ELEMENTAL COMPOSITION OF AEROSOL-PARTICLES FROM 2 ATMOSPHERIC MONITORING STATIONS IN THE AMAZON BASIN

One key region for the study of processes that are changing the compos ition of the global atmosphere is the Amazon Basin tropical rain fores t. The high rate of deforestation nd biomass burning is emitting large amounts of gases and fine-mode aerosol particles to the global atmosp here. Two background monitoring stations are operating continuously me asuring aerosol composition, at Cuiaba, and Serra do Navio. Fine- and coarse-mode aerosol particles are being collected using stacked filter units. Particle induced X-rav emission (PIXE) was used to measure con centrations of up to 21 elements: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr, and Pb. The elemental composit ion was measured at the new PIXE facility from the University of Sao P aulo, using a dedicated 5SDH tandem Pelletron nuclear accelerator. Abs olute principal factor analysis (APFA) has derived absolute elemental source profiles. At the Serra do Navio sampling site a very clean back ground aerosol is being observed. Biogenic aerosol dominates the fine- mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and FPM. Three components dominate the aerosol composition: soil dust par ticles, the natural biogenic release by the forest, and a marine aeros ol component. At the Cuiaba site, during the dry season, a strong comp onent of biomass burning is observed. An aerosol mass concentration up to 120 mug/m3 WaS measured. APFA showed three components: soil dust ( Al, Ca, Ti, Mn, Fe), biomass burning (soot, FPM, K, Cl) and natural bi ogenic particles (K, S, Ca, Mn, Zn). The fine-mode biogenic component of both sites shows remarkable similarities, although the two sampling sites are 3000 km apart. Several essential plant nutrients like P, K, S. Ca, Ni and others are transported in the atmosphere as a result of biomass burning processes.