Chemical characterization and size distribution of atmospheric particles in urban area - preliminary study

The present work is a preliminary study with the aim of characterize the particle size and the chemical composition of aerosols in the Charqueadas County in Rio Grande do Sul State, Brazil, in order to better identify the sources responsible for alterations in the air quality. Seven filters were used for collecting material on thin nucleopore polycarbonate membrane (0,4 µm) during March/1996 to July/1996. X-ray energy dispersive scanning electron microscopy was used to determine the chemical composition of aerosol particles, and 21 elements were then analysed. Particle size distribution was measured by SEM-EDX analysis, and also by automated image technique. Nonhierarchical cluster analysis was applied to identify the types of particles present in the samples. This procedure resulted in the definition of 8 groups of particles containing Fe, Zn, Si, Al, S, Ca, Na and K, that revealed the chemical heterogeneity of aerosols in Charqueadas Country. The particle size analysis showed the predominance (around 80% of all analyzed particles) of the fraction ≤ 10 µm (dia) with the highest concentration of these particles located in the size ≤ 2.0 µm (dia). Data from particle size distribution, including Falk and Ward parameters, were combined with meteorological parameters and subjected to Hierarchical Cluster Analysis and Discriminant Analysis. This procedure allowed particle-based features and meteorological variables to be integrated for potentially better discriminant capability.O presente trabalho consiste em um estudo preliminar com o objetivo de caracterizar o tamanho de partícula e a composição elementar dos aerossóis no Município de Charqueadas no estado do Rio Grande do Sul, Brasil, a fim de identificar melhor as fontes que tem provocado alterações da qualidade do ar. Sete filtros foram coletados em membrana filtro de policarbonato (0,4 µm) no período de Março/96 à Julho/96. Microscopia eletrônica com energia dispersiva de Raio-X foi usado para caracterizar a composição elementar de aerossóis coletados em amostrador de ar. Distribuição de tamanho de partícula foi realizada aplicando além do SEM-EDX, a técnica analisador de imagem automático. Análise de Cluster não hierárquica foi aplicada para identificar os tipos de partículas. Estes dados resultaram na definição de 8 grupos de partículas contendo Fe, Zn, Si, AI, S, Ca, Na e K, revelando heterogeneidade química dos aerossóis no Município de Charqueadas. A distribuição granulométrica mostrou predominância de tamanho ≤ 10 µm, cerca de 80 % do total de partículas analisadas, sendo que o percentual mais elevado foi verificado na fração de 1 µm e 2 µm. Os dados de distribuição granulométrica, juntamente com as variáveis meteorológicas foram avaliados, aplicando Análise de Agrupamento Hierárquico, pelo método de Ward's, e Análise Discriminante. Este procedimento permitiu que as variáveis meteorológicas e as características das partículas fossem integradas para melhor capacidade discriminatória

Estudo das emissões de fontes móveis na região metropolitana de Porto Alegre, Rio Grande do Sul

The present study aims at assessing the influence of pollution from mobile sources on air quality in the Metropolitan Area of Porto Alegre by means of an inventory based on methods applied specifically to vehicular emissions. The study uses the method described by CETESB, based on inventories on vehicular emissions, according to USEPA methodology. Following fuel types were taken into account: gasoline (24% ethanol), alcohol, diesel oil, and CNG (compressed natural gas). Results have shown that gasoline-powered vehicles are still responsible for emitting the highest CO and HC concentrations, while diesel-powered vehicles are the source of highest NOx, MP and SOx concentrations

Geochemical study of submicron particulate matter (PM1) in a metropolitan area

Air pollution has become a major problem in urban areas due to increasing industrialization and urbanization. In this study ambient concentrations of PM1 and metal concentrations as well as source contributions were identified and quantified by using Positive Matrix Factorization (PMF) in receptor modeling in the Metropolitan Area of Porto Alegre, Brazil. The PM1 samples were collected on PTFE filters from December 2012 to December 2014 in two sampling sites. Major ion and trace element concentrations were assessed. The average concentrations were 12.8 and 15.2 µg/m3 for Canoas and Sapucaia do Sul sites, respectively. Major ion contributions of PM1 were secondary pollutants such as sulfate and nitrate. Trace elements, especially Cu, Pb, Zn, Cd, and Ni also made important contributions which are directly associated with anthropogenic contributions. Our results show significantly higher levels in winter than in summer. Most of the PM1 and the analyzed PM species and elements originated from anthropogenic sources, especially road traffic, combustion processes and industrial activities, which are grouped in 7 major contributing sources. A back-trajectory analysis showed that the long-range transport of pollutants was not relevant in relation to the contribution to PM1 and metal concentrations. This work highlights the importance of urban planning to reduce human health exposure to traffic and industrial emissions, combined with awareness-raising actions for citizens concerning the impact of indoor sources

Exposure to polycyclic aromatic hydrocarbons in atmospheric PM1.0 of urban environments: Carcinogenic and mutagenic respiratory health risk by age groups

We investigated the carcinogenic and mutagenic respiratory health risks related to the exposure to atmospheric PAHs in an urban area. Our study focused in the association of these pollutants and their possible effect in human health, principally respiratory and circulatory diseases. Also, we determined a relationship between the inhalation risk of PAHs and meteorological conditions. We validated the hypothesis that in winter PAHs with high molecular weight associated to submicron particles (PM1) may increase exposure risk, especially for respiratory diseases, bronchitis and pneumonia diseases. Moreover, in our study we verified the relationship between diseases and several carcinogenic PAHs (Ind, BbkF, DahA, BaP, and BghiP). These individual PAHs contributed the most to the potential risk of exposure for inhalation of PM1.0. Even at lower ambient concentrations of BaP and DahA in comparison with individual concentrations of other PAHs associated to PM1.0. Mainly, research suggests to include carcinogenic and mutagenic PAHs in future studies of environmental health risk due to their capacity to associate to PM10. Such carcinogenic and mutagenic PAHs are likely to provide the majority of the human exposure, since they originate from dense traffic urban areas were humans congregate

Use of the geophysical method EM 34-3 in the study of groundwater contamination by coal waste and ashes

The main objective of this paper is to evaluate the efficiency of the geophysical technique EM – 34 – 3 in the study of the groundwater contamination by residues from coal processing. It was applied, in the coal waste and ashes disposal site – CH 20, located in the municipal district of Charqueadas, the electromagnetic geophysical method EM – 34 – 3, which measures the electric conductivity of the medium in subsurface. It was noticed that the highest anomalous electrical conductivity values and ions content were placed inside the disposal site with the most significant contamination situated in the phreatic aquifer. Besides, it was verified an incipient pollution plume in the direction of groundwater flow (to SW). The methodology presented good results in the delimitation of the polluted area, supplying a guiding character for posterior sampling campaigns of contamination groundwater degree and indicating the concentrations of the pollutant elements in subsurface. Este trabalho tem por objetivo principal avaliar a eficiência da técnica geofísica EM-34-3 no estudo da contaminação das águas subterrâneas por resíduos do processamento de carvão. Para tanto, foi aplicado, no depósito de rejeitos de carvão e cinzas - CH 20, localizado no município de Charqueadas, o método geofísico eletromagnético EM-34-3, que mede a condutividade elétrica do meio, em subsuperfície. Constatou-se que as mais altas anomalias de condutividade elétrica e concentração de íons estavam localizados dentro da área de disposição com a contaminação mais significante situada no aqüífero freático. Além disso, foi verificada uma pluma de poluição incipiente na direção do fluxo da água subterrânea (para SW). A metodologia empregada apresentou bons resultados para a delimitação da área contaminada, mostrando-se de caráter orientativo para posteriores campanhas de amostragens de águas subterrâneas, a partir das quais serão definidos os níveis de contaminação e indicadas as concentrações dos elementos poluentes em subsuperfície

Aplicação da análise fatorial e do Sig à integração e apresentação dos resultados do estudo da qualidade de água e sedimentos fluviais na região do Baixo Jacuí, RS

Factor analysis and geoprocessing techniques were complementary tools for integration and visual presentation of results from water quality and fluvial sediment studies in Baixo Jacuí region, Rio Grande do Sul State, Brazil. Samples were taken along 18 months in 15 sites along the Jacuí river and main tributaries, especially Conde creek, where there is important anthropogenic contribution associated to coal explotation, processing and waste disposal. The proposed water quality index to the region has facilitated the detection of critical fluvial segments, particularly related to trace elements concentration in Conde creek. In Jacuí river it was not observed a water quality variation, problably in responde to a high dilution capacity. On the other hand, the application of fatorial analysis techniques to sediment data suggested its great sensitivity to assess the main sources of pollution to the water resources in the study region and pointed out the accumulation of pollutants in the sediments, from industrial and coaI processing related sources. This results could be integrated by geoprocessing techniques to facilitate public presentation.Técnicas de análise fatorial e geoprocessamento foram utilizadas como ferramentas complementares para integração, síntese e apresentação visual dos resultados dos estudos de qualidade da água e sedimentos fluviais na região do Baixo Jacuí, RS. A coleta de amostras de água e sedimento foi realizada ao longo de 18 meses, em 15 pontos localizados no rio Jacuí e nos seus principais contribuintes, com ênfase na sub bacia hidrográfica do arroio do Conde, onde é intensificada a contribuição associada à mineração, ao beneficiamento e à disposição de resíduos de carvão. A confecção de um índice de qualidade da água para a região de estudo possibilitou a detecção dos trechos críticos em relação à concentração dos parâmetros analisados, especialmente elementos traço, no arroio do Conde. No Rio Jacuí, não foi observada a variação espacial da qualidade da água, provavelmente em função de sua alta capacidade de diluição. Por outro lado, a aplicação da técnica de análise fatorial aos dados de qualidade dos sedimentos revelou maior sensibilidade deste compartimento na avaliação da influência antropogênica, indicando a acumulação dos poluentes lançados por fontes industriais e relacionadas às atividades do processamento do carvão. Os resultados foram sintetizados e melhor visualizados através da combinação das técnicas de geoprocessamento para a apresentação das conclusões deste estudo, de modo a facilitar sua comunicação para o público em geral

Assessment of the NO2 distribution and relationship with traffic load in the Caribbean coastal city

NO2 ambient concentrations were measured in a coastal Caribbean city. Barranquilla is a Caribbean city located in the North of Colombia that has approximately 1.200.000 inhabitants and possesses a warm, humid climate. In order to obtain the concentration of the contaminant in an adequate resolution, 137 passive diffusion tubes from Gradko© were installed. Diffusion passive tubes prepared with 20% TEA/water were located at the roadside between 1 and 5 m from the kerb edge. The sampling period was two weeks, from 3/16/2019 to 3/30/2019. Samples were analyzed on the UV CARY1 spectrophotometer by Gradko©. Results showed an average of 19.92 ±11.50 µg/m3 , with a maximum and minimum value of 70.27 and 0.57 µg/m3 , respectively. Spatial NO2 correlation with low traffic load was higher than with maximum traffic. The expected results include analyzing the areas of the city with high concentrations of this pollutant that exceed the WHO guidelines in six (6) points. Overall, the multiregression analysis is a very effective method to enrich the understanding of NO2 distributions. It can provide scientific evidence for the relationship between NO2 and traffic, beneficial for developing the targeted policies and measures to reduce NO2 pollution levels in hot spots. This research may subsidize knowledge to serve as a tool for environmental and health authorities

Exposure to nanometric pollutants in primary schools: Environmental implications

School children are highly susceptible to chemicals in the atmosphere. Some studies have demonstrated that the pollution is related to respiratory problems and impaired cognitive development in children. In this context, the objective of this study was to determine nanoparticles and associated species and their origin in fresh air currents in La Salle Canoas School in Rio Grande do Sul (Brazil). Different analyses by using high-resolution transmission electron microscopy with energy-dispersive, X-ray spectroscopy (HR-TEM/SAED/EDS), and the scanning (STEM) mode were carried out. The EDS analysis of the atmospheric particles demonstrated that materials contain a significant proportion of elements such as Cr, Fe, Mn, Ni, and Si and other trace metals Zn, Pb, Zr, Ca, Cu, K, Cr, and Cd from exhaust and non-exhaust. The main source of the particles was emission from internal combustion in motor vehicles, road dust, and brake and tire wear. This emphasizes the importance of urban planning to reduce exposure of children to traffic gas emissions