Estudo dos aerossóis atmosféricos biogênicos e de queimada

• Autor(a) principal: Ramos, Lucas Cardoso
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/5714
• topic: Aerossol; Black carbon; Propriedades ópticas; EDXRF; XPS; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA; Aerosols; Black carbon; Optical properties; EDXRF; XPS

Atmospheric aerosols are solid or liquid particles that remain suspended in gases for a certain time, are fundamental agents for the dynamics of the Earth's atmosphere. Biomass burning is a source of emissions that causes an increase in the concentration of aerosols and the Black Carbon (BC) component in regions close to the fires. Gravimetry and Optical Reflectance techniques were used, respectively, to determine the mass concentration and concentration of BC in a sample of atmospheric aerosols deposited on poly-tetra-fluoro-ethylene (PTFE) filters supported by polypropylene collected in the Pantanal Region of Mato Grosso do Sul. Grossense within the Pantanal Advanced Research Base between the period of August 25, 2022 and September 14, 2022. The presence and concentration of chemical elements in the sample determined through the technique of X-Ray Fluorescence Spectrometry by Energy Dispersion (EDXRF), while X-Ray Photoelectron Spectroscopy (XPS) provides information about the electronic structure of atoms present on the surface of the sample. To explore the potential of the XPS technique, an analysis of a PTFE filter collected in the Amazon in 2017 was carried out, the presence of C and O in the sample was identified and the concentrations related to these elements were quantified. The interpretation of the high-resolution spectrum referring to the peak of C1s considered three carbon components, the position of the peaks of each component indicates the presence of carbon in the elemental form, and the carbon in the carboxyl and alcohol groups. The characterization of the selected ones identified a maximum value of 83.66 ± 2.50 µg m-3 PM2.5 concentration, the average mass concentration value for the period was 36.62 μg m-3. The concentration of aerosols linked to the number of fires close to the study region was identify, so that the periods with the highest number of fires also recorded a higher concentration of PM2.5. The average BC concentration during the sample collection period was 1.83 µg m-3, the variability in BC concentration values showed a strong correlation with the mass concentration values and in comparison with another study carried out in the same location between the years 2012 – 2013 it was possible to verify a considerable increase in the concentration of aerosols in the Pantanal Mato-Grossense region.