HR: 0800h
AN: A41D-0735    [Abstracts]
TI: Size-Segregated Aerosols in the Brazilian Amazon: Chemical Composition using ICP-OES, IC, LTM and Thermal-Optical Analyses
AU: * Soto-García, L
EM: lydializ_23@yahoo.com
AF: Institute for Tropical Ecosystem Studies (ITES), University of Puerto Rico PO Box 21910, San Juan, 00931-1910, Puerto Rico
AU: * Soto-García, L
EM: lydializ_23@yahoo.com
AF: Department of Chemistry University of Puerto Rico, PO Box 23346, San Juan, 00931-3346,
AU: Mayol-Bracero, O L
EM: omayol@adam.uprr.pr
AF: Institute for Tropical Ecosystem Studies (ITES), University of Puerto Rico PO Box 21910, San Juan, 00931-1910, Puerto Rico
AU: Mayol-Bracero, O L
EM: omayol@adam.uprr.pr
AF: Department of Chemistry University of Puerto Rico, PO Box 23346, San Juan, 00931-3346,
AU: Andreae, M O
EM: andreae@mpch-mainz.mpg.de
AF: Biogeochemistry Department Max Planck Institute for Chemistry, P.O. Box 3060, Mainz, D-55020, Germany
AU: Wofgang, E
EM: elbert@mpch-mainz.mpg.de
AF: Biogeochemistry Department Max Planck Institute for Chemistry, P.O. Box 3060, Mainz, D-55020, Germany
AU: Voss, H
EM: elbert@mpch-mainz.mpg.de
AF: Biogeochemistry Department Max Planck Institute for Chemistry, P.O. Box 3060, Mainz, D-55020, Germany
AU: Artaxo, P
EM: artaxo@if.usp.br
AF: Institute for Physics, University of São Paulo, Rua do Matao, Travessa R, 187, Sao Paulo, 05508-900, Brazil
AU: Maenhaut, W
EM: Willy.Maenhaut@UGent.be
AF: Department of Analytical Chemistry Institute for Nuclear Sciences, Proeftuinstraat 86, Gent, B-9000, Belgium
AU: Kirchstetter, T
EM: twkirchstetter@lbl.gov
AF: Atmospheric Sciences Department Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS70-108B, Berkeley, CA 94720, United States
AU: Novakov, T
EM: tnovakov@lbl.gov
AF: Atmospheric Sciences Department Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS70-108B, Berkeley, CA 94720, United States
AB: Aerosols from biomass burning increase the number of cloud condensation nuclei, reducing cloud droplet size and, therefore, modifying rainfall location and intensity. The size-resolved chemical composition of these aerosols is important to understand these processes. As part of the (Large Scale Biosphere Atmosphere Experiment in Amazonia - Smoke Aerosols, Clouds, Rainfall and Climate: Aerosols from Biomass Burning Perturb Global and Regional Climate) (LBA-SMOCC) we collected aerosol samples at a pasture site in the Amazon Basin. The sampling period (September to November 2002) included the end of the dry season, the transition period, and the beginning of the wet season. A 13-stage Dekati low-pressure impactor was used to collect particles with D_p between 0.03 μm and 10 μm. Gravimetric analyses were performed to determine the total aerosol mass concentrations. Inductively coupled plasma with optical emission spectroscopy (ICP-OES) was used for the determination of the mass concentrations of Al, B, Ca, Fe, K, Mg, Mn, Na, Si, and Zn. Ion chromatography (IC) was used for the following water-soluble ions Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, Cl^-, NO₃^-, and SO₄^2-. For the analysis of the carbonaceous fraction we used a light transmission method together with thermal-optical analyses. Preliminary results showed that the mass concentrations of the fine fraction (D_p <1 μm) during the whole period ranged from 5.1 to 144.2 μg m^-3. The inorganic fraction concentrations determined by the ICP-OES showed values between 0.1 and 11.8 μg m^-3. The highest concentrations for the total mass and the inorganic fraction were observed during the dry season due to proximity of the fires to the sampling location. The most abundant elements measured by the ICP-OES were Si, K, and Al during the dry season and Si during the beginning of the wet period. The inorganic fraction, as determined from the ICP-OES, represents 5%, 8%, and 18% of the total mass for the dry, transition, and wet periods, respectively, showing that the inorganic fraction is more significant for the wet season. Further, we present a complete set of the ICP-OES results for the three periods together with the IC results and we discuss the contribution of the carbonaceous fraction.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting