Engenharia Ambiental

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http://repositorio.ufes.br/handle/10/17610
Programa de Pós-Graduação em Engenharia Ambiental

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URL do programa: http://www.ambiental.ufes.br/pos-graduacao/PPGEA

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    Chemical Characterization of Particles in Iron-rich Atmosphere of Urban and Industrialized Regions.
    (Universidade Federal do Espírito Santo, 2018-08-30) Galvão, Elson Silva; Lima, Ana Teresa Macas; Stuetz, Richard Michael; Santos, Jane Meri; Albuquerque, Taciana de Almeida; Moreira, Davidson Martins; Andrade, Maria de Fátima; Martins, Jorge Alberto
    Epidemiological studies have shown the association of airborne particulate matter (PM) size and chemical composition with health problemsaffecting the cardiorespiratory and central nervous systems. Therefore, PM source identification is an important step in air quality managementprograms. Receptor models are frequently used for PM source apportionment studies to identify the contribution of local sources. Despite the benefits of using receptormodels for air quality management, limitations such as collinearity effectsin which sources have similar chemical profilesrestrict their application or compromise theaccurate separation of sources. For highly correlated sources, the identification of specific markers is still the best way for more accurate source apportionment. There are several works using different analytical techniques in PM chemical and physical characterization to supply information forsource apportionment models. The choice amongavailable techniquesdepends on:particles physical properties, sampling and measuring time, access to facilities andthe costs associated to equipmentacquisition, among other considerations. Despite the numerous analytical techniques described in the literature for PM characterization, laboratories are normally limited to in-house available techniques, which raisesthequestion if a giventechnique is suitable for the purpose of a specific experimental work. In this work, the state of art on available technologies for PM characterizationis stablished anda guide to choose the most appropriate technique(s)for a specific study is proposed. A new approach is also proposed to identify the most appropriated sourcesassociated to the factors revealed by the Positive Matrix Factorization modelling by characterizing inorganic and organic chemical species and usingpollutant roses. PMsamples werecollected in a coastal, urban/industrialized region in Brazil andanalyzed by EDXRF, TD-GC-MS and TOC for the characterization of metals, PAHs, EC and OC. This region presents an atypical iron-rich atmosphere due to the presence of pelletizing and steelmaking industries. The proposed methodology revealed that consolidated markers for vehicular: elemental carbon(EC) and organic carbon (OC), sea salt: chloride (Cl) and sodium (Na), and industrial: iron (Fe) sources, were also associated to other sources. Cl,a typical marker of sea salt,was also attributed to industrial sintering activities. Some PMF factors showed high OC loadings, a typical marker for both vehicular exhaust and coal burning. The definitionof the most appropriate source for those factors was only possible due to the assessment of the pollutantroses. Potassium (K), a usual marker of biomass burning, was predominantly associated to winds from an industrial parkplaced at Northeast of the sampling sites and, therefore, most likely associated to sintering emissions. Some PAHs such as naphtalene, chrysene, phenanthrene, fluorine and acenaphtylene were keymarkers allowing the apportionment of sources with similar inorganic chemical profiles, among them theindustrialsintering, pelletizing and biomass burning. viiResults showedthat combining both organic and inorganic chemical markers with pollutant roses for identification of the directionality of predominant sources improved the interpretation of PMF factor numbers in source apportionment studies.In addition, theResonant Synchrotron X-ray Diffraction (RSr-XRD) technique wasconducted at the Laboratório Nacional de Luz Synchrotron(LNLS) in Campinas, Brazil, to analyzesettleable particles (SP),totalsuspended particulate matter(TSP), PM10, andPM2.5samples showinghigh levels of iron-based crystalline phases. In comparison to the use of chemical elemental species, the identification of the crystalline phases provided an enhanced approach to classify specific iron-based source markers. α-Fe2O3, metallic Fe, FeS2andK2Fe2O4areassociated, respectively, toiron ore, pelletizing, and sintering; blast furnaces and steelmaking; coal deposits; andsintering emissions. The attribution of crystal rather than elemental composition in the identification of sources improvedthe accuracy of source apportionment studies.Compounds such as K2Fe2O4 andNH4ClO4 arespecificallylinked to thesintering process, mainly formed during raw materials furnace roasting. Uncommonsulfates crystalssuch as FeAl2(SO4)4.22H2O and (NH4)3Fe(SO4)3 present in the PM2.5 samples showed the high influence of α-Fe2O3in the atmospheric photo-reduction of Fe into sulfates. Results also showedhigh influence of other sourcesthan seawith a highClcontribution, such as sintering and coke ovens. Therefore, we believe that the use of receptor models in tandem with source profiles defined bycrystalline phases, elemental species, andorganic compounds, such as the PAHs, can improve distinction of highly correlated sources.