993 resultados para sulfur dioxide


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Pós-graduação em Engenharia Mecânica - FEG

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This paper proposes an analysis of two major polluting elements of the atmosphere of São Paulo city, carbon monoxide (CO) and sulfur dioxide (SO2). This study was performed through analysis of data on the quality of air, by means of published reports and records obtained by experiment using measuring rate monitor for CO2. Atmospheric data were collected and sorted. From this work it was possible to identify the concentration of carbon dioxide in the center of São Paulo on September 14, 2012 using the infrared gas analyzer (IRGA). From the ratios of carbon monoxide and sulfur dioxide spatially analyzed could identify major emitters by comparing records of pollutants and their origin. The analysis makes it possible to map the intensity of air pollution in urban areas, identifying the polluting elements, their issuers and thereby contributes to the current understanding of atmospheric features, bringing a geographical spatial analysis of air pollutants in São Paulo, contributing to awareness of vulnerabilities, enabling a useful tool for planning and maintenance of the urban environment related public policies

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Air pollution is an environmental issue worldwide and frequently cause negative effects on population health and ecosystems on cities. The relationship between climate and atmospheric pollution can be used as a surrogate to the intensity of air pollution. The present and quantity of some gases can be used as indicators to air quality: particulate matter (PM), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), and nitrogen dioxide (NO2). Among those gases, CO has its major source within the cities, where automobiles are the main emitter. But measure pollutant concentration are challenging, sometimes because the lack of good equipments due to high costs and of the large variability of models that varies in precision, way of measure and distribution of sellers. Modeling are useful when there are an intend to evaluate air pollution, its sources and evaluate scenarios. This work aims to use CAL3QHCR model developed by the U.S Environmental Protection Agency (EPA) to generate predictive surfaces of CO concentration distribution on a site within Campinas city, located in São Paulo state, Brazil. CAL3QHCR model use data urban automobile circulation to generate spatial results for CO distribution. We observed that the pollution concentration was lower on our modeling than the concentrations measured by Companhia Ambiental do Estado de São Paulo (CETESB), the main environmental company on the São Paulo state. Also the correlation between average estimates of our model and the measure by CETESB was weak, indicating that the model used on this study need to be or better parameterized, or the scale we measured of CO emissions need to be rescaled. Although the model failed to correlate to CETESB data, maybe one that explore the estimated emissions distributed within the sites to understand spatial distributions of CO on the regions. Also, the generated information can also be used to other studies, and come to be useful to explain heat island

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Abstract A fuzzy linguistic model based on the Mamdani method with input variables, particulate matter, sulfur dioxide, temperature and wind obtained from CETESB with two membership functions each was built to predict the average hospitalization time due to cardiovascular diseases related to exposure to air pollutants in São José dos Campos in the State of São Paulo in 2009. The output variable is the average length of hospitalization obtained from DATASUS with six membership functions. The average time given by the model was compared to actual data using lags of 0 to 4 days. This model was built using the Matlab v. 7.5 fuzzy toolbox. Its accuracy was assessed with the ROC curve. Hospitalizations with a mean time of 7.9 days (SD = 4.9) were recorded in 1119 cases. The data provided revealed a significant correlation with the actual data according to the lags of 0 to 4 days. The pollutant that showed the greatest accuracy was sulfur dioxide. This model can be used as the basis of a specialized system to assist the city health authority in assessing the risk of hospitalizations due to air pollutants.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The Brazilian wine industry has a remarkable characteristic that distinguishes from other markets, while the foreign market only accepts products originating from European varieties (Vitis vinifera), in Brazil, products originating from American varieties (Vitis labrusca and Vitis bourquina) and hybrids are also accepted. Dry and sweet varietal wines from varieties Bordô (dry and sweet), Isabel (sweet) e Máximo (dry) were analyzed, by the following chemical standard analyses: alcohol content; density; total and reduced dry matter; alcohol/reduced dry extract ratio; reducing sugars; total, volatile and fixed acidity; pH; total and free sulfur dioxide; and energy value. All analyzed wines presented results within the parameters set forth by Brazilian law, a positive fact, once they are commercialized. The varietal wine Máximo presented a low content of total and free sulfur dioxide, which may cause future problems with its sanity.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The influence of the temperature and reaction time on the sulfation process of a dolomite is investigated in this paper. The sulfation effectiveness was evaluated and correlated with changes in the physical characteristics of a Brazilian dolomite during the reactive process. Calcination and sulfation experiments were performed under isothermal conditions for dolomite samples with average particle sizes of 545 mu m at temperatures of 750 degrees C, 850 degrees C and 950 degrees C at different times of sulfation. Thermogravimetric tests were applied to establish the reactivity variation of the dolomite in function of the time in the sulfation reaction and evaluate the methodology of the samples preparation. Porosimetry tests were performed to study the pore blockage of dolomite during the sulfation reaction. The highest values of BET surface area were 25.55 m(2)/g, 29.55 m(2)/g and 12.62 m(2)/g for calcined samples and after their sulfation processes, conversions of 51.5%, 61.9% and 42.8% were obtained at 750 degrees C, 850 degrees C and 950 degrees C, respectively. Considering the process as a whole, the best fit was provided by a first-order exponential decay equation. Moreover, the results have shown that it is possible to quantify the decreasing in the dolomite reactivity for sulfur dioxide sorption and understand the changes in the behavior of the sulfation process of limestones when applied to technologies, as fluidized bed combustor, in which sulfur dioxide is present. (C) 2011 Elsevier B. V. All rights reserved.

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Over the last three decades, international agricultural trade has grown significantly. Technological advances in transportation logistics and storage have created opportunities to ship anything almost anywhere. Bilateral and multilateral trade agreements have also opened new pathways to an increasingly global market place. Yet, international agricultural trade is often constrained by differences in regulatory regimes. The impact of “regulatory asymmetry” is particularly acute for small and medium sized enterprises (SMEs) that lack resources and expertise to successfully operate in markets that have substantially different regulatory structures. As governments seek to encourage the development of SMEs, policy makers often confront the critical question of what ultimately motivates SME export behavior. Specifically, there is considerable interest in understanding how SMEs confront the challenges of regulatory asymmetry. Neoclassical models of the firm generally emphasize expected profit maximization under uncertainty, however these approaches do not adequately explain the entrepreneurial decision under regulatory asymmetry. Behavioral theories of the firm offer a far richer understanding of decision making by taking into account aspirations and adaptive performance in risky environments. This paper develops an analytical framework for decision making of a single agent. Considering risk, uncertainty and opportunity cost, the analysis focuses on the export behavior response of an SME in a situation of regulatory asymmetry. Drawing on the experience of fruit processor in Muzaffarpur, India, who must consider different regulatory environments when shipping fruit treated with sulfur dioxide, the study dissects the firm-level decision using @Risk, a Monte Carlo computational tool.

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Urban centers significantly contribute to anthropogenic air pollution, although they cover only a minor fraction of the Earth's land surface. Since the worldwide degree of urbanization is steadily increasing, the anthropogenic contribution to air pollution from urban centers is expected to become more substantial in future air quality assessments. The main objective of this thesis was to obtain a more profound insight in the dispersion and the deposition of aerosol particles from 46 individual major population centers (MPCs) as well as the regional and global influence on the atmospheric distribution of several aerosol types. For the first time, this was assessed in one model framework, for which the global model EMAC was applied with different representations of aerosol particles. First, in an approach with passive tracers and a setup in which the results depend only on the source location and the size and the solubility of the tracers, several metrics and a regional climate classification were used to quantify the major outflow pathways, both vertically and horizontally, and to compare the balance between pollution export away from and pollution build-up around the source points. Then in a more comprehensive approach, the anthropogenic emissions of key trace species were changed at the MPC locations to determine the cumulative impact of the MPC emissions on the atmospheric aerosol burdens of black carbon, particulate organic matter, sulfate, and nitrate. Ten different mono-modal passive aerosol tracers were continuously released at the same constant rate at each emission point. The results clearly showed that on average about five times more mass is advected quasi-horizontally at low levels than exported into the upper troposphere. The strength of the low-level export is mainly determined by the location of the source, while the vertical transport is mainly governed by the lifting potential and the solubility of the tracers. Similar to insoluble gas phase tracers, the low-level export of aerosol tracers is strongest at middle and high latitudes, while the regions of strongest vertical export differ between aerosol (temperate winter dry) and gas phase (tropics) tracers. The emitted mass fraction that is kept around MPCs is largest in regions where aerosol tracers have short lifetimes; this mass is also critical for assessing the impact on humans. However, the number of people who live in a strongly polluted region around urban centers depends more on the population density than on the size of the area which is affected by strong air pollution. Another major result was that fine aerosol particles (diameters smaller than 2.5 micrometer) from MPCs undergo substantial long-range transport, with about half of the emitted mass being deposited beyond 1000 km away from the source. In contrast to this diluted remote deposition, there are areas around the MPCs which experience high deposition rates, especially in regions which are frequently affected by heavy precipitation or are situated in poorly ventilated locations. Moreover, most MPC aerosol emissions are removed over land surfaces. In particular, forests experience more deposition from MPC pollutants than other land ecosystems. In addition, it was found that the generic treatment of aerosols has no substantial influence on the major conclusions drawn in this thesis. Moreover, in the more comprehensive approach, it was found that emissions of black carbon, particulate organic matter, sulfur dioxide, and nitrogen oxides from MPCs influence the atmospheric burden of various aerosol types very differently, with impacts generally being larger for secondary species, sulfate and nitrate, than for primary species, black carbon and particulate organic matter. While the changes in the burdens of sulfate, black carbon, and particulate organic matter show an almost linear response for changes in the emission strength, the formation of nitrate was found to be contingent upon many more factors, e.g., the abundance of sulfuric acid, than only upon the strength of the nitrogen oxide emissions. The generic tracer experiments were further extended to conduct the first risk assessment to obtain the cumulative risk of contamination from multiple nuclear reactor accidents on the global scale. For this, many factors had to be taken into account: the probability of major accidents, the cumulative deposition field of the radionuclide cesium-137, and a threshold value that defines contamination. By collecting the necessary data and after accounting for uncertainties, it was found that the risk is highest in western Europe, the eastern US, and in Japan, where on average contamination by major accidents is expected about every 50 years.

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Am vertikalen Windkanal der Johannes Gutenberg-Universität Mainz wurden physikalische und chemische Bereifungsexperimente durchgeführt. Dabei lagen die Umgebungstemperaturen bei allen Experimenten zwischen etwa -15 und -5°C und der Flüssigwassergehalt erstreckte sich von 0,9 bis etwa 1,6g/m³, typische Bedingungen für Mischphasenwolken in denen Bereifung stattfindet. Oberflächentemperaturmessungen an wachsenden hängenden Graupelpartikeln zeigten, dass während der Experimente trockene Wachstumsbedingungen herrschten.rnZunächst wurde das Graupelwachstum an in einer laminaren Strömung frei schwebenden Eispartikeln mit Anfangsradien zwischen 290 und 380µm, die mit flüssigen unterkühlten Wolkentröpfchen bereift wurden, studiert. Ziel war es, den Kollektionskern aus der Massenzunahme des bereiften Eispartikels und dem mittleren Flüssigwassergehalt während des Wachstumsexperimentes zu bestimmen. Die ermittelten Werte für die Kollektionskerne der bereiften Eispartikel erstreckten sich von 0,9 bis 2,3cm³/s in Abhängigkeit ihres Kollektorimpulses (Masse * Fallgeschwindigkeit des bereifenden Graupels), der zwischen 0,04 und 0,10gcm/s lag. Bei den Experimenten zeigte sich, dass die hier gemessenen Kollektionskerne höher waren im Vergleich mit Kollektionskernen flüssiger Tropfen untereinander. Aus den aktuellen Ergebnissen dieser Arbeit und der vorhandenen Literaturwerte wurde ein empirischer Faktor entwickelt, der von dem Wolkentröpfchenradius abhängig ist und diesen Unterschied beschreibt. Für die untersuchten Größenbereiche von Kollektorpartikel und flüssigen Tröpfchen können die korrigierten Kollektionskernwerte in Wolkenmodelle für die entsprechenden Größen eingebunden werden.rnBei den chemischen Experimenten zu dieser Arbeit wurde die Spurenstoffaufnahme verschiedener atmosphärischer Spurengase (HNO3, HCl, H2O2, NH3 und SO2) während der Bereifung untersucht. Diese Experimente mussten aus technischen Gründen mit hängenden Eispartikeln, dendritischen Eiskristallen und Schneeflocken, bereift mit flüssigen Wolkenlösungströpfchen, durchgeführt werden.rnDie Konzentrationen der Lösung, aus der die Wolkentröpfchen mit Hilfe von Zweistoffdüsen erzeugt wurden, lagen zwischen 1 und 120mg/l. Für die Experimente mit Ammoniak und Schwefeldioxid wurden Konzentrationen zwischen 1 und 22mg/l verwendet. Das Schmelzwasser der bereiften hängenden Graupel und Schneeflocken wurden ionenchromatographisch analysiert und zusammen mit der bekannten Konzentration der bereifenden Wolkentröpfchen konnte der Retentionskoeffizient für jeden Spurenstoff bestimmt werden. Er gibt die Menge an Spurenstoff an, die bei der Phasenumwandlung von flüssig zu fest in die Eisphase übergeht. Salpetersäure und Salzsäure waren nahezu vollständig retiniert (Mittelwerte der gesamten Experimente entsprechend 99±8% und 100±9%). Für Wasserstoffperoxid wurde ein mittlerer Retentionskoeffizient von 65±17% bestimmt. rnDer mittlere Retentionskoeffizient von Ammoniak ergab sich unabhängig vom Flüssigwassergehalt zu 92±21%, während sich für Schwefeldioxid 53±10% für niedrige und 29±7% für hohe Flüssigphasenkonzentrationen ergaben. Bei einigen der untersuchten Spurenstoffe wurde eine Temperaturabhängigkeit beobachtet und wenn möglich durch Parametrisierungen beschrieben.rn

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The volcanic aerosol plume resulting from the Eyjafjallajökull eruption in Iceland in April and May 2010 was detected in clear layers above Switzerland during two periods (17–19 April 2010 and 16–19 May 2010). In-situ measurements of the airborne volcanic plume were performed both within ground-based monitoring networks and with a research aircraft up to an altitude of 6000 m a.s.l. The wide range of aerosol and gas phase parameters studied at the high altitude research station Jungfraujoch (3580 m a.s.l.) allowed for an in-depth characterization of the detected volcanic aerosol. Both the data from the Jungfraujoch and the aircraft vertical profiles showed a consistent volcanic ash mode in the aerosol volume size distribution with a mean optical diameter around 3 ± 0.3 μm. These particles were found to have an average chemical composition very similar to the trachyandesite-like composition of rock samples collected near the volcano. Furthermore, chemical processing of volcanic sulfur dioxide into sulfate clearly contributed to the accumulation mode of the aerosol at the Jungfraujoch. The combination of these in-situ data and plume dispersion modeling results showed that a significant portion of the first volcanic aerosol plume reaching Switzerland on 17 April 2010 did not reach the Jungfraujoch directly, but was first dispersed and diluted in the planetary boundary layer. The maximum PM10 mass concentrations at the Jungfraujoch reached 30 μgm−3 and 70 μgm−3 (for 10-min mean values) duri ng the April and May episode, respectively. Even low-altitude monitoring stations registered up to 45 μgm−3 of volcanic ash related PM10 (Basel, Northwestern Switzerland, 18/19 April 2010). The flights with the research aircraft on 17 April 2010 showed one order of magnitude higher number concentrations over the northern Swiss plateau compared to the Jungfraujoch, and a mass concentration of 320 (200–520) μgm−3 on 18 May 2010 over the northwestern Swiss plateau. The presented data significantly contributed to the time-critical assessment of the local ash layer properties during the initial eruption phase. Furthermore, dispersion models benefited from the detailed information on the volcanic aerosol size distribution and its chemical composition.

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Mount Etna, Italy, is one of the most active volcanoes in the world, and is also regarded as one of the strongest volcanic sources of sulfur dioxide (SO2) emissions to the atmosphere. Since October 2004, an automated ultraviolet (UV) spectrometer network (FLAME) has provided ground-based SO2 measurements with high temporal resolution, providing an opportunity to validate satellite SO2 measurements at Etna. The Ozone Monitoring Instrument (OMI) on the NASA Aura satellite, which makes global daily measurements of trace gases in the atmosphere, was used to compare SO2 amount released by the volcano during paroxysmal lava-fountaining events from 2004 to present. We present the first comparison between SO2 emission rates and SO2 burdens obtained by the OMI transect technique and OMI Normalized Cloud-Mass (NCM) technique and the ground-based FLAME Mini-DOAS measurements. In spite of a good data set from the FLAME network, finding coincident OMI and FLAME measurements proved challenging and only one paroxysmal event provided a good validation for OMI. Another goal of this work was to assess the efficacy of the FLAME network in capturing paroxysmal SO2 emissions from Etna, given that the FLAME network is only operational during daylight hours and some paroxysms occur at night. OMI measurements are advantageous since SO2 emissions from nighttime paroxysms can often be quantified on the following day, providing improved constraints on Etna’s SO2 budget.