Thesis (M.S.) in Resource Utilitization--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 39-40).

The contributions of specific polluting sources to both indoor and outdoor atmospheric pollution are difficult to determine, as solid and gaseous products from different combustion sources are often similar. Sometimes, however, a marker compound can be identified that is unique to a pollution source (or at least not present in most other local combustion sources) and which will allow assessment of the contribution of that source to total atmospheric pollution. The aim of this study was to identify suitable marker compounds and methods for the apportionment (assessment of percentage contribution) of specific sources to atmospheric pollution. The sources selected were diesel exhaust emissions in outdoor, and environmental tobacco smoke (ETS) in indoor environments. Studies with controlled (laboratory) atmospheres would be followed by field studies using these methods and markers to produce apportionments for these sources to air pollution in selected environments. Initial analysis of such polluting sources was therefore the qualitative analysis of volatile compounds and particulate associated material, both organic and inorganic. Volatile organic compounds were adsorbed onto various resins, while particulate material was sampled onto various filter paper types. Organics were determined by GC-AED and GC-MS, and elements by ICP-MS.1-Nitropyrene was identified as a suitable marker for diesel particulate emissions (< 5um). A large volume air sample from Sheffield city centre using 1-nitropyrene as a marker suggested that 63% of atmospheric particulate material (< 5um) might be of diesel origin. However the concentration of 1-nitropyrene is low in atmospheric samples, and in the volumes used in routine sampling the amount of 1-nitropyrene was below the limit of detection on the instrument used. In an alternative approach the aliphatic alkane tetracosane (C24) was used as a diesel marker for urban air, with a 1-nitropyrene:tetracosane ratio derived from the average results from laboratory experiments with a diesel engine running at various speeds and loads. This approach yielded apportionment values ranging from 5-85% for the diesel contribution to particulate material (< 5mum) in the urban air of Sheffield. No volatile marker compound was found for diesel apportionment. The contribution of ETS to atmospheric pollution has previously been estimated from the measurement of respirable suspended particulates (RSP), which was superseded by total UV absorbance and total fluorescence of a methanol extract. More recent work has suggested the use of solanesol or scopoletin as marker compounds. This thesis shows that the non specific methods overestimated the particulate contribution of ETS in some atmospheres, and that solanesol is a better marker compound than scopoletin. Preliminary studies from a small number of smokers homes and offices, with solanesol as a marker compound for particulate ETS, indicated that ETS contributions to total particulate material (< 5mum) ranged from 6 to 49% in homes and 11 to 28% in offices. Pyrrole was used as a marker for ETS contribution to volatile organic pollution, and studies with controlled atmospheres with a smoking machine allowed calculation of the ratios of pyrrole to other volatile organic compounds (VOC's) in ETS. Samples from the field study were used to produce apportionment percentage levels of benzene, toluene, o-xylene and p+m-xylene associated with ETS.In addition the use of tree bark as a atmospheric sink for airborne particulates was investigated. Six nitrated polycyclic aromatic hydrocarbons associated with diesel emissions were quantified in bark extracts and levels of these were found to be highest during winter months.

As part of the Avon Longitudinal Study of Pregnancy And Childhood, the toxic metal, mercury, is studied in order to assess whether it presents a danger to the development of children in the UK.The development and optimisation of a digestion procedure for the determination of total mercury in hair is described. The procedure chosen consists of the microwave digestion of 0.2-0.5g hair with 2 ml HNO3 and 1 ml H2O2 . The effect of washing and drying of the samples is investigated, and found not to influence analytical results when hair samples are collected after shampooing. However, freeze-drying of the samples results in the loss of 30% of mercury. The distribution of mercury along the length of a strand of hair is studied. It is shown to vary in adults (up to a factor of 7) but not in children (less than 20%). In the applications of this analytical method to population studies, the frequency of fish meals, and the age of the subject are positively correlated to the mercury levels in adults' hair (r = 0.539 and 0.513, respectively). Breast-feeding and mercury levels in children's hair are also correlated (r = 0.433). The relationship between number of fillings and mercury levels in adults' hair is not significant. No correlation was found between mercury levels in children's hair and Developmental Quotient (Griffith's scales) (r = -0.24 to 0.18).The optimisation of a coupled High Performance Liquid Chromatography - CV-AFS system for the study of mercury speciation is described. The use of KOH and microwave digestion for the extraction of mercury species was unsuccessful, and thus recommendations for future work are made.

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Swirl burners are widely used in industry. Recent environmental concerns, particularly on emissions from combustion processes, have introduced the requirement to modify these processes to reduce emissions whilst at the same time maintaining combustion efficiency. This thesis presents details of experimental and computational studies into the flowfield structures of swirl burners. Previous investigators have concentrated on the time-average flows, but it has become apparent that these are insufficient to enable pollutant emissions to be accurately predicted. Knowledge of the time-temperature and species history is needed to obtain better predictions. Pivotal to this is a detailed determination of the time-dependent structure of the flow. In this study, series of experiments were carried out at different inlet configurations and conditions. The flowrate and swirl number were varied as well as the injection mode, inlet length and exit geometry. The burner flow was characterised by measuring axial, tangential and radial velocities using a Laser Doppler Anemometer. A Computational Fluid Dynamics modelling package, FLUENT was used to produce two and three-dimensional computational models to predict the flowfield structures of the burners in isothermal and combustion cases. Four turbulence models were evaluated in the prediction: the k-e Model, the Algebraic Stress Model (ASM), the Reynolds Stress Model (RSM) and the Re-normalisation Group Model (RNG). Constant velocity scaling of the 100 and 500 kW burner was examined in both experimental and computational studies. The experimental results show that the flowfield structures in both burners are nonaxisymmetric and develop three-dimensional time-dependent coherent structures in the flow. The experimental results have been compared with the computational model predictions. The comparisons reveal very good agreement between the time average measurement and the predictive values, especially downstream of the burner exit. This work was extended to investigate the following novel phenomena: a). The computational prediction of the flowfield structure was extended to include different inlet boundary conditions with both the RSM and the RNG turbulence models. The model was also extended to investigate the time-dependent flows. b). The influence of varying the inlet and exit geometries and conditions on the flow patterns and the reverse flow zone was examined in detail. A 500 kW swirl burner with scroll inlet was designed and characterized with time-dependent flows to simulate the Precessing Vortex Core. This investigation showed very good agreement with experimental velocity data with less constrained boundary conditions that had previously obtained. The time-dependent simulation was limited by the computer speed and processing capability but identified that such analysis is possible when computer power allows and has the potential to model the flow in greater detail yielding more accurate data on pollution emissions.

This thesis describes the evaluation of the first commercially available Hewlett Packard gas chromatograph - microwave induced plasma - atomic emission detector (GC-MIP-AED) for application to qualitative and quantitative analysis. The technique was applied to a range of environmentally significant samples. A general introduction to the development of the technique and its suitability for environmental applications is discussed and a number of typical applications are reviewed. A fundamental study of the capabilities of the GC-MIP-AED was undertaken. It became apparent that the manufacturers pre-programmed recipes for the different elemental channels required optimising to eliminate ghost emission signals from other sources such as carbon molecular emission. After the optimisation of these elemental recipes for C, S, N, O, Pb and Cl had been achieved the ability of the instrument to perform multielement heteroatom profiling of a range of pollutants with a high degree of selectivity was established. Samples included oils, leaded and unleaded petrols, and coal pyrolyzates. A critical assessment of the instruments capabilities with respect to these applications and other operational issues is also described. The instruments ability to perform quantitative analysis was then studied highlighting a number of problem areas, such as, variable repeatability and limits of detection, relating to the automatic injection facilities. When the appropriate injection liner and injection technique were used, the limit of detection on all the elemental channels monitored was greatly improved. The study was then extended to utilise the GC-MIP-AED for the multielemental analysis of organomercury, organolead and organotin compounds. The instrumental conditions were optimised for each element individually with respect to instrumental operating parameters, repeatability, limit of detection, linearity of response, and also the chosen extraction and derivatisation technique. All parameters were then optimised for the analysis of organomercury, organolead and organotin compounds within a single chromatographic injection for environmental applications including sediment, fish tissue and water samples. The overall objective of this thesis was to identify and evaluate the multielement capabilities of the analytical technique for qualitative and quantitative application to samples of environmental relevance, in particular simultaneous multielement organometallic speciation.

This thesis describes an investigation into the effect of piston design on hydrocarbon emissions from an spark ignited engine. The experimental investigation tested a series of three piston configurations against a standard design based on production dimensions. These tests examined the effect of top and 2nd land crevice volumes and absorption and desorption from lubricant on the cylinder liner as sources of hydrocarbon emissions. The operational conditions were steady state for all engine parameters. The work was performed on a modern four cylinder 16 valve engine with multi point fuel injection. Two fuels were used, a reference unleaded petrol and trimethyle pentane. The results have shown that significant reductions in hydrocarbon emissions can be achieved by certain design changes. Reducing the top land height from 6mm to 2.8mm reduced emissions by up to 25% and creating a smoother surface on the cylinder liner wall reduced emissions by up to 28%. A method of assessing residual lubricant on the cylinder walls was developed from surface finish measurement and showed that the smoother surface finish would retain less oil and reduce the amount of fuel absorbed by the oil. The 2nd land volume was a secondary source having an effect at low speed low load conditions. The hydrocarbon species were investigated with gas chromatography, the concentrations of these species were observed to change with each design, but not necessarily proportional to the total hydrocarbon emissions. A model was developed to allow the prediction of changes to hydrocarbon emissions by altering various piston design parameters. In addition to modelling mixture flow into piston crevice volumes and absorption of fuel by lubricant on cylinder walls a basic combustion analysis allowed the prediction of combustion gas temperatures and the end point of combustion. In-cylinder oxidation could then be approximated. Results from this model gave good agreement with experimental results and was then used to assess the optimum piston design to reduce hydrocarbon emissions. This research has demonstrated that component design and specification can be used to reduce hydrocarbon emissions from a spark ignited engine. The most significant parameters have been identified and methods of measurement developed. After considering current material and design constraints the dimensions for a low hydrocarbon emission piston was modelled and predicted 30% reduction in emissions.

Diesel Particulate Matter (DPM) and coal dust samples were characterised using Raman microscopy, X-ray Photoelectron Spectroscopy (XPS), Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Thermo-Gravimetric Analysis (TGA), X-ray Fluorescence (XRF) spectrometry and Scanning electron Microscopy. The sp2/sp3 carbon bonding ratios for DPM and coal dust were determined as 6.1 and 0.7, respectively, from XPS. Principal Component Analysis (PCA) was successfully implemented as a tool for distinguishing between the very similar DPM and coal dust Raman spectra, with over 99% of the variance contained in the first principal component. DPM and coal dust mixtures with known compositions were produced. Raman instrumental parameters were systematically optimised by varying the objective lenses, acquisition times and laser powers, to improve spectral and obtain the most reproducible integrated spectral areas. A rotation stage was developed and employed to spin the specimens during analysis, resulting in a larger sampling area. This resulted in a more representative sampling regime for the heterogeneous specimens and a considerable improvement in the reproducibility of integrated spectral areas. The error in the integrated spectral areas of 10 replicate spectra of different mixtures ranged from 5-22% before implementation of the rotating stage and was notably reduced to 2 -6% due to the action of spinning. Raman spectra of mixtures were used to construct a Partial Least Squares (PLS) model. The R2 values for the DPM and coal dust were 0.865 and 0.763, respectively. The differential bum-off of volatile organics during the Raman analysis due to localised heating from the laser hindered the ability to gain highly reproducible spectra and thus markedly affected the PLS model. A method development stage aimed at improving the R2 values was applied to the samples. This involved heat-treating the specimens to 625°C in an inert nitrogen atmosphere, before the Raman analysis. The resultant PLS model, after heat-treatment, dramatically improved the R2 values such that the DPM and coal dust were 0.974 and 0.907, respectively. This model was used to predict the composition of a test sample with known amounts of DPM and coal dust. The concentrations predicted by the model were 166 ± 3.9pg for the DPM and 68 ± 7.8jxg for the coal dust. The model slightly overestimated the amount of DPM present in the sample but gave a large underestimation of the coal dust content. The diagnostics of the model were investigated and recommendations for the improvement of future models were given.