Dissertations / Theses on the topic 'Wood-burning'

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Esta dissertação analisa algumas transformações morfológicas em equipamentos de cozinha, referentes à conservação e preparo de alimentos, nas moradias da classe média carioca, entre as décadas de 30 e 60. Para realizar esta análise, a autora considera o contexto social, econômico, político e cultural e verifica suas influências na transformação da forma. Através de uma perspectiva histórica, pontua os fatos mais relevantes na formação do corpo social brasileiro da época,destacando a sociedade urbana do Rio de Janeiro, assim como as transformações sofridas por essa sociedade. Focaliza as dimensões culturais, dando maior destaque à cultura material. Observa as influências internacionais e as conseqüências dessas influências na configuração dos equipamentos fabricados no Brasil. Através de anúncios publicitários da época, fotografias, manuais de utilização e da descrição realizada por alguns teóricos, a autora verifica e interpreta as transformações, e as relaciona com o contexto em que se realizaram.
This dissertation analyses some morphologicaltransformations in kitchen equipment which was used for conserving and preparing food in middle class homes in Rio de Ja-neiro between the decades of the 1930 s and 60 s. To do this analysis, the author considered the social, economic, political and cultural con-texts and verified these influences on the types of transformations ob-served. From a historical perspec-tive, the most relevant factors con-tributing to the makeup of Brazilian society at the time are pointed out, with emphasis on urban society in Rio de Janeiro and the changes this group underwent. The focus is on cultural factors, mostly emphasizing the culture of material items. Inter-national influences and their conse-quences on the characteristics of equipment produced in Brazil are observed. By way of advertisement from the time, photographs, user manuals and the descriptions made by some theoriticians, the author verifies and interprets the transfor-mations and their relationship to the context in which they were made.

The Earth’s atmosphere consists of both gaseous and condensed-phase components, the condensed-phase material is called particulate matter (PM). The effects of atmospheric PM include adverse health impacts, as well as climate forcing. Both qualitative and quantitative knowledge about PM is necessary to assess these effects, and to devise best mitigation strategies. Understanding the distribution of atmospheric particulate matter is complex because much of it is of secondary origin rather than from primary emissions. Furthermore, there are multiple anthropogenic and natural sources of the contributing precursors, and all these processes are influenced by atmospheric conditions and transport. In this work, one of the major constituents of atmospheric PM - carbonaceous aerosol - is studied. A regional application of the EMEP MSC-W atmospheric chemical transport model - EMEP4UK - was used to model air pollution over the British Isles with a horizontal resolution of 5 km x 5 km. One-way nesting was used from the European computational domain of 50 km x 50 km to the finer spatial grid of EMEP4UK. Several model experiments were devised in order to investigate the well-known deficiency that models currently underestimate organic aerosol (OA) concentrations compared with observations. The model experiments were evaluated with comprehensive year-long novel measurements from the Clear Air for London (ClearfLo) campaign in 2012. Several sources of organic aerosol that are either missing, greatly underestimated, or may be spatially misplaced in official emissions inventories were re-evaluated. Firstly, missing diesel-related intermediate volatility organic compound (IVOC) emissions from diesel vehicles derived directly from field measurements at the urban background site during the 2012 ClearfLo campaign were added into the model. According to the model simulations, these diesel-IVOCs can explain on average ~30% of the annual secondary organic aerosol (SOA) in and around London. Furthermore, the 90- th percentile of modelled daily SOA concentrations for the whole year was 3.8 μgm-3, constituting a notable addition to total particulate matter. More measurements of these precursors (currently not included in official emissions inventories) is recommended. Secondly, spatially and temporally resolved emissions of cooking OA (COA; emissions from meat charbroiling, or frying and deep-frying) were developed. These emissions are currently neglected in European emissions inventories, yet measurements point to significant COA contribution to ambient PM concentrations (up to 2.0 μgm-3 on annual average for central London). The final COA emission source strength derived here (320 mg person-1 day-1) was spatially distributed to workday population density (as opposed to residential population density). The impact of COA on surface concentrations is spatially very limited, however, as the modelled concentrations dropped markedly outside of urban areas. For example, annual average modelled concentration for the Harwell location was just 0.1 μgm-3. Thirdly, redistributing 50% of non-industrial wood and coal burning emissions to residential population density (thus over-writing, in part, the assumption made by the national emissions inventory that only smokeless fuels are burned in smoke control areas) increased the modelled solid fuel OA (SFOA) concentration at the London North Kensington site to 0.8 μgm-3, from the Base run value (using the emissions’ spatial distribution and total as officially reported) of just 0.3 μgm-3. For comparison, the measured annual mean concentration of SFOA at this site was 1.0 μgm-3. Based on the model evaluation presented, redistribution of SFOA emissions into smoke control areas is justified, but further refinement of the amount, as well as the temporal emission profile of this component is necessary. The total effect of the three refinements undertaken in this work increased the model estimate of the annual mean OA concentration at the London North Kensington site from 1.8 μgm-3 to 3.8 μgm-3, which is much closer to the observed value of 4.2 μgm-3. Thus, this work has provided relevant insight into the nature and magnitude of missing, under-represented, and spatially inappropriately-distributed emissions of primary OA and OA precursors. Although the study area was focused on pollutant concentrations over the British Isles, all of the components examined here are of great relevance to the air quality in other countries as well — in Europe and globally. Therefore, the inclusion of these improvements into other air quality models and official emissions’ inventories is advised.

Les émissions de matière particulaire fine (MP2.5) provenant des poêles à bois résidentiels sont une source majeure de pollution atmosphérique en Amérique du nord et en Europe du nord en hiver. Cette pollution a été liée à de nombreux problèmes de santé respiratoires. Nous pouvons réduire ces émissions par l’utilisation d’un précipitateur électrostatique (PES) à la sortie du tuyau d’échappement des gaz de combustion. Cette étude avait comme hypothèse qu’un tel dispositif pouvait opérer de façon efficace et ainsi contribuer à une réduction substantielle des émissions de particules fines provenant du secteur de chauffage au bois résidentiel. Un modèle numérique en 2-D d’un PES a été crée et simulé avec un logiciel commercial de mécanique des fluides numériques. Le modèle et le procédé comportaient plusieurs améliorations par rapport aux modèles trouvés dans la littérature, dont : l’utilisation d’une distribution de particules polydispersées, l’utilisation d’un écoulement semi-établi à l’admission des gaz et l’utilisation d’un modèle de chargement des particules qui tient compte des chargements par diffusion et par champs. La technique a été validée par des données expérimentales, et les valeurs de rendement correspondaient avec moins de 5% d’écart aux valeurs expérimentales. Un modèle de référence basé sur les dimensions d’un tuyau d’échappement standard de 0,15 m de diamètre a été simulé et le rendement global était de 75%. L’utilisation répandue de ce dispositif pourrait mener à une réduction de 64% des émissions de MP2.5 provenant du secteur de chauffage au bois résidentiel au Québec. Il y a plusieurs défis opérationnels et de sécurité qui doivent être surmontés avant de pouvoir commercialiser un tel dispositif.

PM2.5 variability within the neighborhood scale has not been thoroughly studied for wood burning communities. High variability in near-field PM2.5 concentration may lead to harmful public exposure since monitoring does not occur on that scale. This study measures near-field PM2.5 variability by measuring black carbon (BC), a component of PM2.5, in a 1 km2 area located in Cambria, California. BC and meteorological data (when meteorological instruments were available) were measured over thirteen 12-hour intensive operation periods (IOPs) occurring over the winters of 2009 and 2010. Near-field BC variability was measured to understand the type of exposures found in communities where many homes are burning wood simultaneously within a small area. In addition, relationships between meteorological, geographical, and burning source characteristics and BC were observed as tools for understanding BC concentration. The computer air dispersion modeling programs, ISC-PRIME and ISCST3, were also evaluated for applicability to the near field. BC concentrations were measured using 1- to 2-minute resolution aethalometers and 12 hour resolution Personal Environmental Monitors (PEMs). On average, over all IOPs and sites, aethalometer and PEM BC averages were very similar, ranging between 200 and 250 ng/m3, or 4 and 5 µg/m3 for PM2.5, and standard deviations were often high. Averaging all BC measurements, aethalometer BC standard deviation values were 360 percent of the average BC concentration and PEM BC standard deviations were 120 percent the average BC concentration. The average standard deviation detected during each IOP was 190 percent of the average BC concentration for aethalometers and 79 percent of the average BC concentration for PEMs. The average standard deviation detected at each site was 220 percent of the average BC concentration for aethalometers and 76 percent of the average BC concentration for PEMs. The larger standard deviations measured by higher resolution aethalometers demonstrated that low resolution instruments, such as PEMs, are unable to detect high concentrations that may occur. In addition to examining BC variability, multiple linear regression analyses were conducted to determine the impact of meteorological variables and geographic and burning source characteristics on BC concentration and a weighted BC deviation function (BC standard deviation divided by average BC concentration). Time impacts, humidity, and wind speed, accounted for about 50 percent of variability in aethalometer average BC and BC deviation. However, because all model assumptions were not satisfied, improvements are needed. Regression models based on PEM BC found wind speed and direction to account for about 80 percent of average PEM BC variability and number of burning sources to account for about 30 percent of PEM BC deviation. Although PEM BC models accounted for a high percentage of BC variability, few data points were available for the PEM analyses and more IOPs are needed to determine their accuracy. When evaluating correlations between geographic and burning source characteristics and PEM BC concentrations, specific IOP and PEM sampling location explained almost 70 percent of variability in BC concentration, though model residuals suggested model bias. IOP likely explained variation in burning patterns and meteorology over each night while sampling location was likely a proxy for housing density, tree coverage, and/or elevation. Because all regression model assumptions could not be satisfied, the predictors were also observed graphically. Plotting BC concentration versus the number of burning sources suggested that number of burning sources may affect BC concentration in areas of low tree coverage and high housing density and in the case that the level of surrounding vegetation and structures are minimal. More data points will be needed to determine whether or not these relationships are significant. ISC-PRIME and ISCST3 modeling overall tended to under predict BC concentrations with average modeled-to-measured ratios averaging 0.25 and 0.15, for ISC-PRIME and ISCST3, respectively. Correction factors of 9.75 and 18.2 for ISC-PRIME and ISCST3, respectively, were determined to bring modeled BC concentrations closer to unity, but the range of ratios was still high. Both programs were unable to consistently capture BC variability in the area and more investigation will be needed to improve models. The results of the study indicate high BC variability exists on the near-field scale, but that the variability is not clearly explained by existing regression and air dispersion models. To prevent public exposure to harmful concentrations, more investigation will be needed to determine factors that largely influence pollutant variability on the neighborhood scale.

Improved cooking stoves can bring significant benefits to women and children in rural African situations, due to reduced fuel consumption and improved indoor air quality. This investigation focuses on the use of Computational Fluid Dynamics (CFD) and Genetic Algorithms (GAs) to optimise a stove for Eritrea. Initial work focussed on developing a model of wood combustion in a fixed bed. An experimental investigation was carried out on regular wood cribs to determine the burn rate and temperature field above a wood fire. The experimental data was used to develop a numerical model using CFD software Fluent 6.2 and user-defined functions for the fixed bed of fuel. The model assumed that pyrolysis was limited by heat transfer through the fuel, and that char combustion was limited by oxygen diffusion to the fuel surface. Simulation results yielded a mean and maximum error of 16% and 42% respectively in fuel burn rate. In the second phase of the investigation, the numerical model of wood combustion was used as part of a larger CFD model to capture the behaviour of a complete stove. The model was compared with experimental data for rocket type stoves with different geometries. The model correctly identified the trends of fuel burn rate and heat transfer in the experimental data, though agreement with experimental values was poor and the model exhibited significant errors when altering stove height and diameter. In the final phase of the investigation, the stove model was used in conjunction with a genetic algorithm to optimise the stove shape. Two methods of genetic coding were investigated. The resulting stove is expected to half fuel consumption compared to the classic mogogo stove, though this remains to be experimentally verified.

During the last 10 years, air pollution has become one of the major public health problems in Ulaanbaatar city of Mongolia, and concentrations of pollutants were measured 3 to 50 times higher than WHO recommendation. This devastating air pollution is produced mostly by thousands of families who migrated from countryside and live in gers (traditional dwellings) in the suburban area which is not connected to the central heating system, and nearly all of them burn coal to keep them warm. Due to air pollution, residents living in Ulaanbaatar city suffer health problems that equal to the smoking of 4-5 packs of cigarettes. During the winter time, PM10 hourly average concentrations increased to 2,300 μg/m3, and daily average became over than 1,000 μg/m3 in the most polluted parts of the city. At present, Mongolian government has accepted that the health of Mongolian residents has deteriorated at an alarming level. In January of 2011, Mongolian Parliament approved the Law on Reduction of Air Pollution in the Capital City to control air pollution and eliminate the gaps in practice. One main provision of this law was to improve ger district electricity transmission and distribution network and reduce the night-time price of electricity by 50 percent. Therefore, this study aimed to estimate direct health benefits of Government Provision on cutting electricity payment by 50 percent during the night time and analyze the efficiency of this program on reducing air pollution and its related health impact. The study result showed when this new regulation is fully implemented in the ger districts, the annual consumption of coal and wood would be decreased by about 550,000 tons and 415,000 tons, accompanied by massive reduction of the emission. These changes would lead into noteworthy health benefits such as 15.7 and 17.4 percent of reduction of total and infant mortality rates and 4.3 and 4.7 percent decrease of cardiovascular and respiratory disease morbidity cases, annually.

Tyrimo tikslas – ištirti medienos džiovyklos, kūrenamos biokuru, energijos sąnaudas ir energinį efektyvumą. Tyrimo uždaviniai – išanalizuoti biokuro katilinės technologinį procesą, nustatyti biokuro charakteristikas ir biokuro poreikius medienos džiovinimui, sudaryti džiovinamos medienos elektros ir šiluminės energijos sąnaudų skaičiavimo metodiką. Eksperimentinio tyrimo metu nustatytas biokuro (pjuvenų) šilumingumas (9,3 MJ/kg) ir jo drėgnis (47,0 %). Nustatytos katilinės elektros įrenginių ir medienos džiovyklos suminės energijos sąnaudos, kurios siekia 686 MJ/m3 išdžiūvusios medienos.
The aim – to investigate wood drying, burning biofuels, energy consumption and energy efficiency. Objectives of the study – to analyse the biofuel boiler process that determine the characteristics of biofuels and biofuel needs of timber drying, consist of dried wood of electrical and thermal energy cost calculation methodology. Results of experimental investigation shows that calorific value of biofuel (saw dust) is 9,3 MJ/kg and humidity – 47,0 %. The total energy consumption of electrical installations and wood drying machine has been determined, which shows the total energy input of 686 MJ/m3 dried wood.

À une époque où les conditions matérielles de l’existence différaient profondément de celles qui sont aujourd’hui les nôtres, quel était l’impact des variations saisonnières de températures sur les individus et sur la société ? Comment les hommes et les femmes du passé enduraient-ils le froid de l’hiver et tentaient-ils de s’en préserver ? Quelle était l’efficience des moyens mis en œuvre pour lutter contre le froid et quelles pouvaient être les températures qui régnaient l’hiver à l’intérieur des habitations ? À la suite des intuitions pionnières de Lucien Febvre ou de Robert Mandrou, ce travail, à la croisée de l’histoire du corps et de celle des sensibilités, tente de de retracer la généalogie de notre rapport sensible au monde. La première partie de la thèse, après avoir évoqué les apports et les limites des différents types de sources dépouillées, est consacrée à étudier la manière dont les fluctuations de températures sont perçues, notées et pensées à des époques où le froid et la chaleur sont davantage des expériences sensibles que des grandeurs physiques mesurables. On y étudie aussi la manière dont les vagues de froid impactent, plus qu’aujourd’hui, la vie quotidienne et posent aux individus et à la société d’insolubles difficultés. En s’interrogeant sur la figure récurrente du “grand hiver”, on en vient à montrer que ces descriptions d’hivers rigoureux révèlent tout autant une réalité climatique objective qu’une extrême vulnérabilité des sociétés anciennes face au froid. La seconde partie centrée autour de la question de la civilisation matérielle tente de retracer les différentes stratégies mises en œuvre pour lutter contre les assauts de l’hiver. On y étudie ainsi la place et le rôle de la cheminée dans l’habitation ainsi que la manière dont elle constitue un trait de civilisation qui conditionne des manières d’habiter et des attitudes corporelles qui n’échappent pas au processus de civilisation. Les médiocres performances calorifiques de la cheminée expliquent le recours nécessaire à des sources de chaleur portatives et la mise en place de multiples stratégies de lutte contre le froid qui varient en fonction des régions et des milieux sociaux. La France préindustrielle apparaît ainsi comme un monde de l’économie permanente et de la chaleur rare où le souci constant de l’économie du combustible explique la cohabitation recherchée avec les bêtes, l’entassement des corps dénoncés par les médecins des Lumières et l’existence de certaines formes de sociabilité. En essayant de reconstituer la cohérence d’un système et d’habitus aujourd’hui disparus, on est naturellement amené, dans une troisième partie, à poser la question de la sensibilité — au sens physiologique mais aussi social du terme — au froid et à la chaleur ainsi que celle de son évolution. Dans un essai d’archéologie du corps, on tente de reconstituer les climats intérieurs des habitations d’autrefois en s’efforçant de déterminer les températures de confort. L’accoutumance à des températures intérieures relativement basses au regard de nos exigences actuelles amène à souligner le caractère socialement et culturellement construit des seuils de tolérance et à interroger le rapport à l’inconfort et à la douleur puisque le froid, s’il est enduré, n’en provoque pas moins souffrances et lésions corporelles. En étudiant les cheminements sinueux de la réflexion technique relative à la question du chauffage qui se développe au cours du XVIIIe siècle, on est aussi amené à s’interroger sur les interactions complexes entre la société, les évolutions scientifiques et technologiques et l’évolution des seuils de tolérance individuels et sociaux au froid et à la chaleur. Le XVIIIe siècle apparaît ainsi comme un siècle charnière où s’exprime pour la première fois ouvertement une demande sociale de chaleur (condamnée par les moralistes et les médecins) qui préfigure notre besoin insatiable de confort
At the time when material conditions in our existence deeply differed from those we know nowadays, what was the impact of the change in the seasonal temperatures on the individuals and society? How did the men and women of the past endured winter cold and how did they strive to protect themselves from it? How efficient were the means used to fight the cold and what could the indoor temperatures be in winter? After the first intuitions sensed by Lucien Febvre and Robert Mandrou, this work, at the crossroads of the history of the body and that of sensitivity, tries to trace out the genealogy of our sensitive relation to the world. After mentioning the contributions and the limits found in various types of studied sources, the first part of this dissertation is devoted to the way the change in temperatures were perceived, noted or thought at a time when cold and heat were more perceptible experiences than measurable physical quantities. It also deals with the way the cold spells affected daily life and that more than today troubled both the individuals and society with unsolvable difficulties. Wondering about the recurring figure of the “great winter”, it shows that those descriptions of harsh winters revealed a climatic reality as much as the old societies’ extreme vulnerability to the cold. The second part revolving around the question of the material civilization tries to recount the different strategies used to fight the onslaught of winter weather. Thus it studies the role and importance of fire places in homes as well as the way it brought a feature of civilization which changed both the living conditions and the physical attitudes that were implied in the process of civilization. The poor calorific value of fire places explained the necessary resort to mobile heating sources and the establishment of numerous strategies to fight the cold, which changed according to the regions and the social standing. Thus, Preindustrial France was understood as a world of permanent economy and of scarce heat where the constant question of the combustible material economy could explain the importance of living with cattle, of overcrowded places - denounced by the doctors in the Age of Enlightenment - and the existence of certain forms of social skills. Trying to recreate the coherence of a system and habitus that have disappeared today, a third part naturally raises the question of sensitivity – in the physiological but also social meaning of the term – to cold and heat and its evolutions. In an essay on the archeology of the body, we tried to recreate the conditions inside the dwellings of the past, in an effort to determine the comfort temperature. The compliance with relatively low indoor temperatures regarding our current demands led us to underline that our capacity to acceptance had been culturally and socially built up and to question our relation to discomfort and pain since the cold, even though it was supported, entailed suffering and physical damage. Pondering over the technical reflection to the heating issue that had developed throughout the 18th century, we were led to go over the complexity of the interaction between society, scientific and technologic evolution and the individual and social acceptance to the cold and heat. The 18th century seemed to be the turning point where for the first time a social demand for heat had been overtly expressed (though condemned by both moralists and doctors) which heralded our unquenchable need for comfort. The expression for that social demand did not necessarily mean that it would be universally satisfied. Consequently, the old thermal regime would be lasting beyond this studied period…

La pollution atmosphérique résulte d’un mélange complexe de composés, des gaz et des particules, dont les effets sont notoirement néfastes. Les composés organiques volatils (COV) tiennent un rôle prépondérant dans la chimie atmosphérique et sont précurseurs d’ozone et d’aérosols organiques secondaires (AOS). En Île-de-France, l’exposition à la pollution est préoccupante ; or, des incertitudes significatives sont toujours associées aux sources de polluants, ainsi qu’à leur intensité et leurs variabilités à différentes échelles de temps et très peu d’investigations ont porté sur la quantification de l’exposition individuelle. Dans ce contexte, cette thèse a cherché à mieux caractériser les variabilités temporelle et spatiale de la pollution en Île-de-France.La fiabilité discutable des capteurs portables a été dépassée par l’élaboration d’un protocole de sélection et de qualification comprenant différents tests en mesures fixes, en chambre et en mobilité. Cette nouvelle méthodologie, basée notamment sur l’utilisation d’un outil combinant différents indicateurs statistiques, a été appliquée pour retenir l’AE51, le Cairclip et le Canarin, mesurant respectivement le carbone suie (BC), le dioxyde d’azote (NO2) et les particules (PM).Ces trois capteurs ont été déployés au cours de campagnes de mesures impliquant une trentaine de volontaires. L’exposition individuelle ainsi quantifiée est plus élevée à l’automne qu’au printemps et varie de manière substantielle en fonction des différents environnements fréquentés. La proximité de la circulation routière (pour le BC et le NO2) ainsi que les activités de cuisine et la fumée de tabac (pour les PM) présentent des contributions importantes à l’exposition totale (jusqu’à 34 %, 26 % et 44 % respectivement), alors même que le temps passé dans ces environnements est faible.En plus du trafic routier, le BC est traditionnellement imputé au feu de bois. Une campagne hivernale de mesures (3,5 mois) a permis d’imputer respectivement 22 % et 47 % des COV mesurés à ces deux sources. Certains composés ont été mesurés et associés au feu de bois pour la première fois en air ambiant comme le benzènediol et le méthylbutènone. Une comparaison avec l’inventaire régional des émissions a permis d’identifier des similitudes et des différences pour proposer des améliorations
Air pollution results from a complex mixture of compounds, gases and particulate matter, whose effects have proven to be harmful. Volatile organic compounds (VOCs) play a major role in atmospheric chemistry and are precursors of ozone and secondary organic aerosols (SOAs). In Île-de-France, exposure to pollution is a concern; however, significant uncertainties are still associated with the pollutants’ sources, as well as their intensity and variability at different time scales, and very few investigations have focused on quantifying personal exposure. In this context, this research sought to better characterize the temporal and spatial variabilities of pollution in Île-de-France.The questionable reliability of portable sensors has been addressed by the design of a selection and qualification protocol including various tests in static measurements, controlled chamber and mobility. This new methodology, based in particular on the use of a tool combining different statistical indicators, was applied to choose the AE51, Cairclip and Canarin, measuring black carbon (BC), nitrogen dioxide (NO2) and particulate matter (PM) respectively.These three sensors were deployed during measurement campaigns involving about thirty volunteers. The personal exposure thus quantified is higher in fall than in spring and varies substantially according to the different environments frequented. Proximity to road traffic (for BC and NO2) as well as cooking activities and tobacco smoke (for PM) make significant contributions to total exposure (up to 34 %, 26 % and 44 % respectively), even though the time spent in these environments is short.In addition to road traffic, BC is traditionally attributed to wood burning. A winter measurement campaign (3.5 months) attributed respectively 22 % and 47 % of the measured VOCs to these two sources. Compounds including benzenediol and methylbuteone were measured and associated with wood burning for the first time in ambient air. A comparison with the regional emissions inventory identified similarities as well as differences and suggested improvements

This study concentrates on indoor air pollution, specifically particulate matter, as a result of woodburning in the home. Three single-family residences in Richmond, Indiana, equipped with identical airtight woodburning stoves and using a controlled wood supply, were monitored for a 49-day period in 1987. Particluate matter samples were collected during periods of active wood combustion and periods absent of wood combustion using low-volume samplers. Significant differences were found in two of the three houses when wood combustion and non-wood combustion periods were compared. No relationship was found between particle levels and time of day, ambient air temperature, pounds of wood burned, refueling duration or refueling frequency. It was concluded that woodburning can affect the quality of indoor air in particulate matter levels.
Department of Natural Resources

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: A lab scale combustion unit was designed, in order to characterise the performance of various woody and wood-based biofuels commonly used for energy production, cooking and heating. The unit was constructed in a way that it could be repeatedly reused and provide similar testing conditions, such as airflow for all samples. The requirements were that it was big enough to contain a fire large enough to yield good time/temperature profiles and at the same time easy to handle, operate and clean. It also had to allow the insertion of the thermocouples and flue gas probe. Time / temperature profiles were obtained and O2, CO2 and CO levels in the flue gas determined for each biofuel. The samples consisted of the five most commonly used fuel wood species in the Western Cape, namely Rooikrans, Camelthorn, Bluegum, Black wattle and vine stumps and five processed products, namely wood pellets, wood briquettes, commercial charcoal, commercial briquettes and handmade briquettes. Combustion time/temperature profiles were obtained for all samples and characteristic values, such as the maximum temperature and coal temperature compared. This allowed an indication of which product performed better than others in the different combustion phases and is more suitable for different requirements, such as industrial heating, or domestic cooking. Even though Bluegum and Camelthorn performed best overall they were not necessarily suited, for example, for large scale industrial use. It was found that wood pellets and charcoal were the best biofuel for industrial purposes, whereas Rooikrans was found to be the best option for small scale use.
AFRIKAANSE OPSOMMING: ‘n Laboratoriumskaal verbrandingseenheid was ontwerp vir die toets en karakterisering van verskeie houtgebaseerde biomassa soorte algemeen in gebruik vir energie opwekking, kook en verhitting. Daar was besluit om ‘n eenheid te bou vir herhaalde gebruik wat die omstandinghede vir elke toets konstant kan hou, bv. ‘n damper om lugvloei deur die sisteem the beheer. Die eenheid moet groot genoeg wees om veilig ‘n groot genoeg vuur the bevat waarmee ‘n goeie tyd/temperatuur profiel verkry kan word, maar terselfdetyd klein genoeg wees om te hanteer, operateer en skoon te maak. Die eenheid moes ook voorsiening maak vir die insteek van die termostate en gas peilstif. Tyd/temperatuur profiele is verkry en O2, CO2 en CO vlakke in die uitlaatgas is bepaal vir elke bio-brandstof. Die monsters was saamgestel uit vyf van die mees algemeen gebruikte brandhout spesies in die Wes Kaap, naamlik Rooikrans, Kameeldoring, Bloekom, Swartwattel en wingerdstompies, asook vyf geprosesseerde produkte naamlik houtpille, houtbrikette, kommersiële steenkool, kommersiële brikette and handgemaakte brikette. Verbranding tyd/temperatuur profiele is verkry vir al die monsters en verteenwoord waardes is daarvan afgelees, bv. die maksimum temperatuur wat bereik is of die temperatuur waar die vlamme uitgesterf het en slegs koolhitte gemeet word. Hierdie profiele het dit moontlik gemaak om te identifiseer watter produk het beter gevaar as ander gedurende die verskillende verbrandingsfases en is beter gepas vir verskillende gebruike, bv. huishoudelike kook en verhitting. Resultate het gedui dat die Bloekom en Kameeldoring die beste gevaar het oor all die toetse heen, maar was nie noodwendig ideaal vir elke spesifieke doel nie. Dit was bevind dat die steenkool en houtpille die beste gepas is vir industriele gebruik en dat die Rooikrans beter geskik is vir huishoudelike en kleinskaalse gebruik.

La combustion de la biomasse, en particulier le chauffage au bois résidentiel, constitue une source d’émissions fortement contributrice aux concentrations de PM10 en hiver, de façon globale, en Europe. Afin de réduire les émissions de cette source, un programme de large envergure de renouvellement d’appareils de chauffage au bois non-performant, le Fonds Air Bois a été lancé depuis 2013 dans la vallée de l’Arve. Cette action étant amenée à se multiplier en France, l’évaluation de son effet sur les concentrations atmosphériques constitue un enjeu pour les futures politiques de gestion de la qualité de l’air. Le programme PRIMEQUAL DECOMBIO (2013-2018) a été proposé afin de mettre en place des méthodologies permettant d’évaluer l’impact de cette opération sur les concentrations de PM10 à partir de mesures de terrains. Ce programme DECOMBIO, qui a servi de cadre à ce travail de thèse, s’est appuyé sur la confrontation durant 4 hivers des mesures en continu des PM10 issus de la combustion de la biomasse (noté PM10wb), des conditions météorologiques, et des variations d’émissions liées au renouvellement des appareils. Pour répondre à cet enjeu, les travaux de cette thèse ont eu pour objectif de développer des méthodes permettant de prendre en compte l’influence des conditions atmosphériques sur les concentrations hivernales de PM10 et d’évaluer les paramètres et facteurs d’incertitudes permettant de comparer les variations estimées d’émissions de PM10wb avec celles des concentrations mesurées de PM10wb au cours des 4 hivers.Ces travaux se sont appuyés sur d’importantes bases de données de mesures chimiques et météorologiques constitués durant 4 hivers (13-14 à 16-17) au niveau de 3 sites dans la vallée de l’Arve. Par ailleurs, les données techniques issues des dossiers de renouvellements des appareils pour bénéficier de l’aide financière du Fonds Air Bois nous ont été communiquées, nous permettant de spatialiser et temporaliser les réductions des émissions de PM10wb estimées provenant de ces remplacements d’appareils. L’état de la stabilité thermique de l’atmosphère, paramètre essentiel pour déterminer les épisodes d’inversions thermiques, a été suivi en continu grâce à un système peu onéreux de capteurs de température sous abris installés le long des pentes. Ces mesures ont permis de montrer que les conditions météorologiques locales dans ces vallées encaissées sont le facteur premier conditionnant les concentrations atmosphériques. Une classification automatique des conditions atmosphériques a été établie, permettant de s’affranchir de cette variabilité et de comparer les concentrations pour des conditions atmosphériques similaires entre les différents hivers. L’innovation de cette approche repose principalement sur la prise en compte du degré d’influence de variables météorologiques et de paramètres liés à l’intensité des émissions. Une diminution graduelle des concentrations de PM10wb au cours des hivers a ainsi pu être constatée au niveau des 3 sites pour certaines classes de conditions atmosphériques, résultat consolidé par la diminution concomitante des traceurs de la combustion de la biomasse à la masse des PM10. Afin de préciser ces résultats, nous nous sommes intéressés à estimer la réduction des émissions de PM10 des remplacements d’appareils au niveau des sites de mesures et leurs incertitudes.Au terme de ce travail et du programme DECOMBIO, nous avons été à même de développer et de valider plusieurs outils méthodologiques applicables dans l’évaluation de futurs fonds air bois (utilisation de capteurs le long des pentes, classification météorologique adaptée à la qualité de l’air, estimation des incertitudes sur les émissions de parc de dispositifs de chauffage au bois). Ces bases solides nous ont permis de mieux comprendre les mesures réalisées sur les PM atmosphériques, et leurs liens avec les estimations des émissions
Biomass burning, particularly residential wood burning, is a source of atmospheric particles that contributes significantly to winter PM10 levels globally in Europe. In order to reduce emissions from this source, a large-scale program for the renewal of non-efficient wood-burning appliances, the “Fonds Air Bois” has been launched since 2013 in the Arve Valley. The assessment of its impact on atmospheric concentrations is an issue for future air quality management policies. The research DECOMBIO program (2013-2018) has been proposed to evaluate the impact of this operation on PM10 concentrations from measurements. This DECOMBIO program, which includes these thesis works, was based on the confrontation during 4 winters of continuous measurements of PM10 resulting from biomass burning (noted PM10wb), weather conditions, and emissions variations related to appliances renewal. To answer this challenge, the aim of this thesis was to develop methods to take into account the influence of atmospheric conditions on winter PM10 concentrations and to evaluate the parameters and uncertainties that make it possible to compare the estimated PM10wb emission variations with those of the measured PM10wb concentrations during the 4 winters.This work was based on large datasets of chemical and meteorological measurements made during 4 winters (13-14 to 16-17) at 3 sites in the Arve Valley. In addition, the technical data from wood appliances renewal files was provided to us, allowing us to spatially and temporally estimated reductions of PM10wb emissions from these appliances replacements. The state of atmospheric stability, an essential parameter for determining episodes of temperature inversions, has been continuously monitored thanks to an inexpensive system of sheltered temperature sensors installed along the slopes. These measurements have shown that local weather conditions in these valleys are the primary factor conditioning atmospheric concentrations. An automatic weather types classification has been established, making it possible to overcome this variability and to compare the concentrations for similar atmospheric conditions between the different winters. The innovation of this approach is mainly based on taking into account the degree of influence of meteorological variables and parameters related to the intensity of emissions. A gradual decrease of PM10wb concentrations during winters was thus observed at the 3 sites for certain weather types, a result consolidated by the concomitant decrease in tracer biomass combustion at the mass of PM10. To clarify these results, we were interested in estimating the reduction of PM10 emissions from device replacements at measurement sites and their uncertainties.At the end of this work and of the DECOMBIO program, we have been able to develop and validate several methodological tools applicable in the evaluation of future “fonds air bois” (use of sensors along the slopes, meteorological classification adapted to the quality of the air, estimation of uncertainties on wood appliances renewable emissions). This solid foundation has allowed us to better understand the measurements made on atmospheric PM, and their relationship to emission estimates

Att minska energianvändningen är något det pratats mer och mer om de senaste åren. Det finns olika sätt att minska energianvändningen på och ett av dessa är att återvinna värmeenergi. Det kan gälla både spillvärme och nyttig värme. Detta går att tillämpa i industrin, transportsektorn, hushåll och till vardags. Gemensamt för dessa processer är att det används stora mängder energi vilket till stor grad består av förluster till omgivningen eller att processerna inte optimeras. På senare tid har det forskats kring teknologi som kan ta vara på denna värmeenergi och på så vis minska förlusterna. En teknologi för detta är termoelektriska generatorer (TEG) som bygger på Seebeckeffekten för att generera elektricitet från temperaturskillnader. När ett TEG-element utsätts för värme på en sida och kyla på den andra sidan så genereras en elektrisk spänning. En elektrisk ström och effekt kan tas ur kretsen om elementet kopplas till en elektrisk last. Materialet i elementet består av halvledarmaterial med låg värmeledningsförmåga och en hög elektrisk ledningsförmåga. Teknologin har funnits länge men aldrig tillämpats i någon större grad. Nu på senare år har intresset ökat och kommersiella produkter med TEG-element har tagits fram. I detta arbete har en sådan produkt testats för att se hur lämpligt det skulle vara att använda dessa vid hushåll som inte är anslutna till elnätet och har en vedkamin för uppvärmning. TEG-enheten testas på en värmeplatta där ställbara temperaturer är möjliga för att testa prestandan vid temperaturerna 150° C, 200° C och 230° C. En krets sätts ihop för att kunna mäta av värden på spänning och ström vid olika laster som sätts med resistorer. Mätningarna görs med en ökning på 0,1 A vid varje mätning. Resultatet från dessa tester visar att maximal effekt på 14 W uppnås hos produkten vid 230° C. När modifiering av produkten görs för att öka temperaturskillnaden uppnås 17,8 W vilket tyder på att effekten ökar när delta T ökar. Den spänning som uppnås vid öppen krets var som högst 31 V och vid maximal effekt var den 17,8 V. Strömmen var då 1 A. De resultat som testerna gav levde inte upp till de 25 W som produkten sägs kunna ge. Produkten saknar även viktiga komponenter så som spänningsreglerare.Det går av både teori och tester avgöra att det är ett lämpligt sätt att använda sig av TEG-enheter för att generera små mängder elektricitet vid hushåll utan koppling till elnätet.
In recent years the topic of reducing the energy usage has been on the agenda. There are several ways of reducing the energy usage and one of these is to recycle heat energy. It could be both waste heat and useful heat. This can be implied to the industry, transport sector, households and on daily activities. The common factor between these is that large quantities of energy is used and to a large extent consists of losses to the surrounding or from processes that are not optimized. In recent time there has been done research around technology that can recycle and use this heat energy and in return reduce the energy usage. One technology to do this is thermoelectric generators (TEG) that are implementing the Seebeck effect to generate electricity from temperature differences. When a TEG-element have one side that is exposed to a heat source and one side being cooled down an electric voltage is being generated. An electric current and power can then be used from the circuit if the element is connected to an electric load. The material in the element exists of semiconductive materials with low heat conductivity and high electric conductivity. The technology has existed for a long time but has never been implemented to a larger extent. It is only in recent years that the interest has grown and some commercial products with TEG-elements has been developed. In this thesis one of these products has been tested to see how viable it would be to use these within a household that is not connected to the electrical grid and where the house is heated with a wood-burning stove. The TEG-product is tested on a heat plate where it is possible to set a desired temperature. The temperatures of 150° C, 200° C and 230° C are chosen for testing the performance of the product. A circuit is put together to be able to read the values of the voltage and current at different loads that are set with resistors. The measurements are done with an increase of 0,1 A for every measurement. The result from these tests shows that the maximum power of 14 W is achieved at 230° C on the hot side. But when modification of the product is made to increase the temperature difference a value of 17,8 W is attained. This indicate that the power is increasing when the temperature difference is increasing. The attained voltage at open circuit was as highest 31 V and at maximum power it was 17,8 V. The current was then 1 A. The results that the testing gave did not match the value of 25 W that the datasheet says the product can deliver. Also, the product is missing important components such as voltage regulator.It is possible from both the theory and the testing to see that it is suitable to use a TEG-product to generate small amount of electricity to households that are not connected to the electrical grid.

Denna avhandling behandlar rökgasutsläpp av persistenta organiska föroreningar, framförallt dioxiner, vid förbränning av fasta biobränslen och torrt hushållsavfall i relativt små anläggningar (5-600 kW) utan avancerad rökgasreningsteknik.

Samförbränning av avfall och biobränsle i effektiva mindre biobränslepannor testades som en alternativ strategi till den vanligen förekommande storskaliga hanteringen och förbränningen fast hushållsavfall. Medan storskalig förbränning av avfall ger investeringsmässiga fördelar med rökgasreningsteknik etc. kan små lokala anläggningar ha transportmässiga fördelar och möjligheter till utnyttjande av lokala biobränsletillgångar. Källsorterat, torrt, brännbart hushållsavfall insamlades från hushåll i glesbygd och samförbrändes i brikettform med energigräset rörflen i 150-600 kW biobränslepannor. Endast undantagsvis understeg dioxinemissionerna gällande gränsvärden för avfallsförbränning och nivåerna av väteklorid i rökgas översteg gränsvärdena flerfaldigt. Det bedömdes att någon form av extra rökgasrening är nödvändig för att säkerställa nivågränserna. Dioxiner hittades också i det eldade avfallet, framförallt i textilfraktionen. Dioxinmängderna i rökgaserna var oftast lägre än i det ingående bränslet.

Intermittent pelletseldning gav oväntat höga utsläpp av dioxiner med en emissionsfaktor på 28 ng(WHO-TEQ)/kg. Vedeldning i en modern miljömärkt villapanna gav betydligt lägre utsläpp av dioxiner än eldning i en gammal kombipanna och eldning med full lufttillförsel, som kan jämföras med användning av ackumulatortank, resulterade i upp till 90% minskning av utsläpp av dioxiner jämfört med eldning med reducerat lufttillskott (’pyreldning’). Eldning av plastavfall i en vedpanna gav höga utsläpp av dioxiner.

Okontrollerad förbränning av trädgårdsavfall och hushålls avfall i tunna eller som öppen eld ’bakgårdsbränning’, gav stora variationer i utsläppsnivåer som bara delvis kunde kopplas till avfallsinnehåll. Resultaten visar att denna typ av förbränning kan vara en betydande källa till dioxiner i miljön, och ett emissionsfaktorintervall på 4-72 ng (WHO-TEQ)/kg föreslås för bedömningar av utsläpp från backgårdsbränning av avfall med låga eller måttliga klorhalter.

En sammanfattande slutsats av alla försök är att dioxin utsläpp beror på komplicerade samband mellan bränsleinnehåll och förbränningsbetingelser. Bränslen med mycket höga klorhalter av ger oftast högre utsläpp av dioxiner än bränslen med låga klorhalter medan små skillnader döljs av variationer i förbränningsbetingelser.

This thesis deals with emissions of persistent organic pollutants, primarily dioxins, from the combustion of solid biofuels and dry combustible household waste in relatively small facilities, 5-600 kW, without advanced air pollution controls.

Co-combustion of waste and biofuel in effective small boilers was tested as an alternative to prevailing large-scale management and combustion strategies for handling municipal solid waste. This approach includes no advanced air pollution control systems, but offers two advantages: limiting transport and providing scope to use local biofuel resources. Source-sorted, dry, combustible household waste was collected from households in a sparsely populated area and co-combusted as briquettes together with reed canary-grass in 150-600 kW biofuel boilers. Most trials showed difficulties to meet regulative limits for the emissions of dioxins valid for incineration of MSW and the regulated limits for emissions of hydrochloric acid were exceeded manifold. It was concluded that additional flue-gas cleaning will be needed to ensure that emissions are sufficiently low. Dioxins were also found in the waste, especially in the textile fraction. The mass of dioxins in the flue-gas emissions was generally lower than the mass in the fuel input.

Intermittent combustion of wood pellets in a residential boiler resulted in an unexpectedly high dioxin emissions factor of 28 ng (WHO-TEQ)/kg fuel. Combustion of wood in a modern environmentally certified boiler yielded considerably lower dioxin emissions than combustion in an old boiler, and combustion with a full air supply, i.e. with use of heat storage tank, resulted in up to 90% reductions in dioxin emission factors compared to combustion with reduced air supply. Combustion of plastic waste in a residential wood boiler resulted in high emissions of dioxins.

Tests of uncontrolled combustion of garden and household waste in barrels or open fires, ‘backyard burnings’, resulted in emissions with large variations that could only be partly correlated to the waste constituents. The results imply that this may be an important source of dioxins in the environment and an emission factor range of 4-72 ng (WHO-TEQ)/kg is suggested for estimating emissions from backyard burnings of lightly and moderately chlorine-contaminated waste.

A summarized conclusion from all of the experiments is that predicting emission levels from waste contents is not straightforward (except that fuels with very high chlorine levels will usually result in high levels of dioxins in flue-gas emissions). Moderate differences in chlorine levels will usually be masked by the effect of variations in combustion conditions.

Air pollutants pose a high risk for humans, and the environment, and this pollution is one of the major environmental problems facing modern society. Active air sampling is the technique that has been traditionally used to monitor nonpolar aromatic air pollutants. However, active high volume samplers (HiVols) require a power supply, maintenance and specialist operators, and the equipment is often expensive. Thus, there is a need to develop new, less complicated sampling techniques that can increase the monitoring frequency, the geographical distribution of the measurements, and the number of sites used in air monitoring programs. In the work underlying this thesis, the use of semipermeable membrane devices (SPMDs) as tools for monitoring gas phase concentrations of nonpolar aromatic compound was evaluated using the compound classes polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs (alkyl-PAHs) and nitrated PAHs (nitro-PAHs) as test compounds.

High wind-speeds increased the uptake and release in SPMDs of PAHs and PCBs with log K_OA values > 7.9, demonstrating that the uptake of most nonpolar aromatic compounds is controlled by the boundary layer at the membrane-air interface. The use of a metal umbrella to shelter the SPMDs decreased the uptake of PAHs and PCBs by 38 and 55 percent, respectively, at high wind/turbulence, and thus reduced the wind effect. Further, the use of performance reference compounds (PRCs) to assess the site effect of wind on the uptake in SPMDs reduced the between-site differences to less than 50 percent from as much as three times differences in uptake of PCBs and PAHs. However, analytical interferences reduced the precision of some PRCs, showing the importance of using robust analytical quality control.

SPMDs were shown to be efficient samplers of gas phase nonpolar aromatic compounds, and were able to determine local, continental and indoor spatial distributions of PAHs, alkyl- PAHs and nitro-PAHs. In addition, the use of the SPMDs, which do not require electricity, made sampling possible at remote/rural areas where the infrastructure was limited. SPMDs were also used to determine the source of PAH pollution, and different approaches were discussed. Finally, SPMDs were used to estimate the importance of the gas phase exposure route to the uptake of PAHs in plants. The results demonstrate that SPMDs have several advantages compared with HiVols, including integrative capacity over long times, reduced costs, and no need of special operators, maintenance or power supply for sampling. However, calibration data of SPMDs in air are limited, and spatial differences are often only semi-quantitatively determined by comparing amounts and profiles in the SPMDs, which have limited their use in air monitoring programs. In future work, it is therefore important that SPMDs are properly sheltered, PRCs are used in the sampling protocols, and that calibrated sampling rate data, or the SPMD-air partition data, of specific compounds are further developed to make determination of time weighted average (TWA) concentrations possible.

La pollution atmosphérique résulte d’un mélange complexe de composés, des gaz et des particules, dont les effets sont notoirement néfastes. Les composés organiques volatils (COV) tiennent un rôle prépondérant dans la chimie atmosphérique et sont précurseurs d’ozone et d’aérosols organiques secondaires (AOS). En Île-de-France, l’exposition à la pollution est préoccupante ; or, des incertitudes significatives sont toujours associées aux sources de polluants, ainsi qu’à leur intensité et leurs variabilités à différentes échelles de temps et très peu d’investigations ont porté sur la quantification de l’exposition individuelle. Dans ce contexte, cette thèse a cherché à mieux caractériser les variabilités temporelle et spatiale de la pollution en Île-de-France.La fiabilité discutable des capteurs portables a été dépassée par l’élaboration d’un protocole de sélection et de qualification comprenant différents tests en mesures fixes, en chambre et en mobilité. Cette nouvelle méthodologie, basée notamment sur l’utilisation d’un outil combinant différents indicateurs statistiques, a été appliquée pour retenir l’AE51, le Cairclip et le Canarin, mesurant respectivement le carbone suie (BC), le dioxyde d’azote (NO2) et les particules (PM).Ces trois capteurs ont été déployés au cours de campagnes de mesures impliquant une trentaine de volontaires. L’exposition individuelle ainsi quantifiée est plus élevée à l’automne qu’au printemps et varie de manière substantielle en fonction des différents environnements fréquentés. La proximité de la circulation routière (pour le BC et le NO2) ainsi que les activités de cuisine et la fumée de tabac (pour les PM) présentent des contributions importantes à l’exposition totale (jusqu’à 34 %, 26 % et 44 % respectivement), alors même que le temps passé dans ces environnements est faible.En plus du trafic routier, le BC est traditionnellement imputé au feu de bois. Une campagne hivernale de mesures (3,5 mois) a permis d’imputer respectivement 22 % et 47 % des COV mesurés à ces deux sources. Certains composés ont été mesurés et associés au feu de bois pour la première fois en air ambiant comme le benzènediol et le méthylbutènone. Une comparaison avec l’inventaire régional des émissions a permis d’identifier des similitudes et des différences pour proposer des améliorations
Air pollution results from a complex mixture of compounds, gases and particulate matter, whose effects have proven to be harmful. Volatile organic compounds (VOCs) play a major role in atmospheric chemistry and are precursors of ozone and secondary organic aerosols (SOAs). In Île-de-France, exposure to pollution is a concern; however, significant uncertainties are still associated with the pollutants’ sources, as well as their intensity and variability at different time scales, and very few investigations have focused on quantifying personal exposure. In this context, this research sought to better characterize the temporal and spatial variabilities of pollution in Île-de-France.The questionable reliability of portable sensors has been addressed by the design of a selection and qualification protocol including various tests in static measurements, controlled chamber and mobility. This new methodology, based in particular on the use of a tool combining different statistical indicators, was applied to choose the AE51, Cairclip and Canarin, measuring black carbon (BC), nitrogen dioxide (NO2) and particulate matter (PM) respectively.These three sensors were deployed during measurement campaigns involving about thirty volunteers. The personal exposure thus quantified is higher in fall than in spring and varies substantially according to the different environments frequented. Proximity to road traffic (for BC and NO2) as well as cooking activities and tobacco smoke (for PM) make significant contributions to total exposure (up to 34 %, 26 % and 44 % respectively), even though the time spent in these environments is short.In addition to road traffic, BC is traditionally attributed to wood burning. A winter measurement campaign (3.5 months) attributed respectively 22 % and 47 % of the measured VOCs to these two sources. Compounds including benzenediol and methylbuteone were measured and associated with wood burning for the first time in ambient air. A comparison with the regional emissions inventory identified similarities as well as differences and suggested improvements

碩士
國立成功大學
建築學系碩博士班
96
In recent years, our government carried out the Performance based code and design. Performance based design has become a legally usable design method in Taiwan. This design proved by date calculation, computer modeling and full-scale fire test. The performance based design need large data to prove the experiments. Fire experiment center research into full-scale fire test and fire load. There, wood crib is one of the fire load type. Study on burning behavior about fire growth and spread. They take provides for performance based design. Study research for burning behavior and characteristic about wood crib. Study on wood crib burning behavior by reference which from overseas and inland. This research adopts ISO 9705 room test to carry out wood crib experiments for fire simulation. Study on four types of wood crib, which set on different place in test room. From the results of wood crib burning experiments, when they place on corner, side and back side, wood crib burning fast. If sticks separated largely, fire need long time to spread. The HRR curve wood cribs will growing slowly, which so call platform phenomenon. In this experiment, wood crib was placed by 45 sticks. The coefficient of growth rate of fir in our experiment is between 0.00049~0.01362. A wood crib about 5n9L type can be classified as medium growth rate T-squared fire. The other types can be classified as slow growth rate.

博士
國立臺灣大學
機械工程學研究所
91
ABSTRACT The thermal and mass characteristics of single wood spheres burning in hot air flows were investigated by experiments and theories. The combustion characteristics of interest are: the pyrolysis temperature, the ignition temperature, and change of fuel properties and burning rate during combustion. The wood spheres were ignited by hot air flowing around the spheres at different flow rates. The burning process was interrupted with water quenching at different stages of combustion. Samples of midway-burning wood spheres were inspected by X-ray and by dissection to investigate the wood sphere interior material changes. The materials at different locations inside the sphere were analyzed for the chemical composition distributions. The experiments provide extensive data allowing the analysis of wood sphere burning rates and thermochemical characteristics during different stages of combustion. A correlation for estimating wood sphere burning rates was proposed. In general, the experiments showed that the wood pyrolysis temperatures were heating rate dependent. The inner part of the burning wood spheres during the stage prior to char combustion, albeit under thermal decomposition, analysis of material composition showed that the atomic ratios of H and O of the material, irrespective of the location, were essentially within a close range during either pyrolysis or flaming combustion. The energy of conduction, convection, chemical reaction, moisture evaporation, and combustion are addressed to understand by theory analysis. The burning rate of char combustion is also discussed in this work.

M. Tech. Architectural Technology
South Africans are faced with the challenge of becoming less dependent on fossil-based electricity (which is very commonly used in the heating of homes), because it is not only becoming less affordable, but also less sustainable. Wood-burning fireplaces have developed over thousands of years, and an analysis thereof reveals that a correctly designed and constructed wood-burning masonry fireplace is a valid alternative to electrical heaters. The research design consists of a survey of existing wood-burning masonry fireplaces and chimneys in South Africa. This study investigates a number of design elements, including the size of the room, fireplace, and chimney, as well as the height of the chimney. The traffic patterns that cause draughts, including furniture arrangements, and safety regulations, are also included.

Within the context of global climate change and soaring energy prices, people are searching for inexpensive and renewable sources of energy; therefore, burning wood for home heating is increasing. Woodsmoke contains substances known to harm human health and is a major contributor to air pollution in many parts of the world; yet there is limited research into the health effects of woodsmoke and existing research suffers from methodological constraints. As a result, there is interest in producing robust woodsmoke exposure estimates for health research and air quality management purposes. Studying health and the environment is inherently spatial; however, research related to air pollution and health tends to be aspatial. As investigators begin to understand the influence of spatial processes on research findings, the importance of adopting a spatial approach to modelling exposure and health risk is becoming apparent. This thesis describes a spatially explicit model for predicting fine particulate matter (PM2.5) attributable to woodsmoke from residential heating in Victoria, British Columbia, Canada. Spatially resolved measurements of PM2.5 were collected for 32 evenings during the winter heating seasons of 2004/05, 2005/06, 2006/07 using a nephelometer installed in a passenger vehicle. Positional data were collected concurrently using a Global Positioning System (GPS). Levoglucosan, a chemical unique to woodsmoke, was measured to confirm the presence of woodsmoke in the measured PM2.5. The spatial scale for the analysis of woodsmoke data was determined using semivariograms to identify the maximum distance of spatial dependence in the data which typically occurred near 2700m. Different spatial approaches for modelling woodsmoke concentrations were evaluated both qualitatively in terms of transferability, meeting statistical assumptions, and potential for exposure misclassification; and quantitatively to assess the association between the model’s predicted PM2.5 concentrations and observed PM2.5. The baseline model characterized exposure based on the PM2.5 value from the closest fixed monitor (R=0.51, α=0.05). The Krigged model produced a seasonal average surface based on nephelometer measurements and showed the weakest performance (R=0.25, α=0.05). The regression models predicted concentrations of woodsmoke based on predictor variables available from census data, typically used in health research, and spatial property assessment data (SPAD), an underused data source at a finer spatial resolution. Different approaches to regression modelling were investigated. A regression model already developed for Victoria performed the best quantitatively (R=0.84, α=0.05); however, qualitative considerations precluded it from being selected as an appropriate model. A quantitatively (R=0.62, α=0.05) and qualitatively robust regression model was developed using SPAD (M6). SPAD improved the spatial resolution and model performance over census data. Removing spatial and temporal autocorrelation in the data prior to modelling produced the most robust model as opposed to modelling spatial effects post regression. A Bayesian approach to M6 was applied; however, model performance remained unchanged (R=0.62, α=0.05). The spatial distribution of susceptibility to health problems associated with woodsmoke was derived from census data relating to population, age and income. Intersecting the exposure model with population susceptibility in a Geographic Information System (GIS) identified areas at high risk for health effects attributable to woodsmoke.

In Australia there has been a sharp increase in residential wood-heating since the late 1970s, and the trend is expected to continue for some years. Overseas research has shown that, under certain conditions, wood-heating can be a source of serious air pollution problems. The particulates resulting from wood-burning appliances are primarily organic in nature and, being in the respirable size range, can cause a variety of health ailments including cancer. The reaction of affected communities overseas has been varied. New Zealand followed the British example by allowing Christchurch to be declared a Clean Air Zone, but the results are not comparable to those achieved in Britain. In the United States, the Environmental Protection Agency has proposed a new source performance standard for wood-burning appliances which will become effective in July 1988. However, a number of control measures are already in force in several states and towns. In Europe, voluntary performance certification of appliances occurs in the Netherlands and Switzerland; and fire insurance premiums are linked to regular inspections and maintenance in France. In Australia, there is currently no co-ordinated control strategy to deal with this potential problem. Only the New South Wales Clean Air Act gives limited powers to local councils. Recently some brochures on wood-heater smoke reduction have been published and are available in some states. A standard measurement technique is of vital importance in controlling pollution. In wood-heater applications this has been lacking and the task of its development is made difficult by the non-discrete nature of the particulates in wood-smoke as well as the variations in the wood-burning process. An assortment of methods have been used to measure particulate emissions from wood-heaters. Oregon Method 7 was the first "standard method" for this source, and is a modification of EPA Method 5. The ASTM has proposed a dilution tunnel method which is finding popular support; it has been accepted by the New Zealand Clean Air Council as the \Standard Method, and also by the US EPA. Another dilution method is the Condar Method which has been accepted by the Oregon DEQ as equivalent to OM-7. This is a very simple and relatively inexpensive method which can identify periods of high emissions during a burn. This method was used in the experimental part of this study. Seventy three tests were conducted on two models of heaters (one catalytic and the other non-catalytic) using three types of fuel wood and varying fuel loads and burn rates. Statistical analysis revealed no difference between the catalytic and the non-catalytic models and no effect of varying burn rates on emissions; emissions increased with larger fuel loads for one fuel wood type, whereas for the other two types there was no significant increase. Correlations between particulate emissions and average flue gas concentrations of 02, co2, and CO were very poor. Particulate emission factors obtained during the experimental programme ranged from 0. 4 to 32. 7 g/kg (0. 9 to 56 .1 g/h) with an average of 8. 2 g/kg (15 .1 g/h) for eucalypt firewood. Lower emissions were obtained for eucalypt and pine brands; with eucalypt brands the range was 0.4 to 4.4 g/kg (0.9 to 13.9 g/h) with an average of 1.8 g/kg (4.4 g/h), whereas for pine brands the range was 1.3 to 5.5 g/kg (2.6 to 13.5 g/h) with an average of 3.3 g/kg (7.2 g/h). On the basis of this study it is recommended that detailed studies be initiated to estimate the impact of this source on ambient air quality in the areas where wood-burning is popular. This should then lead to the formulation of an appropriate control strategy. Meanwhile, greater importance should be given to public education programmes.

Student Number : 0306319G - MSc Research Report - School of Geography, Archaeology and Environmental Studies - Faculty of Science
Combustion of fuel wood, charcoal and non-woody biofuels is a daily practice for about half of the world’s population. Combustion of biofuel is a major source of trace gases, with domestic biomass burning contributing about 17% carbon dioxide (CO2), 13% carbon monoxide (CO) and 6% nitrous oxide (N2O) to the global budget. In Africa, where there is a growing population, domestic biofuel emissions are a particularly important source of trace gases. The most important source of biomass fuels in Africa is wood fuel (wood and charcoal), crop residues and animal dung. In this project, the amount of domestic biofuel used in rural households across southern Africa was measured daily over a nine month period. This data was used to estimate the trace gas production from domestic fires throughout Southern Africa. Results indicate that RSA contributed the most trace gases to the regional budget (9.12 Tg C yr-1 of CO2, 0.89 Tg C yr-1 of CO, 10.77 Gg N yr-1 of NO and 30.25 Gg C yr-1 of CH4) and Botswana the least (0.25 Tg yr-1 of CO2, 0.02 Tg yr-1 of CO, 0.29 Gg yr-1 of NO and 0.83 Gg yr-1 of CH4). Fuel wood is the dominant fuel type used in all southern African countries, whereas charcoal was used in RSA, Mozambique and Zambia and maize residues in Malawi only. CO2 was the gas emitted in the largest quantities, with fuel wood and charcoal in RSA contributing the most (8.71 Tg yr-1 and 0.41 Tg yr-1 respectively), while CO2 from maize residue was highest in Malawi (0.82 Tg yr-1). More trace gases were emitted in the dry season than wet season particularly in Malawi and Mozambique. For the entire region the annual CO2, CO, NO and CH4 emissions produced 23.0 Tg C, 2.2 Tg C, 29.4 Gg N and 81.4 Gg C, respectively.

Atmospheric aerosol is an important component of our atmosphere influencing human health, regional and global atmospheric chemistry and climate. The organic component of submicron aerosol contributes around 50% of its mass and is a complex mixture of tens of thousands of compounds. Real-time aerosol mass spectrometry was the major measurement tool used in this work. The Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) can quantitatively measure the chemical composition and size distribution of non-refractory submicron aerosol (NR-PM1). The mass spectra provided by the instrument every few minutes contain information about aerosol sources and processes. This thesis uses the HR-ToF-AMS measurements in two areas of Greece to quantify the contributions of organic aerosol sources to the corresponding organic aerosol levels. Local and regional air pollution sources were monitored and characterized in two sites during intensive campaigns. The first campaign took place during the fall of 2011 (September 24 to October 23) in Finokalia, Crete, a remote-background coastal site without any major human activity. The aim of the study was to quantify the extent of oxidation of the organic aerosol (OA) during autumn, a season neither too hot nor cold, with reduced solar radiation in comparison to summer. The second one took place during the winter of 2012 (February 26 to March 5), in the third major city of Greece, Patras. The measurements were conducted in the campus of the Technological Educational Institute of Patras (TEI), in order to quantify the severity of the wintertime air pollution problem in the area and its sources. The contributions of traffic and residential wood burning were the foci of that study. The Finokalia site is isolated and far away from anthropogenic sources of pollution, making it ideal for the study of organic aerosol coming from different directions, usually exposed to high levels of atmospheric oxidants. The fine PM measured during the Finokalia Atmospheric Measurement Experiment (FAME-11) by the AMS and a Multi Angle Absorption Photometer (MAAP) was mostly ammonium sulfate and bisulfate (60%), organic compounds (34%), and BC (5%). The aerosol sampled originated mainly from Turkey during the first days of the study, but also from Athens and Northern Greece during the last days of the campaign. By performing Positive Matrix Factorization (PMF) analysis on the AMS organic spectra for the whole dataset the organic aerosol (OA) composition could be explained by two components: a low volatility factor (LV-OOA) and a semi-volatile one (SV-OOA). Hydrocarbon-like organic aerosol (HOA) was not present, consistent with the lack of strong local sources. The second field campaign took place in the suburbs of the city of Patras, 4 km away from the city center during the winter of 2012. During this 10-day campaign, organics were responsible for 70% during the day and 80% during the evening of the total PM1. The OA mean concentration during that period was approximately 20 μg m-3 and reaching hourly maximum values as high as 85 μg m-3. Sulfate ions and black carbon followed with 10% and 7% of the PM1. PMF analysis of the organic mass spectra of PM1 explained the OA observations with four sources: cooking (COA), traffic (HOA), biomass burning (BBOA), and oxygenated aerosol (OOA), related to secondary formation and long range transport. On average, BBOA represented 58% of the total OM, followed by OOA with 18%, COA and HOA, with the last two contributing of the same percentage (12%).
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Fire is the primary natural disturbance vital to the ecological integrity of Quetico Provincial Park, Ontario, Canada. A new provincial park planning process (i.e., Class Environmental Assessment) has required the review of Quetico’s Fire Management Plan. To support this review, large and severe (stand-replacing) Quetico fires were studied using 1966 Ontario Ministry of Natural Resources (OMNR) forest resource inventory (FRI) mapping. A Geographic Information Systems (GIS) database of the FRI was created and updated with the OMNR digital fire atlas. This database was used as a time-since-fire and fire interval dataset to estimate fire frequency. It also served to archive the 1966 FRI for the largest protected area in the transition between the Boreal and Great Lakes-St. Lawrence forest regions. Non-parametric (Kaplan-Meier) survival analysis was used to estimate survival functions and mean fire intervals (i.e., the expected time between two consecutive stand-replacing fires for any location within the Park). Previous studies that have used Kaplan-Meier survival analysis methods have based fire frequency estimates solely on time-since-fire data. However, time-since-fire data cannot be equated with fire interval data when using non-parametric methods. At least one fire interval is required to obtain reliable results. The mean fire interval for the entire 475,782 ha Park between the years 1668 and 2007 was 230 years. Performing the analysis on various geographic and temporal partitions revealed fire frequency spatial and temporal variability. A constant (independent of time-since-fire) probability of burning was not observed for Quetico which is contrary to accepted conjecture for northwestern Ontario boreal/mixed-wood forests. A current fire cycle was also estimated for the Park (342 years) using the digital fire atlas. The results suggested that use of historical static fire frequency estimates as fire management prescriptions may not be justified given considerable fire frequency temporal variability. The observed fire frequency spatial variability suggests that studies should be undertaken at coarser scales than is the norm to characterise the regions fire regime in support of landscape level fire management planning.