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.

Black carbon aerosol in emissions from biomass burning

in the laboratory and field

G.R. McMeeking1, J.W. Taylor1, A.P. Sullivan2, M.J. Flynn1, S.K. Akagi3, C.M. Carrico2,

J.L. Collett, Jr.2, E. Fortner4, T.B. Onasch4, S.M. Kreidenweis2, R.J. Yokelson3,

C. Hennigan5, A. Robinson5, and H. Coe1

1University of Manchester, 2Colorado State 3University, University of Montana, 4Aerodyne

Research Inc., 5Carnegie Melon UniversityPhoto credit: Dan Welsh-Bon (NOAA)

AGU 2010: A23C-02

Impacts of black carbon on the atmosphere

LaboratoryFLAME-3US Forest Service Fire Science LabMissoula, MontanaSeptember 2009

AircraftSan Luis Obispo Biomass Burning Experiment

USFS Twin OtterCentral California, USA

November 2009

Dan Welsh-Bon (NOAA)

Bob Yokelson (U. of Montana)

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)

Results from a “typical” laboratory experiment

FIRE DURATION

Results from a “typical” fire flight

Emission factors as a function of…

…fuel type

Emission factor = mass species emittedmass fuel consumed

or combustion conditions?

Desert shrubs = 1.5-2 g kg-1 dry fuelSoutheastern grasses = 0.6-1Pine needles = 0-0.5

BC emission factor by type:

Comparing laboratory and field

Optical properties

“Non-BC absorption” / [OC mass]: 532 nm = 0.31 m2/g780 nm = 0.10 m2/g

Sun et al. (2007)

From: Lack and Cappa, AS&T, 2010

Changes in BC mixing state

Photo: Dan Welsh-Bon (CU/NOAA)

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 m2/g at λ = 780 nm, 7.9 m2/g at λ = 532 nm

• OC mass absorption efficiency: 0.1 m2/g at λ = 780 nm, 0.3 m2/g at λ = 532 nm

• BC becomes rapidly mixed/coated with other material for aircraft and smog chamber

Thanks!FLAME 3 project partners (not all pictured)

SLOBBErs

Supported by:

Strategic Environmental Research and Development Program (SERDP)

UK Royal Society Travel Grant

BC emission factors

Emission factor = mass species emittedmass fuel consumed

“Desert” shrubs

pine needles & “duffs”

Mass of fuel consumed estimated from:CO2, CO, fuel carbon content, and mass consumed

Early results from CMU chamber

Proxies for coating thickness on BC increase with time following lights on!

Comparing different BC measurements