1. 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 Image courtesy of SRTM Team NASA/JPL/NIMA AGU FALL MEETING 2010: A14A-05, 13 December 1700

2. The Soot Particle-AMS

3. BC and absorption instrumentation

4. Cal Tech ground site (northern Los Angeles, CA). 15 May – 15 June 2010 Field deployment: Cal-NEx Los Angeles

5. Black carbon mass spurious SP-AMS signal?

6. Weekday/weekend and diel patterns 3-9 June weekdays only Entire campaign Local morning traffic peak? mean 1 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)

7. Black carbon coatings: 3-9 June early morning pattern in mixing state/coating

8. Black carbon coatings II: 3-9 June SP-AMS coatings normalized by absorption/SP2 rBC for 150 nm BC core only!

9. SP-AMS focusing and BC “size”? No change in Aeth response How do we interpret coating information?

10. Volatility SP-AMS PMF analysis SP2 coating information

11. 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)

12. 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 MC4 NE/H008136/1

16. PIKA analysis needed V mode was sufficient to resolve carbon clusters