Absorção da radiação solar por partículas de aerossóis no Pantanal Mato-grossense

Abstract

In this study a characterization of the optical properties of particles of biogenic aerosols, of pollution and of fires was carried out. The objective of this work was to study the absorption of solar radiation by aerosol particles in the Mato Grosso Pantanal. Atmospheric aerosol samples were collected from april 2012 to august 2013 at the Advanced Research Base, located in the Mato Grosso Pantanal, Brazil. The sampling device consisted of fine and coarse particulate (AFG) samplers, separating the fine fraction of the aerosol (dp ˂ 2.5 μm) and the coarse fraction (2.5 - 10 μm). Different approaches were used, including in situ measurements of both the Aethalometer and MAAP equipment. With respect to the calculations performed for the absorption Angstrom exponent in relation to the absorption coefficients were corrected for the effects of multiple scattering and the data worked for the Aetalômetro were used the wavelengths of 470 and 880 nm in which presented minimum of 15 Mm-1and maximum of 30 Mm-1in the days most affected by emissions of burnings in the dry period. In relation to the highest concentrations of fine and coarse black carbon were 1.7 and 0.2 µg.m-3 during the dry and rainy period for the samples measured by the filters. For the MAAP equipment, it presents a higher concentration of black carbon in the fine fashion in the period of the fires on the days of 04 and 09 of September of 2012 and the origin of the trajectories calculated with the program Hysplit can be evaluated in the days of intense peak of the material particulate matter, in which wind from the South with lower humidity will increase the emission of aerosols, an intense peak for the relation between organic carbon / elemental carbon. The mean organic carbon (OC) concentration measured was 1.7 µg.m-3 in the dry period and 1.3 µg.m-3 in the rainy season.