Biomass Burning in the Amazon: Characterization of the Ionic Component of Aerosols Generated from Flaming and Smoldering Rainforest and Savannah

Abstract

Samples (170) of biomass combustion smoke were obtained in Brazilian tropical rainforest and savannah during August-September 1992. Speciation of the ionic fraction of fine (d < 2 µm) and coarse (15 µm > d > 2 µm) mode particles was achieved using ion chromatography, and the data were interpreted according to geographical region, vegetation type, and phase of combustion. The species measured were CH_3COO^-, HCOO^-, CI^-, NO_3^-, SO_4^(2-), C_2O_4^(2-), PO_4^(3-), Na^+, NH_4^+, K^+, Mg^(2+), and Ca^(2+). Mean total ionic contents for the fine mode were 5.6% (Brasilia) and 2.2% (Rondonia) and for the coarse mode were 8.3% (Brasilia) and 13.7% (Rondonia). The fine mode ionic fraction was dominated by potassium, chloride, and sulfate, while calcium and acetate were important in the coarse mode. Highest ionic contributions were always observed during flaming combustion. Sources of aerosols were condensation/coagulation, release of partially combusted plant material, and suspension of soil particles.

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