influence of fog processing on aerosol Chemistry during winter in CA– Examine in‐cloud formation and processing of aqSOA by comparing 

interstitial aerosol and cloud/fog water compositions and their evolution characteristics.

– Compare aerosol composition and properties observed during cloudy/foggy conditions vs. those observed during clear conditions immediately before or after the presence of clouds/fogs to gain insights into how aqueous processing affects aerosol properties. 

• Laboratory study aqSOA formation from phenolic compounds under cloud‐ and fog‐drop conditions– Quantify kinetics and SOA yields

– Characterize SOA reaction products and photochemical evolution

– Ambient Particle Characterization and Photochemistry

5/10/2017

3

5http://givemeamomentblog.blogspot.com/2011/01/tule‐fog.html

Fresno

Study of Fog and Aerosol Chemistry in CA

• Regional nighttime fogs during winter in the Central Valley (CV) of California 

• Rapid surface cooling at night due to radiation loss of heat

• Calm, stable met. conditions, suitable for studying aerosol processing. 

• Near ground process, easy to access

Fog Sampling and Analysis

• Samples were collected with a Caltech Active Strand Cloud water Collector (CASCC)

• Droplets > 3.5 µm  (50% efficiency) were collected• Fog sampled analyzed using HR‐ToF‐AMS, Ion Chromatographs (IC), and TOC analyzer

Fog water

Analysis of solution (IC and TOC)

Ambient Aerosol Sampling• In situ measurements with HR‐ToF‐AMS

5/10/2017

4

FogPre fog Post fog

600

400

200

0

SR

(W

m-2

) 20

10

0

T (

ºC)

100

50

0

RH

(%)

100

75

50

25

0

% o

f N

R-P

M1

4.0

3.0

2.0

1.0

0.0

Pre

c. (mm

hr -1)2

1

0

CO

(ppm

) 40

20

0O

3 (ppb)

40

20

0

NR

-PM

1 (µg m

-3)160

Win

d

100

80

60

40

20

0% o

f to

tal n

on

-vo

latil

e d

isso

lve

d m

att

er

in

fo

g

1/9 1/10 1/11 1/12 1/13 1/14 1/15 1/16Date and Time (PST)

Fog 3Fog 2 Fog 4

HOA COA BBOA OOA NO3

SO4

NH4

Cl

(a)

(b)

(c)

(d)

1086420

m/s

Fog 1

(e) F-OA F-NO3

F-SO4

F-NH4

F-Cl

Observation of Fog & Aerosol in Fresno

• Calm wind condition persisted throughout fog events, as well as during the periods representing immediately before and after fog episodes. 

Influence of Fog Processing on Aerosol Properties

POA = HOA + COA + BBOA

of OOA

Ge et al., Environ. Chem. 2012

of OOA

• All secondary aerosol species increased during fog• Sulfate is formed  efficiently in fog water, increase of nitrate is mainly due to partitioning 

5/10/2017

5

9

6

3

0

9

6

3

0

9

6

3

0

9

6

3

0120110100908070605040302010

m/z (amu)

12

9

6

3

0

O/C = 0.42 H/C = 1.43 N/C = 0.017 OM/OC = 1.70

O/C = 0.33, H/C = 1.56 N/C = 0.021 OM/OC = 1.59

O/C = 0.11, H/C = 1.72 N/C = 0.011 OM/OC = 1.30

O/C = 0.09, H/C = 1.80 N/C = 0.010 OM/OC = 1.29

% o

f to

tal s

ign

al in

eac

h M

S

HOA

COA

BBOA

OOA

(a1)

(a3)

(a4)

(a5)CxHy

+ CxHyO1+ CxHyO2

+

HyO1+ CxHyNp

+ CxHyOzNp+

O/C = 0.42 H/C = 1.40 N/C = 0.064 OM/OC = 1.74

F-OA

(a2)

30

25

20

15

10

5

0

f 44

(%)

151050f43 (%)

(b)

F-OA Averaged F-OA Interstitial OA BBOA OOA HOA COA

2.0

1.8

1.6

1.4

1.2

1.0

H:C

0.60.50.40.30.20.10.0

O:C

m = -2+ketone/ aldehyde

m = 0+alcohol/peroxide

m = -1+carboxylic acid

(c)

• F‐OA is chemically more similar to OOA than to POA components • F‐OA appears to be more enriched of carboxylic acids and organic nitrogen 

compounds than OOA

Kim et al., ES&T, submittedNg et al., ACP, 2010 

Chemical Characteristics of Fog Organics

Post Fog

Pre Fog

Fog

8

6

4

2

0

CO (ppm) O3 & NO2 (ppb)

0.8

0.6

0.4

0.2

0.0

12

8

4

0

T (ºC) RH (%)

100

90

80

240

180

120

60

0

Solar R (W m-2

)

18

16

14

12

10

8

(c) (d) (e)

6

4

2

0

Con

c. (

µg/

m3)

Sulfate Ammonium Nitrate Organic (OOA)

2.01.51.00.50.0

Ra

tio

2.01.51.00.50.0

Pre Fog (Aerosol) During Fog (Fog water) During Fog (Interstitial Aerosol) Post Fog (Aerosol)

(a)

(b)

Fog Water / Interstitial Aerosol Post Fog Aerosol / Pre Fog Aerosol

• Calm wind condition persisted throughout the fog event, as well as during the periods representing immediately before and after fog episodes. 

• Secondary species (Nitrate , Sulfate, OOA) are all enhanced during humid period Aqueous phase reaction influence to the formation of secondary organic and inorganic species. 

• Sulfate is formed  efficiently in fog water, increase of nitrate is mainly due to partitioning • Part of the reduction of aerosol loading after fog may be due to depositional losses. 

Evidence for  aqSOA Formation in Fog

Kim et al., ES&T, submitted

5/10/2017

6

1.2

0.8

0.4

0.0

% o

f to

tal o

rgan

ic s

ign

al

CxHyN+

CxHyN2+

CxHyO1N+

(b) HR-ToF-AMS spectrum of ON ions in fog waterm/z 68

m/z 81

m/z 95

m/z 108 m/z 121m/z 133

12001000

800600400200

0

Rel

ativ

e in

ten

sity

18016014012010080604020

m/z (amu)

C3H4N2

C4H6N2

C5H8N2

C6H10N2

C8H12N2

(c) NIST EI mass spectra of 5 Imidazole compounds

NH

NNHN

NHNN

NNHN

Carbonyl (R‐C=O, glyoxal) + ammonia/amine(aq)  imidazole (De Hann et al., 2009; Galloway et al., 2009; Liggio et al., 2005; Trainic et al., 2011)

• Large emissions of gaseous phenols from biomass burning

• High Henry’s Law constant  partition into aq. phases

• Aqueous phenols are rapidly oxidized by a variety of mechanisms: h, ∙OH, 3C* (triplet excited states of OC)

LigninPhenolic compounds

Investigate AqSOA formation from Phenolic Compounds

Non‐phenolic  carbonyls

3,4-dimethoxyBenzaldehyde(DMB)

OH

Phenol(PhOH)

OH

OCH3

Guaiacol(GUA)

OH

OCH3H3CO

Syringol(SYR)

Vanillin (VAN)

O H

OCH3

OH

OH

OH

Catechol (1,2‐Benzene diol)

∙OH3C*

5/10/2017

7

Experimental SetupPhotoreactor

(simulated  sunlight)

Experimental conditions• Phenolic precursors

• [phenols]initial = 100 µM in H2O

• Oxidant:

1. 100 μM H2O2

2. 5μM 3,4‐DMB (3C*)

Analytical techniques• HR‐ToF‐AMS: SOA bulk comp., O/C, OSC• TOC: total organic carbon in soln.

• Nano‐DESI MS: SOA molecular comp.

• IC: small acids in soln.

• HPLC : phenol conc.

(TOC, IC & HPLC)

(AMS)

(nano‐DESI)

14

1.2

1.0

0.8

0.6

0.4

0.2

O/C

(d) (e)1.2

1.0

0.8

0.6

0.4

0.2

O/C

(f)

-0.7-0.5-0.3-0.10.10.30.5

OS

c

76543210

(g)

76543210Hours of irradiation

(h)

-0.7-0.5-0.3-0.10.10.30.5

OS

c

121086420 2420

(i)

100

80

60

40

20

0

% o

f ph

enol

rem

ain

ing

(a)

SYR + OH SYR + 3C*

(b)

GUA + OH GUA + 3C*

1.2

0.8

0.4

0.0

SO

A m

ass /

Initia

l phenol m

ass

(c)

PhOH + OH PhOH + 3C*

Quick Formation of Highly Oxidized aqSOA

Yu et al., ACP, 2016

OSC = 2O/C – H/C

5/10/2017

8

101

102

103

104

105

106

800750700650600550500450400350300250200150100

Molecular Weight (Da)

SYR + 3C*

Hydroxylated SYR

Dimer

TrimerTetramer

C16H18O6

C24H26O9

C32H34O12

0.80.70.60.50.40.3O/C

C8H10O4

C16H18O7

C8H10O5

Pentamer

101

102

103

104

105

106

800750700650600550500450400350300250200150100

SYR + •OH

Hydroxylated SYR

Dimer

Trimer

Tetramer

C16H18O6

C24H26O9

C32H34O12

C8H10O4

C16H18O7

C8H10O5

Pentamer

• Hundreds of SOA species, generally more oxidized than precursor.  • Oligomers (up to hexamers) and derivatives

Yu et al., ACP, 2014

Molecular Comp. of Phenolic aqSOA at t1/2

OH

H3CO

OCH3

OCH3

OH

OCH3

OH

OH

OH

OCH3

OH

OCH3

OH

OCH3

OH

H3CO OCH3

OH

OH

OH

O

H3CO

OH

OCH3

OH

OHOH

OH

O

H3CO

OH

OCH3

OH

O

OOH

OH OH

OOHO

O

OCH3

OCH3

OH

OH

OCH3

OCH3OH

OH

OH

OH

OCH3

OCH3

OCH3

OH

OH

OH

OCH3

OCH3

OH

OH

OH

OH

O

OH

OCH3

OCH3OH

OH

OCH3

OCH3

OHOH

OH

OH

OH

OHOH

OH

OHOH

OH

OH

O

OHO

O

O

OH

OH

OH

OH

O

O

OH

OH

OH

SYR

GUA

PhOH

Examples of Most Abundant Molecules

Yu et al., ACP, 2014

Oligomers, functionalized monomer and oligomers with carbonyl, carboxyl, and hydroxyl groups, demethoxylated aromatic species, ring opening species

5/10/2017

9

5040302010

0

152 (M+•)93 166 (M

+•)138

(d) Methylparaben (NIST) Ethylparaben (NIST)121

5040302010

0

% o

f to

tal s

ign

al

(c) 4,4'-Dihydroxydiphenyl ether (NIST) 202 (M+•)

109

OH OH

OH

OH

OH

OH

OH

OHOOH

OHO

OH

OO

OH

OO

5040302010

0

21020019018017016015014013012011010090807060

m/z (amu)

(f) Phenol (NIST)94 (M

+•)

66

40302010

0

110 (M+•)

81

(e) Catechol (NIST)

64

Hydroquinone (NIST)

40302010

0

(b) Biphenol-4,4'-diol (NIST) 4-Phenoxyphenol (NIST)

186 (M+•)

157

1.00.80.60.40.20.0

PhOH + 3C*

PhOH + •OH186

121110 202

(a)

NIST spectra

AMS spectrum 

Sun et al., ACP, 2010

Identification of AMS tracer ions for phenolic aqSOA

129630

[Syr

ingo

l], [S

OA

] (m

gC/L

)

6.05.55.04.54.03.53.02.52.01.51.00.50.0Irradiation time (hr)

SO

A s

peci

es (

sign

al in

tens

ity)

1.00

0.90

0.80

0.70

O/C

OH

H3CO

OCH3

OCH3

OH

OCH3 OH

OH

OH

OCH3

OH

OCH3

OH

OCH3

OH

H3CO

OH

OCH3

OH

O

OOH

OH OH

OOHO

O

C16H18O6+

(dimer)

C8H10O4+ (mono-OH)

C16H18O7+

(dimer-OH)

CHO2+

(ring-openingspecies)

A

B organic acids by IC

Formation and Evolution of Phenolic aqSOA

• Similar behaviors for different phenols aq reactions. • Formation of a variety of functionalized aromatic and ring‐opening products with high O/C• Varying importance of oligomerization, functionalization, and fragmentation throughout rxn. 

Modified from Yu et al., ACP, 2014, 2016

5/10/2017

10

60

50

40

30

20

10

0

SO

A m

ass

(µ

g/m

3)

6543210Hours of Irradiation

Total Mass 1st gen. 2nd gen. 3rd gen.

20

15

10

5

0

20X1st gen. O/C=0.89, H/C=1.65, OM/OC=2.33

C16H18O6+ (dimer)

20

15

10

5

0% o

f To

tal S

igna

l 20X2nd gen. O/C=0.92, H/C=1.57, OM/OC=2.36

C9H9O4+(monomer deriv.)

20

15

10

5

0

3102902702502302101901701501301109070503010

m/z (amu)

20X3rd gen. O/C=1.04, H/C=1.59, OM/OC=2.52

32

24

16

8

0

2n

d g

en.

10x10-286420

C9H9O4+

R = 0.990

20

16

12

8

4

0

1st

ge

n.

10x10-286420

C16H18O6+

R = 0.997

OCH3H3CO

OH

+ 3C*

1st generation

2nd generation

3rd generation

HCO2+

Formation and Evolution of SYR aqSOA

Yu et al., in prep.

1.00.80.60.40.20.0

SO

A yie

ld

6.05.55.04.54.03.53.02.52.01.51.00.50.0

Hours of Irradiation

1086420

TO

C (m

gC/L)

1.2

1.0

0.8

0.6

0.4

0.2

0.0

O/C

14

12

10

8

6

4

2

0

SO

A li

q C

on

c. (

mg

/L)

10080604020

0

SY

R (

µM

)

70

60

50

40

30

20

10

0

SO

A m

ass (µ

g/m

3)

SYR SOA

Filter Filter Filter

t1/2

1st gen. factor

2nd gen. factor

3rd gen. factor

Connecting Molecular and Bulk Chemical Info.

SYR + 3C*

P1 P2 P3 P4

9%

54%

37%

71%

28%

1% 99% 1%

1st generation

2nd generation

3rd generation

P2 P3 P4

Yu et al., ACP, 2016

5/10/2017

11

Sun et al., ACP, 2010

Observation of Phenolic aqSOA in Fresno PM

Acknowledgments

Funding

Lu Yu  Yele SunXinlei Ge Hwajin KimWenqing Jiang Jianzhong XuSonya Collier Shan Zhou   

CollaboratorsCort Anastasio (UCD) Jeremy Smith (UCD)

Pierre Herckes (ASU) Youliang Wang (ASU)

Alex Laskin (PNNL) Julia Laskin (PNNL)    

5/10/2017

12

References• Yu, L., Smith, J., Laskin, A., George, K. M., Anastasio, C., Laskin, J., Dillner, A. M., and Zhang,

Q.: Molecular transformations of phenolic soa during photochemical aging in the aqueous

phase: Competition among oligomerization, functionalization, and fragmentation, Atmos.

Chem. Phys., 16, 4511-4527, 10.5194/acp-16-4511-2016, 2016.

• Yu, L., Smith, J., Laskin, A., Anastasio, C., Laskin, J., and Zhang, Q.: Chemical characterization

of soa formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl

and hydroxyl radical, Atmos. Chem. Phys., 14, 13801-13816, 10.5194/acp-14-13801-2014,

2014.

• Sun, Y., Zhang, Q., Anastasio, C., and Sun, J.: Insights into secondary organic aerosol formed via

aqueous-phase reactions of phenolic compounds based on high resolution aerosol mass

spectrometry, Atmos. Chem. Phys., 10, 4809-4822, 10.5194/acp-10-4809-2010, 2010.

• Smith, J., Sio, V., Yu, L., Zhang, Q., and Anastasio, C.: Secondary organic aerosol production

from aqueous reactions of atmospheric phenols with an organic triplet excited state, Environ.

Sci. & Technol., 48, 1049-1057, 10.1021/es4045715, 2014.

• George, K. M., Ruthenburg, T. C., Smith, J., Yu, L., Zhang, Q., Anastasio, C., and Dillner, A. M.:

FT-IR quantification of the carbonyl functional group in aqueous-phase secondary organic

aerosol from phenols, Atmos. Environ., 100, 230-237, 10.1016/j.atmosenv.2014.11.011, 2015.