Characterizing black carbons and biomass burn particulates: Evidence for oxygenated interfaces on aged biomass burn particulates

COLL 351

Mary K. Gilles, mkgilles@lbl.gov1, Rebecca J. Hopkins, RJhopkins@mail.dstl.gov.uk2, Alexei V. Tivanski, alexei-tivanski@uiowa.edu3, Alexander Laskin, Alexander.Laskin@pnl.gov4, Y. Desyaterik4, and Tolek Tyliszczak5. (1) Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS, 6R2100, Berkeley, CA 94720, (2) Detection Department, Defense Science & Technology Laboratory, DSTL Porton Down, Salisbury, Wilts, SP40JQ, United Kingdom, (3) Department of Chemistry, University of Iowa, 100 Chemistry Bldg, E124-FCB, Iowa City, IA 52242-1294, (4) Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O.Box 999, MSIN K8-88, Richland, WA 99352, (5) Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720
Carbonaceous particles formed by combustion may account for a large fraction of light absorbing aerosols. Understanding and characterizing the diversity of particulate matter produced from fossil fuel and biomass burn combustion is important for modeling radiative properties of the atmosphere. Scanning transmission x-ray spectroscopy with near edge x-ray absorption spectroscopy is used to explore the diversity of bonding, carbon sp2 hybridization, and C/O atomic ratios of light absorbing particulates. These include surrogates for laboratory studies of atmospheric processing, spherical aged biomass burn particulates (tar balls), and particulates from laboratory burns of selected biomass fuels. For the tar balls, examination of the carbonyl intensity as a function of particle size indicates the presence of a thin oxygenated interface layer. Additionally, a striking range in particulate matter produced from biomass fuels was observed. Such studies have the potential to improve our understanding of the composition of organic particles and their environmental processing.
 

The Physical Chemistry of Environmental Interfaces
8:30 AM-12:40 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 225, Oral

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008