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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Investigating preferences for low emission buses

Loría Rebolledo, Luis Enrique January 2018 (has links)
This thesis aims to investigate preferences for Low Emission Buses (LEB). Building on the existing stated preference literature on bus service quality measures and emissions reduction valuation in private vehicles and on the few existing studies looking at LEBs, which have used Contingent Valuation, this study makes use of the multi-attribute nature of Discrete Choice Experiments (DCE) to explore valuations for reductions in two different types of emissions separately, along with other attributes traditionally related to bus travel. This thesis uses a state-of-the-art pivoted experimental design to create reference-dependent choice tasks centred on the respondent's current experience. Choice task realism was additionally sought by using quantitative and qualitative research to inform the experimental and survey design. The survey was conducted at bus stops in the city of Aberdeen during the months of October and November 2016, whilst an existing LEB pilot project was in operation: the Aberdeen Hydrogen Bus Project (AHBP). Choice data is analysed using random parameter logit models to explore preferences for reductions in the two separate emissions and other bus service characteristics. To provide greater insight of the preferences for LEBs, this thesis' additional methodological contributions include using the AHBP as a case study to explore the role of familiarity on preference formation and examining whether choice behaviour is consistent with prospect theory's three main properties: reference dependence, changing marginal sensitivities and preference asymmetry in the form of loss aversion. Policy implications from each of these contribution are discussed.
112

Using a four-dimensional geographical information system to visualise the environmental impact of smog.

Sandison, Daniel C. January 1999 (has links)
This research was developed to investigate the potential environmental impacts of poor air quality in Perth. This involved improving existing vegetation maps (through satellite image analysis techniques) for biogenic or forest emissions as a precursor to smog in Perth. Further, to visualise potential environmental impacts associated with poor air quality, a four- dimensional (volumetric over time) animation was created which clearly shows the path and extent of smog in Perth throughout an entire day.Computer mapping of vegetation using Landsat TM data was performed to create an updated inventory of forest types in Perth as input into a photochemical smog model. By improving the inventory of forest cover, the Department of Environmental Protection (DEP) in Perth can calculate up to date biogenic emission estimates for the photochemical smog model.Outputs from the DEP's photochemical smog model were integrated into a Geographical Information System (GIS) and subsequently visualised to show plume movement and potential environmental impact. Two datasets (nitrogen oxides and ozone) were provided to investigate the volumetric and dynamic temporal movement of photochemical smog in Perth on one day, March 16, 1994.Nitrogen oxide sources can range from industry and petroleum refining to motor vehicle exhaust emissions, and are a major precursor to photochemical smog (ozone) formation in Perth. Natural emission sources (forest or biogenic emissions) can also be an important contributing factor to the photochemical smog mix in Perth. Biogenic emissions are comprised of Reactive Organic Chemicals (ROC) or Volatile Organic Compounds (VOC) which act as a catalyst to aid the nitrogen oxide conversion to ozone.Three-dimensional and four-dimensional GIS techniques were used to highlight both plume movement and environmental impact. These two sets of visualisations have differing ++ / chemical levels (higher and lower, respectively) to show movement and interaction effectively. Visualisation of the chemicals allows for a greater understanding of the mostly invisible chemical movement over the course of a day and its potential impact to humans and vegetation.The spatial and temporal interaction of the plumes was investigated by creating a series of animations that can be viewed over the Internet. By using multimedia capabilities, these results can be easily distributed to a wide range of decision makers and people generally interested in smog in Perth.
113

Inter-pollutant and reactivity-weighted air pollutant emission trading in Texas

Wang, Linlin, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
114

Signal Timing Optimization to Improve Air Quality

Lv, Jinpeng 1983- 14 March 2013 (has links)
This study develops an optimization methodology for signal timing at intersections to reduce emissions based on MOVES, the latest emission model released by U.S. Environmental Protection Agency (EPA). The primary objective of this study is to bridge the gap that the research on signal optimization at intersections lags behind the development of emissions models. The methodology development includes four levels: the vehicle level, the movement level, the intersection level, and the arterial level. At the vehicle level, the emission function with respect to delay is derived for a vehicle driving through an intersection. Multiple acceleration models are evaluated, and the best one is selected in terms of emission estimations at an intersection. Piecewise functions are used to describe the relationship between emissions and intersection delay. At the movement level, emissions are modeled if the green time and red time of a movement are given. To account for randomness, the number of vehicle arrivals during a cycle is assumed to follow Poisson distributions. According to the numerical results, the relative difference of emission estimations with and without considering randomness is usually smaller than 5.0% at a typical intersection of two urban arterials. At the intersection level, an optimization problem is formulated to consider emissions at an intersection. The objective function is a linear combination of delay and emissions at an intersection, so that the tradeoff between the two could be examined with the optimization problem. In addition, a convex approximation is proposed to approximate the emission calculation; accordingly, the optimization problem can be solved more efficiently using the interior point algorithm (IPA). The case study proves that the optimization problem with this convex approximation can still find appropriate optimal signal timing plans when considering traffic emissions. At the arterial level, emissions are minimized at multiple intersections along an arterial. First, discrete models are developed to describe the bandwidth, stops, delay, and emissions at a particular intersection. Second, based on these discrete models, an optimization problem is formulated with the intersection offsets as decision variables. The simulation results indicate that the benefit of emission reduction become more and more significant as the number of intersections along the arterial increases.
115

Essays on the Economics of Public Health

Ward, Courtney 05 December 2012 (has links)
This dissertation considers the economics of public health in the context of respiratory disease, a leading cause of morbidity and mortality. The pervasive nature of respiratory illness represents a significant reduction to health and longevity, but private actions to prevent illness may not consider the full-scale benefit of societal health improvement. In this thesis, I consider two determinants of respiratory illness: (1) the spread of influenza disease and (2) air pollution. In both cases, public policy aims to attenuate the effects of these factors by incentivizing or mandating preventative action. Because such interventions come at a cost, it is important to consider the magnitude of benefits associated with these actions. I consider each determinant in turn. First, I provide causal evidence on the health and economic consequences of an ongoing broad-scope vaccination program. The Ontario Influenza Immunization Campaign expanded the scope of vaccine coverage leading to a 20-percent increase in vaccination. Using the timing of this campaign and exogenous variation in vaccine quality, I link higher vaccination rates to decreases in lost-work-time, hospitalization, and death. Results indicate that, when vaccine quality is high, the program leads to higher gains for Ontario relative to other provinces and in short, an ounce of prevention is worth a pound of cure. Second, I provide evidence of the impact of air pollution on respiratory health. Recent changes in standards for air pollution are highly contentious and represent stringent constraints on economic activity. Evidence from this dissertation directly informs this debate. By linking daily pollution to hospital admissions for municipalities across Ontario, I study the impact of air pollution at levels below those historically considered. Results indicate that particulate matter has a significant effect on respiratory health of children but that ozone and carbon monoxide have little effect on respiratory hospitalizations for all age groups.
116

Essays on the Economics of Public Health

Ward, Courtney 05 December 2012 (has links)
This dissertation considers the economics of public health in the context of respiratory disease, a leading cause of morbidity and mortality. The pervasive nature of respiratory illness represents a significant reduction to health and longevity, but private actions to prevent illness may not consider the full-scale benefit of societal health improvement. In this thesis, I consider two determinants of respiratory illness: (1) the spread of influenza disease and (2) air pollution. In both cases, public policy aims to attenuate the effects of these factors by incentivizing or mandating preventative action. Because such interventions come at a cost, it is important to consider the magnitude of benefits associated with these actions. I consider each determinant in turn. First, I provide causal evidence on the health and economic consequences of an ongoing broad-scope vaccination program. The Ontario Influenza Immunization Campaign expanded the scope of vaccine coverage leading to a 20-percent increase in vaccination. Using the timing of this campaign and exogenous variation in vaccine quality, I link higher vaccination rates to decreases in lost-work-time, hospitalization, and death. Results indicate that, when vaccine quality is high, the program leads to higher gains for Ontario relative to other provinces and in short, an ounce of prevention is worth a pound of cure. Second, I provide evidence of the impact of air pollution on respiratory health. Recent changes in standards for air pollution are highly contentious and represent stringent constraints on economic activity. Evidence from this dissertation directly informs this debate. By linking daily pollution to hospital admissions for municipalities across Ontario, I study the impact of air pollution at levels below those historically considered. Results indicate that particulate matter has a significant effect on respiratory health of children but that ozone and carbon monoxide have little effect on respiratory hospitalizations for all age groups.
117

Internet GIS for Air Quality Information Service for Dalian, China

Shen, Lisai January 2005 (has links)
Since the 1970s, environmental monitoring in China has formed a complete web across the country with over 2000 monitoring stations. China State Environmental Protection Administration (SEPA) has published an annual report on the State of the Environment in China since 1989. The Chinese government began to inform the public of environmental quality and major pollution incidents through major media since the late 1990s. However, environmental quality data has not been adequately used because of constraints on access and data sharing. The public and interested groups still lack access to environmental data and information. After examining the current air quality reporting systems of the US Environmental Protection Agency and the Ontario Ministry of Environment, reviewing current Internet GIS technology and sample websites, this thesis developed an ArcIMS website to publish air quality data and provide background information to the public for the city of Dalian, China. The purpose is to inform the public of daily air quality and health concerns, and to improve public awareness of environmental issues. A better-informed and educated public will be more likely to voluntarily conserve the environment in the long run. The development of this thesis can satisfy most basic expectations. However, due to the limitation of current Internet products like ArcIMS, symbology and connection with outside databases are not adequate. In addition some regular GIS analysis functions are not available to Internet GIS products. This development can be further improved to serve other environmental data to the public with better interactivity through coding. Similar Internet GIS products can be used in other Chinese cities to report their air quality data. For internal data sharing and reporting within the government, an open, interoperable distributed GIService is recommended, which is believed to be the future of Internet GIS.
118

Internet GIS for Air Quality Information Service for Dalian, China

Shen, Lisai January 2005 (has links)
Since the 1970s, environmental monitoring in China has formed a complete web across the country with over 2000 monitoring stations. China State Environmental Protection Administration (SEPA) has published an annual report on the State of the Environment in China since 1989. The Chinese government began to inform the public of environmental quality and major pollution incidents through major media since the late 1990s. However, environmental quality data has not been adequately used because of constraints on access and data sharing. The public and interested groups still lack access to environmental data and information. After examining the current air quality reporting systems of the US Environmental Protection Agency and the Ontario Ministry of Environment, reviewing current Internet GIS technology and sample websites, this thesis developed an ArcIMS website to publish air quality data and provide background information to the public for the city of Dalian, China. The purpose is to inform the public of daily air quality and health concerns, and to improve public awareness of environmental issues. A better-informed and educated public will be more likely to voluntarily conserve the environment in the long run. The development of this thesis can satisfy most basic expectations. However, due to the limitation of current Internet products like ArcIMS, symbology and connection with outside databases are not adequate. In addition some regular GIS analysis functions are not available to Internet GIS products. This development can be further improved to serve other environmental data to the public with better interactivity through coding. Similar Internet GIS products can be used in other Chinese cities to report their air quality data. For internal data sharing and reporting within the government, an open, interoperable distributed GIService is recommended, which is believed to be the future of Internet GIS.
119

Evaluating Surface Concentrations of NO2 and O3 in Urban and Rural Regions by Combining Chemistry Transport Modelling with Surface Measurements

Rebello, Zena January 2010 (has links)
A base case modelling investigation was conducted to explore the chemical and physical behaviour of ground-level ozone (O3) and its precursor nitrogen dioxide (NO2) in Ontario using the U.S. Environmental Protection Agency (EPA) Community Multiscale Air Quality (CMAQ) model. Two related studies were completed to evaluate the performance of CMAQ in reproducing the behaviour of these species in both rural and urban environments by comparing to surface measurements collected by the Ontario Ministry of the Environment (MOE) network of air quality stations. The first study was a winter examination and the second study was conducted for a period during the summer of the same year. The municipality of North Bay was used to represent a rural setting given its smaller population relative to the city of Ottawa which was the base of the urban site. Statistical and graphical analyses were used to validate the model output. CMAQ was found to replicate the spatial variation of O3 and NO2 over the domain in both the winter and summer, but showed some difficulty in simulating the temporal allocation of the species. Validation statistics for North Bay and Ottawa showed overall O3 mean biases (MB) of 3.35 ppb and 2.25 ppb, respectively, and overall NO2 MB of -8.75 ppb and -4.37 ppb, respectively for the winter. Summer statistics generated O3 MB of 4.66 ppb (North Bay) and 10.05 ppb (Ottawa) while both MB for NO2 were between -2.20 ppb to -2.55 ppb. Graphical analysis showed that the model was not able to reproduce the lower levels of O3, especially at night, or the higher levels of NO2 during the day at the North Bay site for either season. This was expected since the comparisons were made between point measurements and 36 km grid-averaged model results. The presence of high amounts of NO2 emissions local to the monitoring sites compared to the levels represented in the emissions inventory may also be a contributing factor. The simulations for Ottawa demonstrated better agreement between model results and measurements as CMAQ provided a more accurate reproduction of both the higher and lower mixing ratios of O3 and NO2 during the winter and summer seasons. Results indicate that CMAQ is able to simulate urban environments better than rural ones.
120

Spatial and temporal variations of PM2.5 mass and composition in Atlanta: ASACA 1999 2006

Cobb, Charles Evan 20 November 2006 (has links)
Starting in March of 1999, the ASACA study has measured PM2.5 mass and composition using 24-hr integrated and continuous measurement techniques. The ASACA network has one rural (Fort Yargo) and three urban (Fort McPherson, South Dekalb, and Tucker) monitoring sites located in the metropolitan Atlanta area. Supplementary data from the SEARCH and STN monitoring networks is also used where applicable. Yearly-averaged TEOM measurements recorded violations of the annual PM2.5 NAAQS (>15 μg/m3) every year of the study, and the daily NAAQS (>65 μg/m3) was exceeded on five separate occasions. Seven-year PM2.5 averages for the sites ranged from 18.8 – 19.8 μg/m3. PCMs were employed to collect PM2.5 composition data, detect spatial variations of PM species, and compare results with the continuous mass measurements. From 2004 – 2005, approximately 28% of the mass was OC, 24% was sulfate, 10% was ammonium, 6% was nitrate, and 3% was EC. Lesser ions contribute less than 3% to the total PM2.5 mass. Spatial variation of the major species was minimal, especially for species formed from secondary processes. South Dekalb did exhibit elevated levels of EC compared to the other sites, most likely due to its proximity to an interstate heavily used by diesel vehicles. PCM averages were found to be less than the averaged TEOM data due to the presence of unidentified matter (UM). Depending on the season, UM can contribute as little as 5% and as much as 50+% of the total mass. Secondary organic aerosol (SOA) concentrations from 2004 – 2005 were predicted using the EC-tracer method. Peak SOA occurs in mid-summer, and winter concentrations are significant due to biomass burning increasing the estimated OC/EC ratios. PCM, TEOM, and aethalometer data was also subjected to seasonal, day-of-the-week, and diurnal temporal variations. Active photochemistry plays an important role, as most species exhibit higher concentrations during summer months. The lone exception was nitrate, whose peak occurs in winter. Daily-averaged PM2.5 concentrations tend to peak late in the work-week and reach their low point on Sundays. Morning and afternoon rush-hour spikes in one-hour averaged PM2.5 are visible most days.

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