1. Black carbon aerosol in emissions from biomass burning in the laboratory and field G.R. McMeeking 1, J.W. Taylor 1, A.P. Sullivan 2, M.J. Flynn 1, S.K. Akagi 3, C.M. Carrico 2, J.L. Collett, Jr. 2, E. Fortner 4, T.B. Onasch 4, S.M. Kreidenweis 2, R.J. Yokelson 3, C. Hennigan 5, A. Robinson 5, and H. Coe 1 1 University of Manchester, 2 Colorado State 3 University, University of Montana, 4 Aerodyne Research Inc., 5 Carnegie Melon University Photo credit: Dan Welsh-Bon (NOAA) AGU 2010: A23C-02

2. Impacts of black carbon on the atmosphere

3. Laboratory FLAME-3 US Forest Service Fire Science Lab Missoula, Montana September 2009 Aircraft San Luis Obispo Biomass Burning Experiment USFS Twin Otter Central California, USA November 2009 Dan Welsh-Bon (NOAA) Bob Yokelson (U. of Montana)

4. from Schwarz et al., 2006 Why even more biomass burning BC measurements? BC size distributions No filter artifacts BC mixing state Single particle soot photometer (SP2)

5. Results from a typical laboratory experiment FIRE DURATION

6. Results from a typical fire flight

7. Emission factors as a function of… …fuel type Emission factor = mass species emitted mass fuel consumed or combustion conditions? Desert shrubs = 1.5-2 g kg -1 dry fuel Southeastern grasses = 0.6-1 Pine needles = 0-0.5 BC emission factor by type:

8. Comparing laboratory and field

9. Optical properties Non-BC absorption / [OC mass]: 532 nm = 0.31 m 2 /g 780 nm = 0.10 m 2 /g Sun et al. (2007) From: Lack and Cappa, AS&T, 2010

10. Changes in BC mixing state Photo: Dan Welsh-Bon (CU/NOAA)

11. Conclusions Consistent [BC EF vs MCE] for aircraft and laboratory BC EF range between 0-2 g/kg dry fuel Optical properties depend on BC/TC ratio: abs. eff. and wavelength dependence decreases for higher BC mass fractions BC mass absorption efficiency: 3.6 m 2 /g at λ = 780 nm, 7.9 m 2 /g at λ = 532 nm OC mass absorption efficiency: 0.1 m 2 /g at λ = 780 nm, 0.3 m 2 /g at λ = 532 nm BC becomes rapidly mixed/coated with other material for aircraft and smog chamber

12. Thanks! FLAME 3 project partners (not all pictured) SLOBBErs Supported by: Strategic Environmental Research and Development Program (SERDP) UK Royal Society Travel Grant

14. BC emission factors Emission factor = mass species emitted mass fuel consumed Desert shrubs pine needles & duffs Mass of fuel consumed estimated from: CO2, CO, fuel carbon content, and mass consumed

15. Early results from CMU chamber Proxies for coating thickness on BC increase with time following lights on!

16. Comparing different BC measurements