Long-Term Monitoring of Atmospheric Aerosols in the Amazon Basin: Balbina and Santarem - aerosol source identification and apportionment
Maria
Lucia
Antunes, UNESP-Unidade Diferenciada Sorocaba/Iperó, malu@sorocaba.unesp.br
(Presenting)
Paulo
Artaxo, Instituto de Física da USP, artaxo@if.usp.br
Fine and coarse aerosol particles have been measured since 1998 in Santarém (2° 6´ 35´´ S, 54° 42´ 30´´ W) and Balbina (1°53´ 57´´ S, 59° 28´ 42´´ W), two semi-remote sites located in Amazon Basin. Sampling was performed using stacked filter units, with a sampling time from 1 to 5 days. Elemental analysis was performed with Particle Induced X-ray Emission (PIXE) at the University of São Paulo. Data analysis was performed using multivariate statistical techniques.
For wet season aerosol concentration, averaging about 9800 ng/m3 (Santarem) and 6200 ng/m3 (Balbina) for particles < 2microns. Concentrations in these periods are high, well above wet season. The biogenic coarse mode aerosol concentrations are similar for wet and dry seasons. The elemental composition is dominated by organic compounds that accounts for about 70% of the aerosol mass. The major trace element present are K, S, Ca, Si, Fe, Al and Mg with other minor trace elements such as P, Zn, Cl. Backward air mass trajectory analyses indicate that air masses derived from the Atlantic Ocean and then passed reaching Santarem and them Balbina. It explains the Cl concentration in these areas. Factor analysis shows the presence of four major aerosol sources for both sites: natural biogenic aerosol, soil dust, sea salt and biomass burning particles (only at the fine mode aerosol). Phosphorus is present in low concentrations, typically around 5 - 10 ng/m3. The participation on P in the fine mode aerosol mass (P/FPM) are similar in Santarem and Balbina. The phosphorous source profile derived from APCA for the biogenic coarse fraction of Balbina aerosol is similar to Santarem.