Hugh Coe, James Allan, Jonathan Taylor, Michael Flynn, Paul Williams, Gavin McMeeking, Greg Kok, Darrel Baumgardner, Tim Onasch, Ed Fortner, John Jayne.

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

Ambient measurements of black carbon using the new SP-AMS in conjunction with other instruments

Ambient measurements of black carbon using the new SP-AMS in conjunction with other instruments

Image courtesy of SRTM Team NASA/JPL/NIMA

AGU FALL MEETING 2010: A14A-05, 13 December 1700

The Soot Particle-AMS

BC and absorption instrumentation

Cal Tech ground site (northern Los Angeles, CA).

15 May – 15 June 2010

Field deployment: Cal-NEx Los Angeles

Black carbon mass

spurious SP-AMS signal?

Weekday/weekend and diel patterns3-9 June weekdays only

Entire campaign

Local morning traffic peak?

mean1 std deviation

Marr and Harley, ES&T, 2002 – CENTRAL VALLEY

light-duty

heavy-duty

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

SP-AMS coatings normalized by absorption/SP2 rBC

for 150 nm BC core only!

SP-AMS focusing and BC “size”?

No change in Aeth response

How do we interpret coating information?

0.6

0.4

0.2

0.0

Att

en

ua

tion

220°C2001801601401201008060Denuder Temperature (°C)

BC LV-OOA SV-OOA BBOA HOA SO4

NO3

Volatility

SP-AMS PMF analysis SP2 coating information

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:– 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)– Jim Smith (NCAR)– Manuel Dall’Osto (IDAEA-CSIC)– Stefano Decesari (CNR Bologna)– The rest of the Calnex-LA team

MC4NE/H008136/1

Air from stack

SP-AMS

Thermaldenuder

Aethalometer

PM1 cyclone Drier

SP2PASS

Bypass

Automated Valve

Air from stack

SP-AMS

Thermaldenuder

Aethalometer

PM1 cyclone Drier

SP2PASS

Bypass

Automated Valve

200

150

100

50

0

SP

-AM

S io

n ra

te (

Hz)

1.21.00.80.60.40.20.0

SP2 mass (µg m-3

)

350

200

80

500250

125

225

Numbers denote mobility diameter in nm Coefficient values ± one standard deviation

a =-7.153 ± 21.2b =181.48 ± 28.1

• PIKA analysis needed

• V mode was sufficient to resolve carbon clusters

36.1536.1036.0536.0035.9535.9035.85

15

10

5

0

Diff

, Hz

15

10

5

0

Op

en, H

z/n

s15

10

5

0

Clo

sed,

Hz/

ns

1.00.0

-1.0

Res

id

HCl

H234

S

C3