characterization of particulate organic nitrates and sulfates...
TRANSCRIPT
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
Factor 2O/C = 0.78, H/C = 1.77, N/C = 0.036, OM/OC = 2.23
Factor 3O/C = 0.62, H/C = 1.67, N/C = 0.007, OM/OC = 1.98
Factor 4O/C = 0.29, H/C = 2.02, N/C = 0.111, OM/OC = 1.69
Factor 5O/C = 0.19, H/C = 1.85, N/C = 0.004, OM/OC = 1.41
Factor 6O/C = 0.93, H/C = 1.40, N/C = 0.018, OM/OC = 2.38
Factor 7O/C = 0.06, H/C = 2.01, N/C = 0.003, OM/OC = 1.25
Factor 8O/C = 0.29, H/C = 1.63, N/C = 0.001, OM/OC = 1.52
% 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
Factor 1O/C = 0.60, H/C = 1.71, N/C = 0.027, OM/OC = 1.97
Factor 2O/C = 0.76, H/C = 1.76, N/C = 0.032, OM/OC = 2.19
Factor 3O/C = 0.64, H/C = 1.67, N/C = 0.008, OM/OC = 2.00
Factor 4O/C = 0.33, H/C = 1.98, N/C = 0.093, OM/OC = 1.71
Factor 5O/C = 0.21, H/C = 1.84, N/C = 0.003, OM/OC = 1.44
Factor 6O/C = 0.88, H/C = 1.44, N/C = 0.021, OM/OC = 2.32
Factor 7O/C = 0.06, H/C = 2.00, N/C = 0.003, OM/OC = 1.25
Factor 8O/C = 0.29, H/C = 1.65, N/C = 0.001, OM/OC = 1.52
% o
f tot
al
CxHy CxHyO1 CxHyO2 HyO1CxHyNpCxHyOzNp SOx NOx NHx Cl
151050
100908070605040302010m/z (amu)
1050
1050
1086420
1050
1086420
Factor 1O/C = 0.79, H/C = 1.71, N/C = 0.054, OM/OC = 2.26
Factor 2O/C = 0.62, H/C = 1.69, N/C = 0.011, OM/OC = 1.98
Factor 3O/C = 0.79, H/C = 1.56, N/C = 0.030, OM/OC = 2.22
Factor 4O/C = 0.17, H/C = 1.83, N/C = 0.013, OM/OC = 1.39
Factor 5O/C = 0.04, H/C = 2.03, N/C = 0.012, OM/OC = 1.24
Factor 6O/C = 0.28, H/C = 1.58, N/C = 0.005, OM/OC = 1.51
% 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
Factor 1O/C = 0.78, H/C = 1.61, N/C = 0.044, OM/OC = 2.22
Factor 2O/C = 0.78, H/C = 1.77, N/C = 0.036, OM/OC = 2.23
Factor 3O/C = 0.62, H/C = 1.67, N/C = 0.007, OM/OC = 1.98
Factor 4O/C = 0.29, H/C = 2.02, N/C = 0.111, OM/OC = 1.69
Factor 5O/C = 0.19, H/C = 1.85, N/C = 0.004, OM/OC = 1.41
Factor 6O/C = 0.93, H/C = 1.40, N/C = 0.018, OM/OC = 2.38
Factor 7O/C = 0.06, H/C = 2.01, N/C = 0.003, OM/OC = 1.25
Factor 8O/C = 0.29, H/C = 1.63, N/C = 0.001, OM/OC = 1.52
% o
f tot
al
CxHy CxHyO1 CxHyO2 HyO1CxHyNpCxHyOzNp SOx NOx NHx Cl
‐ ~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