Upload
donavan-lansdell
View
214
Download
0
Tags:
Embed Size (px)
Citation preview
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