Abstract Parmotrema austrosinense (Zahlbr.) Hale lichens were collected from the Pretoria central business district (CBD), as well as three sites to the east of Pretoria; the National Botanical Gardens, the CSIR campus and the suburb of Lynnwood, with the aim of utilising these lichens as biomonitors of air quality to determine the effects of the phasing out of leaded petrol and the simultaneous introduction of manganese anti-knock additives to fuel in South Africa. In addition to lichens, roadside dust and soil samples were collected from the CBD and CSIR campus, and all samples were analysed by flame atomic absorption spectrometry after acid digestion. There was no significant difference (95 % confidence) between the Mn content of lichens from all sampling sites (overall average of 97.1 ± 39.1 μg.g-1, n= 28), which was most likely due to an even suspension of Mn-containing particles arising from soil dust. Additional contributions to Mn loading as a result of vehicle emissions were currently not evident. For all non-CBD sites, higher Pb levels were found in lichens which were nearer to busy roads, suggesting an historical impact by vehicular emissions of Pb arising from leaded petrol usage. The Pb concentrations in lichens found in the CBD (average of 181.1 ± 98.0 μg.g-1, n=10) were significantly higher (95 % confidence limits) than those of lichens growing outside of the CBD area (average of 41.5 ± 36.4 μg.g-1, n=18), and the Pb levels were higher than those of Mn, which was contrary to that found in sites outside the CBD.

No description available.

Diss. (sammanfattning) Umeå : Umeå universitet, 2006. / Härtill 5 uppsatser.

Thesis (M. Sc.)--Athens Technological Institute, 1963. / Bibliography: p. 168-169.

Stringent pollutant regulations on diesel-powered vehicles have resulted in the development of new technologies to reduce emission of nitrogen oxides (NOx). The urea Selective Catalyst Reduction (SCR) system and Lean NOx Trap (LNT) have become the two promising solutions to this problem. Whilst the LNT results in a fuel penalty due to periodic regeneration, the SCR system with aqueous urea solution or ammonia gas reductants could provide a better solution with higher NOx reduction efficiency. This thesis describes an experimental investigation which has been designed for comparing the effect NOx abatement of a SCR system with AdBlue urea spray and ammonia gas at 5% and 4% concentration. For this study, a SCR exhaust system comprising of a diesel particulate filter (DPF), a diesel oxidation catalyst (DOC) and SCR catalysts was tested on a steady state, direct injection 1998 cc diesel engine. It featured an expansion can, nozzle and diffuser arrangement for a controlled flow profile for CFD model validation. Four different lengths of SCR catalyst were tested for a space velocity study. Chemiluminescence (CLD) based ammonia analysers have been used to provide high resolution NO, NO2 and NH3 measurements across the SCR exhaust system. By measuring at the exit of the SCR bricks, the NO and NO2 profiles within the bricks were found. Comparison of the measurements between spray and gas lead to insights of the behaviour of the droplets upstream and within the SCR bricks. From the analysis, it was deduced that around half to three quarters of the droplets from the urea spray remain unconverted at the entry of the first SCR brick. Approximately 200 ppm of potential ammonia was released from the urea spray in the first SCR brick to react with NOx. The analysis also shows between 10 to 100 ppm of potential ammonia survived through the first brick in droplet form for cases from NOx-matched spray input to excess spray. Measurements show NOx reduction was complete after the second SCR bricks. Experimental and CFD prediction showed breakthrough of all species for the short brick with gas injection due to the high space velocity. The long brick gas cases predictions gave reasonable agreement with experimental results. NO2 conversion efficiency was found higher than NO which contradicts with the fast SCR reaction kinetics. Transient response was observed in both cases during the NOx reduction, ammonia absorption and desorption process. From the transient analysis an estimate of the ammonia storage capacity of the bricks was derived. The amount of ammonia slippage was obtained through numerical integration of the ammonia slippage curve using an excel spreadsheet. Comparing the time constant for the spray and gas cases, showed a slightly faster time response from the gas for both NOx reduction and ammonia slippage.

Introdução. A presença de partículas metálicas finas na atmosfera urbana é preocupante considerando que um significativo acúmulo desses elementos no ar ambiente tem sido registrado nas últimas décadas. As informações sobre os teores de metais nas emissões de escapamentos dos veículos automotores são bastante limitadas, não sendo encontradas referências nacionais específicas sobre o tema. Objetivo: Caracterizar experimentalmente as frações fina e grossa de partículas (PM10), e os metais que compõem essas partículas emitidas na exaustão dos veículos dos ciclos Otto e Diesel.Método: Foram ensaiados dois veículos do ciclo Otto em um dinamômetro de chassi, seguindo ciclo de condução e sistema de amostragem padronizado pela norma NBR 6601 (2005): e dois veículos do ciclo Diesel, em ensaio de aceleração livre segundo a norma NBR 13037 (2001) e em operação em marcha lenta. As partículas com diâmetro ≤10 foram selecionadas e as frações fina e grossa obtidas por impactação em filtros de policarbonato, sendo sua composição elementar (elementos com Z >10) obtida pela técnica analítica de espectroscopia de raio-X (PIXE). Resultados: Os veículos a µm diesel apresentaram uma emissão média de partículas (PM10) coletada no fluxo sem diluição de aproximadamente 20,166 mg/m3, os veículos a gasolina de 0,411 gm/m3 e a álcool de 0,142 gm/m3 coletadas no fluxo de diluição. Os principais metais identificados na exaustão foram Al, Si, K, Ca, Mn, Fé, Ni, Cu, Zn, Pt e Pb, com algumas variações em função do tipo de combustível e veículo ensaiado. A média das concentrações total de PM10 presente na exaustão dos veículos ensaiados. Conclusão. Os veículos a diesel são os maiores emissores de material particulado, seguidos pelos veículos a gasolina e álcool, respectivamente. A avaliação das partículas amostradas alerta para o fato de que nos três tipos de veículos a maior parte das emissões é pertencente à fração fina. Considerando que os metais identificados podem fixar-se às partículas finas e penetrar no organismo humano e que alguns compostos metálicos, além de apresentarem efeitos carcinogênicos, são também potentes alergogênicos e sensibilizantes, deve ser ressaltada a necessidade de controle destas emissões para veículos em uso no Brasil de modo evitar danos à saúde. / Introduction: The presence of fine metal particles in the urban atmosphere is a big concern considering that a significant accumulation of these elements has been registered during the last decades. Information about metal level in the tailpipe is scarce and specific Brazilian emission references are basically inexistent. Objective. Experimentally characterize fine and coarse PM10 particles and their metal constituents in the combustion exhaust of Otto and Diesel vehicles. Methods. Two Otto vehicles were essayed on a chassis dynamometer following a standard driving cycle using a sampling system in accordance with the NBR 6601 (2005); and two Diesel vehicles were essayed both in free acceleration tests according to the NBR 13037 (2001) standard and at idle rpm. The particles with diameter ≤10 µm were separated in the fine and coarse fraction by impaction in polycarbonate filters, and their elementary composition were determined by X-ray spectrometry (PIXE). Results. The diesel vehicles presented a PM10 particle average emission of 0,207 g/m3, whereas the gasoline vehicle presented 0,411 gm/m3 and the ethanol vehicle presented an average emission of 0,142 gm/m3 . The main metals identified in the emission were Al, Si, K, Ca, Mn, Fé, Ni, Cu, Zn, Pt and Pb, with some variations in function of both the type of fuel and vehicle essayed. The average concentration of the fine fraction corresponded to more than 60% of the total concentration of PM10 in the vehicle exhaust. Conclusion. The diesel vehicles are the highest particulate emitters, followed by the gasoline vehicles and ethanol vehicles in this order. The evaluation of the sampled particles alerts for the fact that for all the three types of vehicles the major part of the particle emitted is in the fine fraction of particle size range. Considering, that the metals identified by the analyses can penetrate in the human organism by adhering to fine particles. It is a fact that some metallic compounds in addition to presenting carcinogenic effects are also powerful allergen and sensitizer, it should be emphasized the need of in use vehicle emission control as a means of voiding harms to the population health.

INTRODUÇÃO: A poluição atmosférica é reconhecida como fonte de possíveis agravos à saúde. Estudos tem demonstrado uma clara associação entre aumento da concentração dos poluentes atmosféricos, especialmente o material particulado proveniente de resíduos de exaustão de motores movidos a diesel, com morbidade e mortalidade respiratória e cardíaca na população geral. Até o presente momento, sabe-se que o material particulado possui ações deletérias sobre as vias aéreas superiores e inferiores; contudo, ainda não são completamente conhecidas as ações tóxicas isoladas das diferentes frações do material particulado do diesel. OBJETIVO: O presente estudo teve por finalidade avaliar o grau de toxicidade das frações orgânicas de baixa, média e alta polaridade e da fração inorgânica do material particulado proveniente da emissão de motores movidos a óleo diesel sobre o epitélio mucociliar. MÉTODOS: Para tanto, utilizou-se como modelo experimental a preparação do palato da rã, que possui um epitélio similar ao das vias aéreas de mamíferos. O estudo foi dividido em duas etapas: Fase I - Quarenta palatos foram utilizados com intuito de titular a concentração de material particulado bruto capaz de promover um aumento significante no tempo relativo de transporte mucociliar. Fase II - Uma vez definida a concentração efetiva, cinqüenta palatos foram expostos aos seguintes tratamentos: material particulado bruto do diesel (sem nenhum tipo de tratamento), material particulado do diesel tratado com hexano (solvente que reduz a quantidade dos compostos orgânicos de baixa polaridade), material particulado do diesel tratado metanol (solvente que reduz a quantidade de compostos orgânicos de polaridade intermediária, gerando aumento relativo da concentração de orgânicos de baixa e alta polaridade) e material particulado do diesel tratado ácido nítrico (solvente que reduz a concentração de compostos inorgânicos, gerando aumento relativo da fração orgânica como um todo). Para fins de controle utilizou-se um grupo com ringer-rã. As variáveis analisadas foram: tempo relativo de transporte mucociliar, freqüência de batimento ciliar e análise histológica, na qual foram avaliados o volume proporcional de muco ácido, muco neutro, muco misto, de cílios, vacúolos, dos núcleos celulares e interstício e espessura epitelial. RESULTADOS: Fase I: A concentração de material particulado bruto capaz de promover um aumento significativo no tempo relativo de transporte mucociliar, e também do volume proporcional de muco ácido (p<0,05), correspondeu a 12mg/L. Fase II: Observou-se: a) aumento significativo no tempo relativo de transporte mucociliar e redução significativa do volume proporcional de muco neutro no grupo ácido nítrico; b) maior volume proporcional de muco ácido no grupo metanol (p<0,05); c) ausência de diferenças entre o grupo controle e o grupo hexano, tanto na análise histológica quanto no tempo relativo de transporte mucociliar. CONCLUSÃO: Os dados obtidos sugerem que os compostos orgânicos de baixa polaridade do material particulado proveniente da emissão de motores movidos a óleo diesel desempenham um importante papel na toxicidade aguda ao epitélio ciliado / INTRODUCTION: Air pollution is recognized as a source of potential health problems. Studies have shown a clear association between increasing concentration of atmospheric pollutants, especially particulate matter from waste exhaust of diesel engines, and respiratory and cardiac morbidity and mortality in the general population. To date, it is well known that particulate matter from diesel exhaust has deleterious actions on upper and lower airways; however, the isolated toxic actions of different fractions of the particulate matter are not yet fully understood. OBJECTIVE: This study aimed at evaluating the degree of toxicity of the organic fractions of low, intermediate and high polarity and of the inorganic fraction of particulate matter from diesel engines on the ciliated epithelium. METHODS: The experimental model used was the frog palate preparation, which has a similar epithelium to that found in mammalian airways. The study was divided into two phases: Phase I - Forty palates were used in order to titrate the concentration of intact diesel particulate matter able to elicit a significant increase in the relative time of mucociliary transport. Phase II Once defined the optimal concentration, fifty palates were exposed to dilutions with the following treatments: intact diesel particulate material (without any treatment), particulate matter from diesel exhaust treated with hexane (solvent which reduces the amount of organic compounds of low polarity), particulate matter from diesel exhaust treated with methanol (solvent which reduces the amount of organic compounds with intermediate polarity, generating a relative increase in concentration of organic compounds with low and high polarity) and particulate matter from diesel exhaust treated with nitric acid (solvent which removes inorganic compounds, eliciting a relative increase of the organic fraction as a whole). For control purposes, a group of frog-ringer was used. The following variables were analyzed: relative time of mucociliary transport, ciliary beating frequency and histological analysis, which evaluated proportional volume of acid mucus, neutral and mixed mucus, cilia, vacuoles, cell nuclei and interstice, and epithelial thickness. RESULTS: Phase I: The effective concentration of intact diesel particulate matter in eliciting a significant increase in the relative time of mucociliary transport, and a proportional increase of acid mucus volume (p<0.05), corresponded to 12mg/L. Phase II: a) The nitric acid treatment caused a significant increase in the relative time of mucociliary transport, and decrease in the proportional volume of neutral mucus. b) A higher proportional volume of acid mucus was found in the methanol group (p<0.05). c) There were no differences between control and hexane groups regarding histological findings and relative time of mucociliary transport. CONCLUSION: The results suggest that organic compounds of low polarity from diesel engines exhaust particles play an important role in the acute toxicity on the ciliated epithelium

Introdução. A presença de partículas metálicas finas na atmosfera urbana é preocupante considerando que um significativo acúmulo desses elementos no ar ambiente tem sido registrado nas últimas décadas. As informações sobre os teores de metais nas emissões de escapamentos dos veículos automotores são bastante limitadas, não sendo encontradas referências nacionais específicas sobre o tema. Objetivo: Caracterizar experimentalmente as frações fina e grossa de partículas (PM10), e os metais que compõem essas partículas emitidas na exaustão dos veículos dos ciclos Otto e Diesel.Método: Foram ensaiados dois veículos do ciclo Otto em um dinamômetro de chassi, seguindo ciclo de condução e sistema de amostragem padronizado pela norma NBR 6601 (2005): e dois veículos do ciclo Diesel, em ensaio de aceleração livre segundo a norma NBR 13037 (2001) e em operação em marcha lenta. As partículas com diâmetro &#8804;10 foram selecionadas e as frações fina e grossa obtidas por impactação em filtros de policarbonato, sendo sua composição elementar (elementos com Z >10) obtida pela técnica analítica de espectroscopia de raio-X (PIXE). Resultados: Os veículos a µm diesel apresentaram uma emissão média de partículas (PM10) coletada no fluxo sem diluição de aproximadamente 20,166 mg/m3, os veículos a gasolina de 0,411 gm/m3 e a álcool de 0,142 gm/m3 coletadas no fluxo de diluição. Os principais metais identificados na exaustão foram Al, Si, K, Ca, Mn, Fé, Ni, Cu, Zn, Pt e Pb, com algumas variações em função do tipo de combustível e veículo ensaiado. A média das concentrações total de PM10 presente na exaustão dos veículos ensaiados. Conclusão. Os veículos a diesel são os maiores emissores de material particulado, seguidos pelos veículos a gasolina e álcool, respectivamente. A avaliação das partículas amostradas alerta para o fato de que nos três tipos de veículos a maior parte das emissões é pertencente à fração fina. Considerando que os metais identificados podem fixar-se às partículas finas e penetrar no organismo humano e que alguns compostos metálicos, além de apresentarem efeitos carcinogênicos, são também potentes alergogênicos e sensibilizantes, deve ser ressaltada a necessidade de controle destas emissões para veículos em uso no Brasil de modo evitar danos à saúde. / Introduction: The presence of fine metal particles in the urban atmosphere is a big concern considering that a significant accumulation of these elements has been registered during the last decades. Information about metal level in the tailpipe is scarce and specific Brazilian emission references are basically inexistent. Objective. Experimentally characterize fine and coarse PM10 particles and their metal constituents in the combustion exhaust of Otto and Diesel vehicles. Methods. Two Otto vehicles were essayed on a chassis dynamometer following a standard driving cycle using a sampling system in accordance with the NBR 6601 (2005); and two Diesel vehicles were essayed both in free acceleration tests according to the NBR 13037 (2001) standard and at idle rpm. The particles with diameter &#8804;10 µm were separated in the fine and coarse fraction by impaction in polycarbonate filters, and their elementary composition were determined by X-ray spectrometry (PIXE). Results. The diesel vehicles presented a PM10 particle average emission of 0,207 g/m3, whereas the gasoline vehicle presented 0,411 gm/m3 and the ethanol vehicle presented an average emission of 0,142 gm/m3 . The main metals identified in the emission were Al, Si, K, Ca, Mn, Fé, Ni, Cu, Zn, Pt and Pb, with some variations in function of both the type of fuel and vehicle essayed. The average concentration of the fine fraction corresponded to more than 60% of the total concentration of PM10 in the vehicle exhaust. Conclusion. The diesel vehicles are the highest particulate emitters, followed by the gasoline vehicles and ethanol vehicles in this order. The evaluation of the sampled particles alerts for the fact that for all the three types of vehicles the major part of the particle emitted is in the fine fraction of particle size range. Considering, that the metals identified by the analyses can penetrate in the human organism by adhering to fine particles. It is a fact that some metallic compounds in addition to presenting carcinogenic effects are also powerful allergen and sensitizer, it should be emphasized the need of in use vehicle emission control as a means of voiding harms to the population health.

Revised version, September 2012 / Comments and Discussions : Shinichi NAGAO

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains x, 98 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 76-88).