HR: 1340h
AN: A33A-0808    [Abstracts]
TI: Biomass-Burning Aerosol Particles in Mexico During the MILAGRO Campaign
AU: * Adachi, K
EM: Kouji.Adachi@asu.edu
AF: Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287-1404, United States
AU: * Adachi, K
EM: Kouji.Adachi@asu.edu
AF: Arizona State University, Department of Chemistry and Biochemistry, Tempe, AZ 85287- 1604, United States
AU: Buseck, P R
EM: pbuseck@asu.edu
AF: Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287-1404, United States
AU: Buseck, P R
EM: pbuseck@asu.edu
AF: Arizona State University, Department of Chemistry and Biochemistry, Tempe, AZ 85287- 1604, United States
AU: Yokelson, R J
EM: bob.yokelson@umontana.edu
AF: University of Montana, Department of Chemistry, Missoula, MT 59812, United States
AB: Biomass burning contributes significantly to global radiative forcing through the emission of huge amounts of gaseous and particulate matter to the atmosphere. However, the uncertainty is large when modeling their effects on radiative forcing. The emissions are highly variable and depend on parameters such as vegetation, climate, and the mix of flaming and smoldering combustion. During the MILAGRO (Megacity Initiative: Local and Global Research Observations) field campaign, which took place during March 2006 in Mexico, we collected smoke samples from 63 biomass fires and adjacent haze throughout south-central Mexico using a Twin Otter aircraft (US Forest Service) and C130 aircraft (NSF/NCAR). We used transmission electron microscopy (TEM) and associated techniques such as electron tomography (ET), energy dispersive X-ray spectroscopy (EDS), and electron energy-loss spectroscopy (EELS) to analyze the morphologies, mixing states, and compositions of the emission products. Biomass-burning aerosol particles with aerodynamic diameters <0.3μm consisted mainly of soot particles, sulfates, nitrates, minerals, and organic matter (OM). Almost all soot particles collected directly from biomass-burning smoke were internally mixed with OM. In contrast, about half the soot particles collected from haze within ~10 km of the biomass fires were internally mixed with OM. Our samples that were collected from biomass plumes at different stages of aging in the ambient environment and characterized by using multiple TEM techniques will help understand the properties of biomass-burning aerosol and its contribution to climate.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0355 Thermosphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting