characterization of particulate organic nitrates and sulfates...

Characterization of particulate organic nitrates and sulfates based on high resolution

aerosol mass spectrometry in urban atmosphere, Seoul.

Hwajin Kim, Qi Zhang, Sunhye Kim, Jisoo Park, Jungeun Lee, Yejin LeeKorea Institute of Science and Technology

2019-8-25

8/25/2019, AMS user’s meeting, Lund University

• PM Concentration during summer is the lowest among four different seasons.• In terms of PM2.5, it sometimes could be problematic.• Intensive SOA formation occur during summer. • Less impact of transport, thus important to investigate the other impacts.• A lot of interesting aerosol chemistries occur due to different

meteorological condition(strong solar radiation, high RH etc.)

Seasonal variations of PM in Seoul, Korea

[Provided by EPA‐Korea]

However,

Spring Summer Fall Winter[Include yellow sand conc.]

Aerosol Characteristics and Sources in Seoul, Korea

Sampling SiteNational Ambient Monitoring SiteNational Meteorology Monitoring Site

Bukhansan national Park

chinaKorea

Japan

SeoulGyeonggi

Do

Han River

Incheon

(a)

(b)

(c)

(d)

Summer : 2016 July 27‐ Aug.31

KIST HR-ToF-AMS : Real time measurement of Non-Refractory PM1 composition and Chemistry

Instrumentation

Measured Species

HR-ToF-AMS

Quantitative composition of PM1 (organic, nitrate, sulfate, ammonium and chloride)

Size resolved Chemical composition of PM1

Elemental composition (O/C, H/C, OM/OC)

OA Source apportionment by PMF, later.

SMPSParticle size dist. and conc. (19‐948 nm)

MAAP(670nm)

Concentration of BC(+ 7wl aethaolometer)

PAXScattering, absorption and extinction

coefficientVOCUS-PTR-MS

VOC, oxidized precursors (from 2019.10~)

HR‐ToF‐AMS

SMPSPM2.5impactor MAAP

PAX

Period Winter Spring (KORUS‐AQ) Summer

RH(%) (Avg± 59 % ±12 62 %± 22 66 %± 14

Temp. (°C) (Avg± ‐0.24°C± 3.1 19 °C±5.0 28 °C±4.1

Ave PM1 loading (µg/m3)

27.5 µg/m3 22.1 µg/m3 20.2 µg/m3

WS (m/s) 1.4 1.7 2.1

Organic sources SVOOA, LVOOA, HOA, BBOA, COA

SVOOA, LVOOA, COA, HOA

LOOOA, MOOOA,NOA, OOA, COA, HOA, NO3‐

OA, SO4‐OA

Overall characteristics of PM2.5 in Seoul

051015202530

5 10 15 20 25 30

0

45

90

135

180

225

270

315

0 - 0.6 0.6 - 1.2 1.2 - 1.8 1.8 - 2.4 2.4 - 3 3+

WS (m/s)

0

10

20

30

40

10 20 30 40

0

45

90

135

180

225

270

315

0 - 0.6 0.6 - 1.2 1.2 - 1.8 1.8 - 2.4 2.4 - 3 3+

Wind Speed (m/s)

*Winter: Dec. 5,2015 –Jan.22, 2016/ Spring: April 14‐June 15, 2016/ Summer: July 27‐Aug 31 2016

051015202530

5 10 15 20 25 30

0

45

90

135

180

225

270

315

0 - 0.6 0.6 - 1.2 1.2 - 1.8 1.8 - 2.4 2.4 - 3 3+

[Kim et al., ACP, 2017; Kim et al., ACP, 2018; Kim et al., Chemosphere, 2019]]

Overall characteristics during summer

40

30

20

10

0Org

anic

mas

s (µ

g/m

3 )

80

60

40

20

0

PM1

(µg/

m3 )

7/29 8/1 8/4 8/7 8/10 8/13 8/16 8/19 8/22 8/25 8/28 8/31

Date&Time(KST)

100

80

60

40

20

0

% o

f PM

1

25

20

15

10

5

0

Inorganic & BC m

ass(µg/m

3)

80

60

40

20

0

SMPS Volum

e (µm

3/cm3)

Cl-

BC

NH4+

Org NO3 SO4

PM1 = Org + SO42- + NO3

+ + Cl- + BC SMPS volume Daily AvgPM1

Org NO3+ SO4

2-

NH4+ Cl- BC

• There’s no significant haze episodes but ranges in composition changes are considerable

44%

17%

20% 12%

7%

Overall characteristics during summer

50%

7%

27% 9%

7%

14

12

10

8

6

4

2

0

NH

4+ pre

dict

ed (µ

g/m

3 )=S

O4 x

2 x

18/

96 +

NO

3 x 1

8/62

+ C

l x 1

8/35

.5

1086420 NH4

+ measured (µg/m3)

r2 = 0.99Slope = 1.355 ± 0.001

7/21/20167/31/20168/10/20168/20/20168/30/2016

Date

• Sulfate & organic fractions are higher and nitrate fraction is lower

• Summer PM is somewhat acidic whereas winter PM is well neutralized.

• Possible to have less ammonium due to high temperature

• Possibility to have organic combined sulfate and nitrate

Avg PM1= 20.2 µg/m3

Avg PM1= 27.5 µg/m3

Summer

Winter

AMS

NH

+m

easu

red

(µg/

m3 )

OA Source during summer: Org+Inorg combined

20

0100908070605040302010

m/z (amu)

20

0

10

0

10

0

10

0

10

0

10

0

840

Factor 1O/C = 0.78, H/C = 1.61, N/C = 0.044, OM/OC = 2.22








% o

f tot

al

CxHy CxHyO1 CxHyO2 HyO1CxHyNpCxHyOzNp SOx NOx NHx Cl

• 8 organic factors were observed. (vs 5 factors during winter)• Two of them are primarily composed of ammonium sulfate and ammonium nitrate• Rest are probably combined with organic

20100

Mas

s C

onc.

(µg/

m3 )

7/29 8/4 8/10 8/16 8/22 8/28Date and time (KST)

10

0

840

2.01.00.0

5

0

6

0

5

0

840

6420Fa

ctor

7(H

OA)

7/31 8/5 8/10 8/15 8/20 8/25 8/30Date and Time (KST)

6420

Factor5(H

OA)

302520151050Fact

or1

(NO

3)

12840

Fact

or2

(SO

4)

86420

Fact

or6

(LVO

OA)

6420

Fact

or5

(CO

A)

86420

Fact

or8

(OO

A)

86420Fa

ctor

3(S

VOO

A)

2.52.01.51.00.50.0Fa

ctor

4(N

OA)

1086420

Factor3

6420

Factor4(C

OA)

543210

Factor6(O

OA)

43210

Factor1

6420

Factor2(SVO

OA)

543210

Factor6(O

OA)

1086420

Factor3

Inorg combined factors Org only factors

Org + InorgCombined

Org only

20100

100908070605040302010m/z (amu)

3020100

1050

86420

86420

1050

1086420

86420









% o

f tot

al


151050

100908070605040302010m/z (amu)

1050

1050

1086420

1050

1086420







% o

f tot

al

CxHy CxHyO1 CxHyO2 HyO1CxHyNpCxHyOzNp

8factor

OA Source during summer: Org+Inorg combined

OA Source apportionment in Seoul Korea during summer: org+inorg combined

20

0100908070605040302010

m/z (amu)

20

0

10

0

10

0

10

0

10

0

10

0

840









% o

f tot

al


‐ ~77 % of sulfate and ~80 % of nitrate are in inorganic phase

‐ Others may exist as organic combined

1.0

0.8

0.6

0.4

0.2

Mas

s Fr

actio

n

CHCHO1

CHO2 HOCHN

CHONCHOS

Sulfate

Nitrate

LOOOA HOA MOOOA COA NOA OPOA SO4-OA NO3-OA

10

8

6

4

2

0

NH

4+ pre

dict

ed (µ

g/m

3 )

1086420

NH4+ measured (µg/m3

)

r2 = 0.862Slope = 1.057 ± 0.003

Estimation of Particulate Organic nitrateComparisons between two methods

1.0

0.8

0.6

0.4

0.2

0.0Org

anic

NO

3 PM

F (µ

g/m

3 )

7/27 7/31 8/4 8/8 8/12 8/16 8/20 8/24 8/28Date and Time (KST)

0.8

0.6

0.4

0.2

0.0

Organic N

O3 ratio (µg/m

3)

OrgNO3_PMF OrgNO3_ratio

0.8

0.6

0.4

0.2

0.0

Org

anic

NO

3 ra

tio (µ

g/m

3 )

1.00.80.60.40.20.0Organic NO3 PMF (µg/m3)

r2 = 0.696Slope = 0.691 ± 0.005

7/31/2016

8/10/2016

8/20/2016

8/30/2016

12% 88%

SMA(Aug.)PMF

Fraction of organic nitrates (by mass) in ambient OA (assume MW = 200 ‐300 g/mole, Rollins et al.,2012)

8% 92%

SMA(Aug.)ratio

1.2

1.0

0.8

0.6

0.4

0.2

0.0

Con

c. (µ

g/m

3 )

PMF Ratio

NO3org NO3Inorg

0.27(23%)0.16-0.2(13-17%)

Good Correlation between organic nitrates and SOA factors

1.2

1.0

0.8

0.6

0.4

0.2

0.0

Org

_NO

3_PM

F (µ

g/m

3 )

1086420LOOOA (µg/m3)

r = 0.891Slope = 0.114 ± 0.001

7/31/2016

8/10/2016

8/20/2016

8/30/2016

1.0

0.8

0.6

0.4

0.2

0.0

Org

_NO

3_PM

F (µ

g/m

3 )

1086420MOOOA (µg/m3)

r = 0.930Slope = 0.1 ± 0

7/31/2016

8/10/2016

8/20/2016

8/30/2016

1.0

0.8

0.6

0.4

0.2

0.0O

rg_N

O3_

PMF

(µg/

m3 )

302520151050OOA (µg/m3)

r = 0.985Slope = 0.033 ± 0

7/31/2016

8/10/2016

8/20/2016

8/30/2016

1.2

1.0

0.8

0.6

0.4

0.2

0.0

Org

_NO

3_PM

F (µ

g/m

3 )

2.52.01.51.00.50.0NOA (µg/m3)

r = 0.886Slope = 0.424 ± 0.002

7/31/2016

8/10/2016

8/20/2016

8/30/2016

0.8

0.6

0.4

0.2

0.0

Org

_NO

3_ra

tio (µ

g/m

3 )

1086420LOOOA (µg/m3)

r = 0.721Slope = 0.079 ± 0.001

7/31/2016

8/10/2016

8/20/2016

8/30/2016

0.8

0.6

0.4

0.2

0.0

Org

_NO

3_ra

tio (µ

g/m

3 )

1086420MOOOA (µg/m3)

r = 0.700Slope = 0.066 ± 0.001

7/31/2016

8/10/2016

8/20/2016

8/30/2016

0.8

0.6

0.4

0.2

0.0O

rg_N

O3_

ratio

(µg/

m3 )

302520151050OOA (µg/m3)

r = 0.842Slope = 0.024 ± 0

7/31/2016

8/10/2016

8/20/2016

8/30/2016

0.8

0.6

0.4

0.2

0.0

Org

_NO

3_ra

tio (µ

g/m

3 )

2.52.01.51.00.50.0NOA (µg/m3)

r = 0.795Slope = 0.301 ± 0.003

7/31/2016

8/10/2016

8/20/2016

8/30/2016

• Organic nitrate formation might be related with secondary formation • This is urban, thus, Anthropogenic VOC could paly significant roles in

particulate organic nitrate Anthropogenic VOC + NO3 studies are needed.

Estimation of Particulate Organic Sulfate

Much more complex..& several methods to estimate particulate organic Sulfate 1. PMF method: include SO+, SO2

+ , SO3+, HSO3

+, H2SO4+ in PMF analysis

2. Offline method : FT‐IR , LC‐ESI‐MS/MS to measure the C‐O‐S functional group or organosulfur compounds limited by the availability of authentic standards.(Stone et al., 2012; Maria et al., 2003)

3.Online particle ablation by laser mass spectrometry (PALMS) single particle MSbut quantification issues (Liao et al., 2015;Froyd et al., 2010)

4.AMS Sulfate apportionment method (Chen et al., 2019)

0.25

0.20

0.15

0.10

0.05

0.00

Nor

mal

ized

spe

ctra

10080604020m/z

H2SO4+HSO3

+

SO3+SO2

+

SO+

S+

Estimation of Particulate Organic Sulfate

Only from AS and MSA

Only from AS

70x10-3

60

5040302010

0

f H2S

O4

0.150.100.050.00fHSO3

AMS AS MSA OS

(Chen et al., 2019)

5

4

3

2

1

0

Con

c. (µ

g/m

3 )

PMF

SO4org SO4Inorg

1.29 (23.6%)

• ~18% of sulfate are organic sulfateMore validations are needed

• Aerosol composition, size distribution, sources, and evolutionprocesses were investigated using an HR-ToF-AMS.

• Found the evidence of organic combined SO4 and NO3.

• 13-23% of nitrate and 8-12% of organic are composed of organicnitrate.

• Significant of organic sulfate (18-23% of sulfate) was formed duringsummer, as well.

• Secondary aerosol formations are related with the formation oforganic sulfate and nitrate

• Although mass conc. is lower, summer PM should be characterized.

Summary

characterization of particulate organic nitrates and sulfates...

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