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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.
1

The New Zealand National Environmental Standards for ambient air quality: analysis and modelling case study

Thornton, David Phillip January 2007 (has links)
Historically, the New Zealand rationale behind air quality management has been to adopt an effects-based approach based on environmental impacts. Generally, this method has been efficient in that it permitted emitters to decide how to minimise and mitigate impacts. However, to address the inconsistencies in air quality management across New Zealand born of this approach, and to permit measures designed to improve the working of the Resource Management Act (RMA), National Environmental Standards for Ambient Air Quality have been developed and implemented to establish consistent regulation and protection for all New Zealanders. The standards were gazetted in September 2004, for full implementation by 2013. This thesis explores the implementation of the National Environmental Standards for Ambient Air Quality, examining the philosophy behind the standards and associated strategies for dealing with air pollution management in New Zealand, and the international context for the development of appropriate tools to address air quality concerns. The research also provides an independent dispersion modelling assessment of the application of the Ministry for the Environment's initiative regarding sulphur dioxide in the Marsden Point airshed, Northland, utilising The Air Pollution Model (TAPM) for a period when heightened concentration values had been recorded. The key outcomes of the thesis are: (i) 99.9th percentile and maximum values for the simulated two-day modelling case study are within those stipulated by the air quality standards for sulphur dioxide; (ii) modelled concentrations associated with shipping within the airshed of interest contribute significantly to total modelled values; (iii) the chief obstruction to increased use of the prognostic modelling approach is that of the unsatisfactory availability and integrity of emission inventories; (iv) performing long-term high-resolution simulations with multiple point sources is prohibitive due to computational demands; (v) good quality monitoring will always be required; (vi) the standards have broad and far-reaching implications for resource managers, resource users and possibly the economy of individual regions and the country as a whole; (vii) the successful implementation of the National Environmental Standards for Ambient Air Quality in New Zealand will integrate a thorough understanding of modelling, measurements, meteorology and emissions.
2

The New Zealand National Environmental Standards for ambient air quality: analysis and modelling case study

Thornton, David Phillip January 2007 (has links)
Historically, the New Zealand rationale behind air quality management has been to adopt an effects-based approach based on environmental impacts. Generally, this method has been efficient in that it permitted emitters to decide how to minimise and mitigate impacts. However, to address the inconsistencies in air quality management across New Zealand born of this approach, and to permit measures designed to improve the working of the Resource Management Act (RMA), National Environmental Standards for Ambient Air Quality have been developed and implemented to establish consistent regulation and protection for all New Zealanders. The standards were gazetted in September 2004, for full implementation by 2013. This thesis explores the implementation of the National Environmental Standards for Ambient Air Quality, examining the philosophy behind the standards and associated strategies for dealing with air pollution management in New Zealand, and the international context for the development of appropriate tools to address air quality concerns. The research also provides an independent dispersion modelling assessment of the application of the Ministry for the Environment's initiative regarding sulphur dioxide in the Marsden Point airshed, Northland, utilising The Air Pollution Model (TAPM) for a period when heightened concentration values had been recorded. The key outcomes of the thesis are: (i) 99.9th percentile and maximum values for the simulated two-day modelling case study are within those stipulated by the air quality standards for sulphur dioxide; (ii) modelled concentrations associated with shipping within the airshed of interest contribute significantly to total modelled values; (iii) the chief obstruction to increased use of the prognostic modelling approach is that of the unsatisfactory availability and integrity of emission inventories; (iv) performing long-term high-resolution simulations with multiple point sources is prohibitive due to computational demands; (v) good quality monitoring will always be required; (vi) the standards have broad and far-reaching implications for resource managers, resource users and possibly the economy of individual regions and the country as a whole; (vii) the successful implementation of the National Environmental Standards for Ambient Air Quality in New Zealand will integrate a thorough understanding of modelling, measurements, meteorology and emissions.
3

Source contributions of suspended particles using Air Quality Model and Receptor Model

Wang, Wen-Cheng 21 December 2008 (has links)
Air quality of the Kao-Ping airshed has been the worst of all airsheds which are divided into seven groups by districts in Taiwan. The percentage of annual bad air quality (Pollution Standard Index, PSI > 100) in the Kao-Ping airshed (6.65−13.56%) was twice than it in the Yun-Chia-Nan airshed (2.58−6.98%) during the past decade (1998−2007). Oil refineries, petrol/plastic industries, power plants, and iron/steel/metal plants are the major industries in the Kaohsiung metropolitan area. Due to intensive industrial and traffic activities, the Kao-Ping area has the poorest air quality in Taiwan − either increased ground-level concentrations of particulate matter (PM) or ozone (O3) associated with unfavorable meteorological conditions − particularly between late fall and mid-spring The temporal and spatial characterization of suspended particles in the Kao-Ping area was analyzed by using TAPM (air quality model) and CMB (receptor model) to understand the contributions of the major emission sources. Estimations using the TAPM model suggest that point-source emissions were the predominant contributors (about 49.1%) to PM10 concentrations at Hsiung-Kong industrial site in Kaohsiung City, followed by area sources (approximately 35.0%) and neighboring transport (7.8%). Because Ping-Tung City (urban) and Chao-Chou town (rural) are located downwind of Kaohsiung City when north or northeasterly winds prevail, the two sites also experience severe pollution events despite the lack of industrial sources; neighboring transport contributed roughly 39.1% to PM10 concentrations at Ping-Tung and 48.7% at Chao-Chou. Results of CMB (chemical mass balance) modeling show that the main contributors to PM2.5 mass are vehicle exhaust (gasoline vehicle emission: 43% and diesel vehicle emission: 17% at Hsiung-Kong; gasoline vehicle emission: 45% and diesel vehicle emission: 19% at Ping-Tung; gasoline vehicle emission: 12% and diesel vehicle emission: 29% at Chao-Chou). And the main contribution to PM2.5-10 mass is the paved road emission (Hsiung-Kong: 40%; Ping-Tung: 48%; Chao-Chou: 50%). It is recommended that air quality model is an appropriate tool to large area and receptor model is more suitable to specific point to identify emission sources by the results in this study.
4

An air quality baseline assessment for the Vaal Airshed in South Africa

Thomas, Rene Georgeinna 05 October 2009 (has links)
The Vaal Triangle is renowned for its highly industrialised activities. With the addition of domestic fuel burning, vehicle exhaust, mining and agricultural activities, the Vaal Airshed has become highly polluted. The concerns of the elevated concentrations in the area were raised by the Department of Environmental Affairs and Tourism (DEAT) when the Vaal Region was declared the first priority area on 21 April 2006. The basis for this declaration includes: areas that exceed or may exceed air quality standards, areas associated with significant air quality impacts and areas requiring specific air quality management actions to rectify the situation. The purpose of this study is to determine the Status Quo of the Vaal Airshed. The emissions inventory for the study area includes industrial operations, mining activities, domestic fuel burning and vehicle tailpipe emissions along major national and regional routes. Priority pollutants (i.e. sulphur dioxide, nitrogen dioxide and inhalable particulate matter) are assessed with the aid of the US Environmental Protection Agency approved CALPUFF modelling suite, a non-steady-state Lagrangian Gaussian puff dispersion model. From the dispersion simulations an air quality impact assessment is undertaken. The major findings of the air quality assessment indicate that particulate concentrations are elevated over most areas of the Vaal Airshed, particularly in residential areas where domestic coal burning occurs and areas neighbouring major industrial operations. Similarly, elevated sulphur dioxide concentrations occur over industrial and domestic coal burning areas. Elevated nitrogen dioxide concentrations have a regional impact over the Vaal Airshed. Priority areas are identified based on the predicted ambient air concentrations from the priority pollutants and exposure potential. Source contributions are investigated based on the extent of their emissions and basis of impacts. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Geography, Geoinformatics and Meteorology / Unrestricted
5

Direct and indirect ecological consequences of human activities in urban and native ecosystems

January 2014 (has links)
abstract: Though cities occupy only a small percentage of Earth's terrestrial surface, humans concentrated in urban areas impact ecosystems at local, regional and global scales. I examined the direct and indirect ecological outcomes of human activities on both managed landscapes and protected native ecosystems in and around cities. First, I used highly managed residential yards, which compose nearly half of the heterogeneous urban land area, as a model system to examine the ecological effects of people's management choices and the social drivers of those decisions. I found that a complex set of individual and institutional social characteristics drives people's decisions, which in turn affect ecological structure and function across scales from yards to cities. This work demonstrates the link between individuals' decision-making and ecosystem service provisioning in highly managed urban ecosystems. Second, I examined the distribution of urban-generated air pollutants and their complex ecological outcomes in protected native ecosystems. Atmospheric carbon dioxide (CO<sub>2</sub>), reactive nitrogen (N), and ozone (O<sub>3</sub>) are elevated near human activities and act as both resources and stressors to primary producers, but little is known about their co-occurring distribution or combined impacts on ecosystems. I investigated the urban "ecological airshed," including the spatial and temporal extent of N deposition, as well as CO<sub>2</sub> and O<sub>3</sub> concentrations in native preserves in Phoenix, Arizona and the outlying Sonoran Desert. I found elevated concentrations of ecologically relevant pollutants co-occur in both urban and remote native lands at levels that are likely to affect ecosystem structure and function. Finally, I tested the combined effects of CO<sub>2</sub>, N, and O<sub>3</sub> on the dominant native and non-native herbaceous desert species in a multi-factor dose-response greenhouse experiment. Under current and predicted future air quality conditions, the non-native species (<italic>Schismus arabicus</italic>) had net positive growth despite physiological stress under high O<sub>3</sub> concentrations. In contrast, the native species (<italic>Pectocarya recurvata</italic>) was more sensitive to O<sub>3</sub> and, unlike the non-native species, did not benefit from the protective role of CO<sub>2</sub>. These results highlight the vulnerability of native ecosystems to current and future air pollution over the long term. Together, my research provides empirical evidence for future policies addressing multiple stressors in urban managed and native landscapes. / Dissertation/Thesis / Doctoral Dissertation Plant Biology 2014
6

Proximity to Potential Sources and Mountain Cold-trapping of Semi-volatile Organic Contaminants

Westgate, John Norman 13 August 2013 (has links)
If sufficiently persistent, semi-volatile organic contaminants (SVOCs) can travel long distances through the atmosphere from their points of release and become concentrated in cold, remote regions. As air is sampled for SVOCs to establish both their presence and the success of emission reduction efforts, it becomes helpful to determine sampling site proximity to sources and the origin of the sampled air masses. Comparing three increasingly sophisticated methods for quantifying source proximity of sampling locations, it was judged necessary to account for the actual history of the sampled air through construction of an airshed, especially if wind is highly directional and population distribution is very non-uniform. The airshed concept was improved upon by introducing a ‘geodesic’ grid of equally spaced cells, rather than a simple latitude/longitude grid, to avoid distortion near Earth’s poles and to allow for the comparison of airshed shapes. Assuming that a perfectly round airshed reveals no information about sources allows the significance of each cell of an airshed to be judged based on its departure from roundness. Combining air-mass histories with a 2 year-long series of SVOC air concentrations at Little Fox Lake in Canada’s Yukon Territory did not identify distinct source regions for most analytes, although γ-hexachlorocyclohexane appears to originate broadly in north-eastern Russia and/or Alaska. Based on this remoteness from sources, the site is judged to be well suited to monitor changes in the hemispheric background concentrations of SVOCs. A model-based exploration revealed wet-gaseous deposition as the dominant process responsible for cold-trapping SVOCs in mountain soils. Such cold trapping is particularly effective if precipitation rate increases with altitude and if temperature differences along the mountain are large. Considerable sensitivity of the modeled extent of cold-trapping to parameters as diverse as scale, mean temperature, atmospheric particle concentration and time relative to emission maxima is consistent with the wide variety of observed enrichment behaviour. Concentration gradients of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in air and soil measured on four Western Canadian mountains with variable distance from sources revealed source proximity as the main driver of concentrations at both the whole-mountain scale and along individual mountain transects.
7

Proximity to Potential Sources and Mountain Cold-trapping of Semi-volatile Organic Contaminants

Westgate, John Norman 13 August 2013 (has links)
If sufficiently persistent, semi-volatile organic contaminants (SVOCs) can travel long distances through the atmosphere from their points of release and become concentrated in cold, remote regions. As air is sampled for SVOCs to establish both their presence and the success of emission reduction efforts, it becomes helpful to determine sampling site proximity to sources and the origin of the sampled air masses. Comparing three increasingly sophisticated methods for quantifying source proximity of sampling locations, it was judged necessary to account for the actual history of the sampled air through construction of an airshed, especially if wind is highly directional and population distribution is very non-uniform. The airshed concept was improved upon by introducing a ‘geodesic’ grid of equally spaced cells, rather than a simple latitude/longitude grid, to avoid distortion near Earth’s poles and to allow for the comparison of airshed shapes. Assuming that a perfectly round airshed reveals no information about sources allows the significance of each cell of an airshed to be judged based on its departure from roundness. Combining air-mass histories with a 2 year-long series of SVOC air concentrations at Little Fox Lake in Canada’s Yukon Territory did not identify distinct source regions for most analytes, although γ-hexachlorocyclohexane appears to originate broadly in north-eastern Russia and/or Alaska. Based on this remoteness from sources, the site is judged to be well suited to monitor changes in the hemispheric background concentrations of SVOCs. A model-based exploration revealed wet-gaseous deposition as the dominant process responsible for cold-trapping SVOCs in mountain soils. Such cold trapping is particularly effective if precipitation rate increases with altitude and if temperature differences along the mountain are large. Considerable sensitivity of the modeled extent of cold-trapping to parameters as diverse as scale, mean temperature, atmospheric particle concentration and time relative to emission maxima is consistent with the wide variety of observed enrichment behaviour. Concentration gradients of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in air and soil measured on four Western Canadian mountains with variable distance from sources revealed source proximity as the main driver of concentrations at both the whole-mountain scale and along individual mountain transects.

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