HR: 17:30h
AN: A34B-07    [Abstracts]
TI: Individual Particle Analysis of Biomass Burning Aerosols During the Yosemite Aerosol Characterization Study
AU: * Hand, J L
EM: hand@cira.colostate.edu
AF: Cooperative Institute for Research in the Atmosphere, Colorado State University 1375 Campus Delivery, Fort Collins, CO 80523 United States
AU: Malm, W C
EM: malm@cira.colostate.edu
AF: National Park Service Cooperative Institute for Research in the Atmosphere, Colorado State University 1375 Campus Delivery, Fort Collins, CO 80523 United States
AU: Laskin, A
EM: alexander.laskin@pnl.gov
AF: William R. Reilly Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory P. O. Box 999, MSIN:K8-88, Richland, WA 99352 United States
AU: Day, D
EM: day@cira.colostate.edu
AF: Cooperative Institute for Research in the Atmosphere, Colorado State University 1375 Campus Delivery, Fort Collins, CO 80523 United States
AU: Lee, T
EM: thlee@lamar.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523 United States
AU: Carrillo, J
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523 United States
AU: Collett, J
EM: collett@lamar.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523 United States
AB: The Yosemite Aerosol Characterization Study of summer 2002 occurred during an active fire season in the western U.S., and provided an opportunity to investigate many unresolved issues related to the effects of carbonaceous aerosols on visibility. Single particle analyses were performed over field collected aerosol samples using computer-controlled scanning electron microscopy with energy-dispersed detection of X-rays (CCSEM/EDX). Individual particle mixing characteristics based on composition data and morphology information suggest the major types of particles were organic/inorganic inclusions with volatile coatings, and tar balls. Tar balls were associated with long-range transport of biomass smoke to the park. These particles were associated with high particle light scattering coefficients during the peak of a smoke/haze event, as determined by other aerosol measurements concurrently performed during the study. The correlation between the frequency of the occurrence of tar balls and black carbon concentrations from a dual- wavelength aethalometer (370 and 880 nm), as well as the insignificant amounts of soot particles observed with the SEM, suggest that tar balls are absorbing in the UV and near-IR range of the solar spectrum. These results have important implications for visibility and climate considerations because absorption of solar radiation from biomass burning aerosols is typically assumed to be due to elemental carbon only.
DE: 0305 Aerosols and particles (0345, 4801)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting