Poluição e a densidade de vegetação: BTEX em algumas áreas públicas de Curitiba - PR, Brasil

The occurrence of benzene, toluene, ethylbenzene, and xylenes (BTEX) in some public areas of Curitiba-PR, Brazil, was evaluated. Their concentrations were then related to the vegetation's density in each area. Average benzene concentrations varied from 3.9 to 6.1 μg m-3, with higher values occurring in poorly dense vegetation areas. For toluene, average concentrations ranged from 6.5 to 7.2 μg m-3. The effect of such pollutants was evaluated by means of a bio indicator, Tillandsia stricta. Variation in total chlorophyll content and in stomatic density were detected in some samples and may be related to the BTEX concentrations found in the studied areas

Molecular composition of organic aerosols in central Amazonia: An ultra-high-resolution mass spectrometry study

The Amazon Basin plays key role in atmospheric chemistry, biodiversity and climate change. In this study we applied nanoelectrospray (nanoESI) ultra-high-resolution mass spectrometry (UHRMS) for the analysis of the organic fraction of PM2.5 aerosol samples collected during dry and wet seasons at a site in central Amazonia receiving background air masses, biomass burning and urban pollution. Comprehensive mass spectral data evaluation methods (e.g. Kendrick mass defect, Van Krevelen diagrams, carbon oxidation state and aromaticity equivalent) were used to identify compound classes and mass distributions of the detected species. Nitrogen-and/or sulfur-containing organic species contributed up to 60% of the total identified number of formulae. A large number of molecular formulae in organic aerosol (OA) were attributed to later-generation nitrogen-and sulfur-containing oxidation products, suggesting that OA composition is affected by biomass burning and other, potentially anthropogenic, sources. Isoprene-derived organosulfate (IEPOX-OS) was found to be the most dominant ion in most of the analysed samples and strongly followed the concentration trends of the gas-phase anthropogenic tracers confirming its mixed anthropogenic-biogenic origin. The presence of oxidised aromatic and nitro-aromatic compounds in the samples suggested a strong influence from biomass burning especially during the dry period. Aerosol samples from the dry period and under enhanced biomass burning conditions contained a large number of molecules with high carbon oxidation state and an increased number of aromatic compounds compared to that from the wet period. The results of this work demonstrate that the studied site is influenced not only by biogenic emissions from the forest but also by biomass burning and potentially other anthropogenic emissions from the neighbouring urban environments. © 2016 Author(s)

Human exposure to hydrogen sulphide concentrations near wastewater treatment plants

The hydrogen sulphide (H2S) levels from wastewater treatment plants (WWTPs) in Curitiba, Brazil have been quantified for the first time. H2S generated by anaerobic decomposition of organic matter in WWTPs is a cause for concern because it is an air pollutant, which can cause eye and respiratory irritation, headaches, and nausea. Considering the requirement for WWTPs in all communities, it is necessary to assess the concentrations and effects of gases such as H2S on populations living and/or working near WWTPs. The primary objective of this study was to evaluate the indoor and outdoor concentration of H2S in the neighbourhood of two WWTPs located in Curitiba, as well as its human health impacts. Between August 2013 and March 2014 eight sampling campaigns were performed using passive samplers and the analyses were carried out by spectrophotometry, presenting mean concentrations ranging from 0.14 to 32 μg m− 3. Eleven points at WWTP-A reported H2S average concentrations above the WHO recommendation of 10 μg m− 3, and 15 points above the US EPA guideline of 2 μg m− 3. At WWTP-B the H2S concentration was above US EPA guideline at all the sampling points. The I/O ratio on the different sampling sites showed accumulation of indoor H2S in some instances and result in exacerbating the exposure of the residents. The highest H2S concentrations were recorded during the summer in houses located closest to the sewage treatment stations, and towards the main wind direction, showing the importance of these factors when planning a WWTP. Lifetime risk assessments of hydrogen sulphide exposure showed a significant non-carcinogenic adverse health risk for local residents and workers, especially those close to anaerobic WWTPs. The data indicated that WWTPs operated under these conditions should be recognized as a significant air pollution source, putting local populations at risk

The Amazon Tall Tower Observatory (ATTO): Overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region, as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at five to eight different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity). Aerosol optical, microphysical, and chemical measurements are being made above the canopy as well as in the canopy space. They include aerosol light scattering and absorption, fluorescence, number and volume size distributions, chemical composition, cloud condensation nuclei (CCN) concentrations, and hygroscopicity. In this paper, we discuss the scientific context of the ATTO observatory and present an overview of results from ecological, meteorological, and chemical pilot studies at the ATTO site. © Author(s) 2015

Partículas magnéticas: ferrita de ítrio 'Y IND. 3''FE IND. 5''O IND. 12' (YIG) recoberta com sílica ('SIO IND. 2')

Partículas magnéticas de ferrita de Ítrio (YIG) foram preparadas através da heterocoagulação da sílica sobre a ferrita de ítrio. A ferrita de ítrio foi obtida através do processo de nucleação homogênea, controlando a rota química a partir da hidrólise de cátions em meio ácido. A heterocoagulação foi induzida pela hidrólise do tetraetilortosilicato (TEOS) em diferentes meios de dispersão da ferrita de ítrio. Os produtos dispersos foram calcinados e caracterizados por magnometria de amostra vibrante, espectroscopia fotoeletrônica de raios X, microscopias eletrônicas de varredura e de transmissão, difração de elétrons, análise térmica diferencial, difratometria de raios X e mobilidade eletroforética. A camada de sílica que recobre a ferrita de ítrio foi identificada por microscopia eletrônica de transmissão. Difração de elétrons permitiu distinguir a fase policristalina da ferrita de ítrio e a sílica. A ausência dos picos de Fe e Y no espectro de XPS das partículas confirmam que o processo de heterocoagulação foi efetivo. Comparando as propriedades magnéticas da ferrita de ítrio e do sistema sílica/ferrita de ítrio infere-se que as propriedades de magnetização de saturação (Ms) e de campo coercivo (Hc) variaram em função da camada de sílica.Yttrium iron garnet (YIG) particles were coated with silica for control of their synthesis, improving the performance of system and stabilization of magnetic properties. Well-defined magnet particles were prepared by heterocoagulating silica on yttrium iron garnet. Yttrium iron garnet was obtained by homogeneous nucleation process, controlling the chemical routes from cation hydrolysis in acid medium. The heterocoagulation was induced by hydrolysis of tetraethylorthosilicate (TEOS) in appropriate yttrium iron garnet dispersion medium. Dispersed calcinated product was and characterized by vibrating sample magnetometry, X-ray photoemission spectroscopy, transmission and scanning electron microscopies, small area electron diffraction, differential thermal analysis, X-ray diffractometry and electrophoretic mobility. The pure systems YIG and Silica particles dispersions show appropriated physical-chemistry characteristics to be heterocoagulated. The shell of silica on YIG was identified by transmission electron microscopy and small area electron diffraction allowed to distinguish both silica and polycrystalline YIG phases. The absence of Fe and Y peaks on the particle surface XPS measurements confirmed that the heterocoagulation process was carried out by X-ray photoemission spectroscopy Comparing the magnetic measures of the YIG and silica on YIG samples, the magnetic properties of Ms were reduced and of Hc varied in function of the cover layer.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP