Transcript Ambient measurements of black carbon using the new SP

AGU FALL MEETING 2010: A14A-05, 13 December 1700
Ambient measurements of black carbon
using the new SP-AMS in conjunction with
other instruments
Hugh Coe, James Allan, Jonathan Taylor, Michael Flynn, Paul
Williams, Gavin McMeeking, Greg Kok, Darrel Baumgardner, Tim
Onasch, Ed Fortner, John Jayne and Doug Worsnop
Image courtesy of SRTM Team NASA/JPL/NIMA
The Soot Particle-AMS
BC and absorption instrumentation
Field deployment: Cal-NEx Los Angeles
Cal Tech ground site
(northern Los Angeles, CA).
15 May – 15 June 2010
Black carbon mass
spurious SP-AMS signal?
Weekday/weekend and diel patterns
3-9 June weekdays only
1 std deviation
mean
Local morning traffic peak?
Marr and Harley, ES&T, 2002 – CENTRAL VALLEY
heavy-duty
light-duty
Entire campaign
Weekend effect has been observed in LA
before: e.g., Turpin and Huntzicker (1991) ;
Young et al. (1994)
Black carbon coatings: 3-9 June
early morning pattern in mixing state/coating
Black carbon coatings II: 3-9 June
for 150 nm BC core only!
SP-AMS coatings normalized by
absorption/SP2 rBC
SP-AMS focusing and BC “size”?
No change in Aeth response
How do we
interpret
coating
information?
Volatility
SP-AMS PMF analysis
SP2 coating information
Attenuation
0.6
BC
LV-OOA
SV-OOA
BBOA
HOA
SO4
NO3
0.4
0.2
0.0
60
80
100
120
140
160
Denuder Temperature (°C)
180
200
220°C
Conclusions
• BC mass shows clear diel and
weekday/weekend patterns at Cal Tech site
• Some evidence of diel pattern in BC coatings
linked to nitrate
• No clear effect on Aethalometer absorption!
• Volatility of coatings consistent with
expectations
• SP-AMS capable of measuring BC mass and
coatings; quantification a major development
target (calibration & focusing)
• Thanks to:
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Cal Tech for hosting and CARB for infrastructure/logistics support!
Jochen Stutz (UCLA)
Joost DeGouw, Karl Froyd, Tim Bates, Shane Murphy (NOAA)
Jose Jimenez, Patrick Hayes, Amber Ortega (CU Boulder)
John Seinfeld, Puneet Singh (Caltech)
Paola Formenti (Aerodyne)
MC4
Jim Smith (NCAR)
NE/H008136/1
Manuel Dall’Osto (IDAEA-CSIC)
Stefano Decesari (CNR Bologna)
The rest of the Calnex-LA team
Air from stack
PM1 cyclone
Thermal
denuder
Drier
Bypass
Automated Valve
Aethalometer SP-AMS PASS SP2
200
350
Numbers denote mobility diameter in nm
225
Coefficient values ± one standard deviation
a
=-7.153 ± 21.2
b
=181.48 ± 28.1
200
SP-AMS ion rate (Hz)
150
100
500
250
50
80
0
0.0
125
0.2
0.4
0.6
0.8
-3
SP2 mass (µg m )
1.0
1.2
• PIKA analysis
needed
• V mode was
sufficient to
resolve carbon
clusters