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Measurements of Fine Aerosol Inorganic Composition
Chris Hennigan, Scott Sandholm, Rodney WeberMarch 2005
Method: PILS-IC
Drains Debubbler
Transport Liq. Flow(LiF) aq.
Drain Drain
Anion Cation
Drain
IonChromatographs
Vac. Pump
Denuders(Gas Removal)
Multi-channel activatedCarbon (MAST)
Na2CO
3 & H
3PO
4
Particle SizeSelector
(PM1)
water
Na2CO3, Citric Acid
14.5 L/min sampling rate
Species Measured (Detection Limit µg/m3):Na+ (0.2), NH4
+ (0.2), K+ (0.5), Ca2+ (0.2), Mg2+ (0.1)Cl- (0.02), SO4
2- (0.03), NO3- (0.04)
Sample Rate: 2.4 minutes
Fine Particle (PM1.0) INTEX-NA Concentrations
Mean Standard Dev. Min (LOD/2) MaxNa+ 0.11 0.15 0.10 4.35NH4
+ 0.92 1.33 0.10 8.28Ca2+ 0.11 0.14 0.10 4.15K+ 0.25 0.18 0.25 7.66Mg2+ 0.05 0.05 0.05 1.90Cl- 0.02 0.11 0.01 4.34NO3
- 0.09 0.26 0.02 2.90SO4
2- 1.38 2.39 0.02 19.35
All Data: µg/m3 at 20°C 1 atm
• Na+, Ca2+, K+, Mg2+, Cl- all near/below LOD throughout mission• SO4
2- dominate ionic component
NO3 Spatial Distribution (DC-8)
7000
6000
5000
4000
3000
2000
1000
Alti
tude
(m)
2.52.01.51.00.50.0Nitrate (ug/m3
)
60
50
40
30
-140 -120 -100 -80 -60 -40
2.52.01.51.00.5
Nitrate (ug/m3)
SO4= Spatial Distribution (DC-8)
60
50
40
30
-140 -120 -100 -80 -60 -40
151050
Sulfate (ug/m3)
7000
6000
5000
4000
3000
2000
1000
Alti
tude
(m)
151050Sulfate (ug/m3
)
NH4 Spatial Distribution (DC-8)
Ammonium data for 9 of 18 flights
7000
6000
5000
4000
3000
2000
1000
Alti
tude
(m)
86420Ammonium (ug/m3
)
60
50
40
30
-140 -120 -100 -80 -60 -40
8642
Ammonium (ug/m3)
Aerosol apparent acidity: (NH4)2SO4
0.4
0.3
0.2
0.1
0.0
NH
4 (µ
Eq
m-3
)
0.40.30.20.10.0
NO3 + SO4 (µEq m-3)
1
1
fit forced thru 0Slope = 1.16R2 = 0.76
SO4:– dominant ionic species– highest in 0-2 km alt.– High scattering, vol.
7000
6000
5000
4000
3000
2000
1000
Alti
tude
(m)
20151050Sulfate (ug/m3)
10
8
6
4
2
Alti
tude
(km
)
4003002001000450nm submicron scat. (Mm-1)
10
8
6
4
2A
ltitu
de (k
m)
1008060402000.3 - 2 um Volume (um3/cm3)
400
NOAA P3 Results: Similar but Different– SO4
= dominates inorganic – Highest at low altitudes
6
5
4
3
2
1
0
0.01 0.1 1 10 100
WSOC/Sulfate, µgC/µgSO 4=
6
5
4
3
2
1
0
3020100
Sulfate, µg m-3
6
5
4
3
2
1
0
2520151050
WSOC, µgC m-3
NOAA P3: ITCT 2K4
NOAA P3 Results: Similar but Different– Not as neutralized
NASA DC-8 NOAA P3
0.4
0.3
0.2
0.1
0.0
NH
4 (µ
Eq
m-3
)
0.40.30.20.10.0
NO3 + SO4 (µEq m-3)
1
1
fit forced thru 0Slope = 1.16R2 = 0.76
0.6
0.5
0.4
0.3
0.2
0.1
0.0
NH
4 (µ
Eq
m-3
)
0.60.50.40.30.20.10.0
NO3 + SO4 (µEq m -3)
Fit Forced thru 0slope = 0.66R2 = 0.75
NOAA P3: More Detailed Studies of Specific Plumes
37
36
35
34
33
32
-88 -86 -84 -82 -80
100
80
60
40
20
0
SO
2 sources
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
NH
4/SO
4 molar
5:00 PM8/15/04
6:00 PM 7:00 PM 8:00 PM
5000
4000
3000
2000
1000
0
Altitude (m
)
14
12
10
8
6
4
2
0
SO
2 (p
pb)
15
10
5
0
Sul
fate
(ug/
m3 )
alt SO4 SO2 NH4_SO4_ratio
X•
0.4
0.3
0.2
0.1
Con
cent
ratio
n, E
qu/m
3
3:30 PM7/20/04
4:00 PM 4:30 PM
6000
5000
4000
3000
2000
1000
Altitude, m
NH4
SO4
Alt.
Weber et al. JAWMA 2003
Fine Particle SO4= Source ?
A Near-BL Analysis (z < 2.2 km)
• Analyze legs below 2.2 km alt.
• Each BL pass = 1 data point
• Minimum 3 SO4=
measurements per pass, ~ constant altitude
• Total of 79 BL passes analyzed (5 excluded)
7000
6000
5000
4000
3000
2000
1000A
ltitu
de (m
)
20151050Sulfate (ug/m3)
2.2 km
1999 SO2 Emissions (tons/yr)
50
45
40
35
30
25
-120 -110 -100 -90 -80 -70
200
150
100
50
0
x103
Source: EPA National Emissions Inventory 1999, courtesy of NOAA
**Only point sources with > 500 tons/yr SO2 emissions plotted
Ohio River Valley23% of all SO2 emissions
NOAA HYSPLIT3-5 day back trajectory for each DC-8 BL pass
60
50
40
30
-120 -100 -80 -60 -40
flight pass back trajectory
Back Trajectories Analysis for DC-8 Legs, Alt. < 2.3 km
60 Non-ORV79 BL passes analyzed(67 are East of Miss. R.) 19 ORV, 25%
60
50
40
30
-120 -100 -80 -60 -40
Non-ORV pass ORV pass
ORV vs. Non-ORV results
0
1
2
3
4
5
6
ORV Non-ORV
Avg. SO4
=
(µg/m3)
Avg. Total SSO4
= + SO2(µgS/m3)
AverageSO
4=/(SO
4=+SO
2)
(molar ratio)
5.58
1.67
4.69
2.08
0.40.11
Distribution of sulfate concentration below 2.2 km
1.0
0.8
0.6
0.4
0.2
0.0Frac
tion
of P
asse
s w
/ Hig
her S
O4
14121086420Average SO4 (ug/m3)
ORV
Non-ORV
ORV Non-ORV
Altitude vs. SO4: Ohio RV vs. Non-Ohio RV
7000
6000
5000
4000
3000
2000
1000
Alti
tude
(m)
20151050Sulfate (ug/m3
)
Non-ORV ORV
A Unique Compound Observed During Azores Intercomparison Flight 7/28/04
Unknown Compound• Comes out at phosphate• Not MS
1.5
1.0
0.5
Con
cent
ratio
n (u
g/m
3 )
4:15 PM7/28/04
4:30 PM 4:45 PM 5:00 PM 5:15 PM
7000
6000
5000
4000
3000
2000
1000
Altitude (m
)
PILS sulfate PILS unknown altitude
SO4=: AMS significantly higher than PILS; generally not observed
Unknown Compound Correlates with "Fine"-Particle Volume and DMS
1.5
1.0
0.5
Ion
conc
entra
tion
(ug/
m3 )
4:15 PM7/28/04
4:30 PM 4:45 PM 5:00 PM 5:15 PM
7
6
5
4
3
2
1
0
0.2 - 3 um V
olume (um
3/cm3)
PILS sulfate PILS unknown 0.3 - 2 um Volume
1.5
1.0
0.5
Ion
conc
entra
tion
(ug/
m3 )
4:15 PM7/28/04
4:30 PM 4:45 PM 5:00 PM 5:15 PM
25
20
15
10
5
DM
S (pptv)
PILS sulfate PILS unknown DMS
Summary
• Sulfate: dominant fine inorganic aerosol species measured in summer 2004 INTEX-NA (and NEAQS-ITCT 2004) study– Highest at low altitudes – DC-8 most often (NH4)2SO4 (neutralized), not observed on
NOAA P3
• Air masses that passed through the Ohio River region contained, on average, 3 times as much SO4
= (twice as much total S) as those that did not, (observed widely east of Miss. R.).
• Unidentified "fine particle" constituent observed in marine BL– Concentrations could be higher than SO4
2-.– May be some marine sulfur compound.
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