• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 116
  • 9
  • 4
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 167
  • 167
  • 167
  • 52
  • 46
  • 30
  • 22
  • 20
  • 20
  • 17
  • 16
  • 14
  • 14
  • 14
  • 13
  • 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.
151

Particulate Modeling and Control Strategy of Atlanta, Georgia

Park, Sun-kyoung 23 November 2005 (has links)
Particles reduce visibility, change climate, and affect human health. In 1997, the National Ambient Air Quality Standard (NAAQS) for PM2.5 (particles less than 2.5 mm) was promulgated. The annual mean PM2.5 mass concentrations in Atlanta, Georgia exceed the standard, and control is needed. The first goal of this study is to develop the control strategies of PM2.5 in Atlanta, Georgia. Based on the statistical analysis of measured data, from 22% to 40% of emission reductions are required to meet the NAAQS at 95% CI. The estimated control levels can be tested using the Community Multiscale Air Quality (CMAQ) model to better assess if the proposed levels will achieve sufficient reduction in PM2.5. The second goal of this study is to analyze various uncertainties residing in CMAQ. For the model to be used in such applications with confidence, it needs to be evaluated. The model performance is calculated by the relative agreement between volume-averaged predictions and point measurements. Up to 14% of the model error for PM2.5 mass is due to the different spatial scales of the two values. CMAQ predicts PM2.5 mass concentrations reasonably well, but CMAQ significantly underestimates PM2.5 number concentrations. Causes of the underestimation include that assumed inaccurate particle density and particle size of the primary emissions in CMAQ, in addition to the expression of the particle size with three lognormal distributions. Also, the strength and limitations of CMAQ in performing PM2.5 source apportionment are compared with those of the Chemical Mass Balance with Molecular Markers. Finally, the accuracy of emissions, one of the important inputs of CMAQ, is evaluated by the inverse modeling. Results show that base level emissions for CO and SO2 sources are relatively accurate, whereas NH3, NOx, PEC and PMFINE emissions are overestimated. The emission adjustment for POA and VOC emissions is significantly different among regions.
152

Three essays in program evaluation the case of Atlanta inspection and maintenance program /

Supnithadnaporn, Anupit. January 2009 (has links)
Thesis (Ph.D)--Public Policy, Georgia Institute of Technology, 2009. / Committee Chair: Noonan, Douglas; Committee Member: Castillo, Marco; Committee Member: Chang, Michael; Committee Member: Cozzens, Susan; Committee Member: Rodgers, Michael. Part of the SMARTech Electronic Thesis and Dissertation Collection.
153

Industrial perspectives on the implementation of the Air Quality Act (AQA) (Act No. 39 of 2004)

Barnwell, Liesl. January 2009 (has links)
The Air Quality Act (AQA) Act No.39 of 2004 promulgated in 2004 follows the outdated Atmospheric Pollution Prevention Act (APPA) (Act No.45 of 1965). The legislative approach shifted from a source- based, end of pipe, command and control, guideline principle to ambient air quality management and improvement of compliance to standards through a consultative process. The AQA’s management framework incorporates a co-operative and integrated approach with government, communities and polluters to look at the holistic management of ambient air quality and the identified roles and responsibilities for all stakeholders. The AQA branched from the National Environmental Management Act (NEMA) 107 of 1998, which is the first piece of legislation formalizing the principles of the Integrated Pollution Waste Management (IPWM) Policy published in 2000 and the Bill of Rights. Government and Industry have a role to play in the implementation of the AQA. Government’s role covers the management and enforcement aspects, whilst industries’ role includes the management of air emissions and compliance reporting to improve the overall ambient air quality. The AQA’s industrial requirements range from compliance and reporting by ensuring emission licenses are in place, compliance with standards set by different spheres of government and the management of these emissions. The management of these requirements includes understanding the legislation, its implications and the provision of other financial, human and technological resources. Industry needs to consider the impacts of these legislative changes and how it may impact business as a whole. The aim of this study is to analyze the industrial perspectives of the AQA and its implementation through the use of a questionnaire. Open-ended questionnaires were administered to a total of forty industrial companies in the chemical, petrochemical, energy and mining sectors in the Gauteng, North West and Durban industrial areas. Industries were identified as those which have scheduled process certificates or companies that will be impacted by the impending changes as a result of the AQA. The overall outcome of the industrial responses revealed poor general knowledge of the principles, purpose and the reasons for the transition from APPA to AQA. Few industries had insight into the type of challenges they may face from the AQA’s listed control measures and the control measures that would apply to their particular industry. There is a general concern surrounding the government’s lack of support and the essential enforcement that is required to ensure ambient air quality compliance. These challenges and recommendations are discussed in the thesis. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2009.
154

Air pollution population exposure evaluation in the Vaal Triangle using GIS

Liebenberg, Hanlie 22 August 2012 (has links)
M.Sc. / The evaluation of population exposure to air pollution is a fundamental reason for management and control of regional air quality. The purpose of this study was to determine the exposure of the local population to PM-10 emissions from sources within the Vaal Triangle using a Geographic Information System (GIS). The emission inventory compiled by van Nierop for the calendar year of 1992 (van Nierop, 1994) was used as input data for these calculations. The Industrial Source Complex Short Term Model (ISCST) was applied for dispersion calculations of annual PM-10 emissions. The ReGIS package was applied to determine the applicability of GIS as a management tool. Annual average PM-10 concentration contours were calculated for the different air pollution source groups within the Vaal Triangle. The combined source group resulted in the highest population exposure from annual average PM-10 concentrations. Population exposure from high- (> 200 m), medium- (10 to 200 m) and low- (< 10 m) elevation air pollution source groups were determined. The medium-elevation source group resulted in high population exposure followed by the low-elevation source group. The high-elevation source group had very low population exposure as a result. The population exposures from all the industrial sources within the Vaal Triangle were calculated and found to be very high. Annual average PM-10 concentrations from domestic fuel combustion sources were surprisingly low, resulting in low population exposure. ReGIS was found to be inadequate for the task and is not recommended for further use. Despite this, GIS was found to be a powerful decision-making tool and other GIS software packages should be explored for future research.
155

Emerging Trends in Greenhouse Gas Thresholds of Significance for Use Under the California Environmental Quality Act

Mathison, Nancy E 01 December 2010 (has links) (PDF)
This study determined the state of the practice and emerging trends in developing greenhouse gas (GHG) thresholds of significance for use under the California Environmental Policy Act (CEQA). To describe the adopted, proposed or considered approaches for developing thresholds of significance by air districts and the thought processes behind these decisions, information was obtained through surveys and phone interviews from twelve employees of air districts in California, State agencies, and consultants that are considered experts on this issue. The results of this study include a comparison matrix of the approaches of the three air districts that have adopted or proposed GHG thresholds of significance, and identification of the common themes from air districts’ responses that do not have adopted or proposed thresholds. While the development of GHG thresholds of significance is an evolving practice, emerging trends in this practice were identified. These trends include providing flexibility in options, an emphasis on programmatic approaches and a preference of including bright-line thresholds and efficiency thresholds. Furthermore, this paper concludes that while the three air districts that have proposed or adopted thresholds have laid the groundwork for other districts, some of the approaches or the thresholds themselves may not be easily transferable to other districts based on regional differences. This research provides insight into how GHG emissions might be addressed in CEQA documents throughout the State.
156

Nixon and the environment: clean air, automobiles and reelection

Unknown Date (has links)
the decades after World War II the United States became the most prosperous nation in the world. Yet, that prosperity and growth had a negative impact on the environmental quality of the nation. By the mid 1960s there was a rise in concern over environmental issues in the American public. Consequently, President Richard M. Nixon in his determination to give the American people what they sought decided to enact policies to bring the environmental crisis to an end. Among the environmental policies of the Nixon Administration was the Clean Air Act of 1970, a highly controversial piece of legislation that placed tough regulations on the automobile industry. Due to the significant role of the auto industry in the American economy, and Nixon's concerns over reelection, there were two major shifts in business/government relations during this era. The first one was characterized by determination to protect the environment with little attention to complaints from the industry. The second one was about protecting the profitability of the industry while giving little attention to environmental problems. / by Erwin Mauricio Escobar. / Thesis (M.A.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
157

Pedestrianization in Hong Kong: its impacts on air quality and human response.

January 2001 (has links)
Kam Wai-ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 153-162). / Abstracts in English and Chinese ; questionnaire in Chinese. / List of Tables --- p.x / List of Figures --- p.xiii / List of Abbreviation --- p.xvi / Chapter Chapter One --- Introduction --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- The Research Problems --- p.2 / Chapter 1.3 --- Objectives of the Study --- p.4 / Chapter 1.4 --- Study Area --- p.4 / Chapter 1.5 --- Significance of the Study --- p.8 / Chapter 1.6 --- Organization of Thesis --- p.9 / Chapter Chapter Two --- Literature Review --- p.11 / Chapter 2.1 --- Pedestrianization: Basic Ideas and History --- p.11 / Chapter 2.1.1 --- Definition of Pedestrianization --- p.11 / Chapter 2.1.2 --- Motivation of pedestrianization --- p.13 / Chapter 2.1.3 --- Learning from the Development of Pedestrianization in Other Cities --- p.15 / Chapter 2.1.4 --- Impacts of Pedestrianization on Environment --- p.19 / Chapter 2.2 --- Pedestrianization in Hong Kong --- p.21 / Chapter 2.2.1 --- Development --- p.21 / Chapter 2.2.2 --- Ways for Successful Pedestrianization in Hong Kong --- p.22 / Chapter 2.3 --- Human Perception and Response on Air Pollution and Pedestrianization --- p.24 / Chapter 2.3.1 --- Introduction of Human Perception --- p.24 / Chapter 2.3.2 --- Human Perception of Air Pollution --- p.27 / Chapter 2.3.3 --- Changes of Human Perception in Response to the Changes of Environmental Quality After Pedestrianization --- p.31 / Chapter Chapter Three --- Methodology --- p.34 / Chapter 3.1 --- Research Design --- p.34 / Chapter 3.2 --- BACIPR Approach --- p.35 / Chapter 3.3 --- Objective Assessment of the influence of pedestrianization on air quality --- p.38 / Chapter 3.3.1 --- Model Prediction --- p.39 / Chapter 3.3.2 --- Physical Measurement of Particulates --- p.46 / Chapter 3.4 --- Subjective Assessment: Human Perception of Roadside Air Pollution --- p.56 / Chapter 3.4.1 --- Guidelines Used for Subjective Assessment --- p.57 / Chapter 3.4.2 --- Development of the Questionnaire --- p.58 / Chapter 3.4.3 --- Statistical Analysis --- p.59 / Chapter Chapter Four --- Model Simulation of the Effect of Pedestrianization on Air Quality --- p.61 / Chapter 4.1 --- Introduction --- p.61 / Chapter 4.2 --- Air Quality in Causeway Bay Before Pedestrianization --- p.64 / Chapter 4.2.1 --- Overall Spatial Variation of Air Quality --- p.64 / Chapter 4.2.2 --- Respiratory Suspended Particulate (RSP) --- p.67 / Chapter 4.2.3 --- Nitrogen Dioxide (N02) --- p.68 / Chapter 4.2.4 --- Carbon Monoxide (CO) --- p.69 / Chapter 4.3 --- Air Quality in Causeway Bay After Pedestrianization --- p.70 / Chapter 4.3.1 --- Overall Spatial Variation of Air Quality --- p.70 / Chapter 4.3.2 --- Respiratory Suspended Particulate (RSP) --- p.70 / Chapter 4.3.3 --- Nitrogen Dioxide (N02) --- p.73 / Chapter 4.3.4 --- Carbon Monoxide (CO) --- p.75 / Chapter 4.3.5 --- Effect of Government's Pedestrianization Scheme in Improving Air Quality --- p.77 / Chapter 4.4 --- Air Quality Impact of Pedestrianization in Single Street --- p.77 / Chapter 4.4.1 --- RSP Concentration in Russell Street Section Before Pedestrianization --- p.78 / Chapter 4.4.2 --- RSP Concentration in Russell Street Section After Pedestrianization --- p.81 / Chapter 4.5 --- Summary and Conclusion --- p.83 / Chapter Chapter Five --- Measurement of Particulate Pollution in Causeway Bay --- p.84 / Chapter 5.1 --- Change in Particulate Pollution After Pedestrianization in Russell Street --- p.86 / Chapter 5.1.1 --- Overall Changes in Particulate Pollution after Pedestrianization --- p.86 / Chapter 5.1.2 --- Changes in Particulate Pollution after Pedestrianization under Different Weather Conditions --- p.87 / Chapter 5.1.2.1 --- Effects of Pedestrianization on Fine Day --- p.88 / Chapter 5.1.2.2 --- Effects of Pedestrianization on Rainy Days --- p.89 / Chapter 5.1.3 --- Changes of Particulate Pollution after Pedestrianization under Different Traffic Flow Conditions --- p.90 / Chapter 5.1.3.1 --- Effects of Pedestrianization during Peak Hours --- p.91 / Chapter 5.1.3.2 --- Effects of Pedestrianization during Non-Peak Hours --- p.92 / Chapter 5.1.4 --- Changes in Particulate Pollution As a result of Pedestrianization on Different Days of the Week --- p.93 / Chapter 5.1.4.1 --- Effects of Pedestrianization on Weekdays --- p.94 / Chapter 5.1.4.2 --- Effects of Pedestrianization on Non-Weekdays --- p.94 / Chapter 5.1.5 --- Change in PM 10 I/C ratio After Pedestrianization --- p.95 / Chapter 5.2 --- Variations in Particulate Pollution Characteristics Due to Different Pedestrianization Street Designs --- p.96 / Chapter 5.2.1 --- General Contrasts between an Open and Semi-enclosed Street --- p.97 / Chapter 5.2.2 --- Seasonal Effect on Particulate Pollution in Jardine's Crescent and in Its Control Street --- p.97 / Chapter 5.2.3 --- Climatic Effects on Particulate Pollution --- p.101 / Chapter 5.2.4 --- Effects of Traffic Conditions on Particulate Pollution Pattern in Jardine's Crescent and in Its Control Street --- p.102 / Chapter 5.2.5 --- Effects of Day of the Week on Particulate Pollution --- p.104 / Chapter 5.3 --- The Variation of Particulate Pollution in Causeway Bay --- p.105 / Chapter 5.3.1 --- Spatial Variation --- p.105 / Chapter 5.3.2 --- Seasonal Variation --- p.108 / Chapter 5.3.3 --- Rain as a Cleaning Agent --- p.111 / Chapter 5.4 --- Summary and Conclusion --- p.112 / Chapter Chapter Six --- Pedestrianization and Perception of Air Quality --- p.113 / Chapter 6.1 --- Introduction --- p.113 / Chapter 6.2 --- Effect of Pedestrianization in Improving the Perceived Air Quality --- p.115 / Chapter 6.2.1 --- Overall Changes of PAQ after Pedestrianization --- p.115 / Chapter 6.2.2 --- Changes in Perceived Air Quality As a Result of Pedestrianization --- p.118 / Chapter 6.2.2.1 --- Correlation between PAQ and AQ --- p.118 / Chapter 6.2.2.2 --- Difference in Dose-Response Relationships before and after Pedestrianization --- p.120 / Chapter 6.2.3 --- Summary of Findings on Human Perception --- p.136 / Chapter 6.3 --- Aspects of Pedestrianization Which Improve Perceived Air Quality --- p.136 / Chapter 6.3.1 --- Behavior Constraint Model --- p.137 / Chapter 6.3.2 --- Environmental Stress Model --- p.139 / Chapter 6.3.3 --- Perception of Air Pollution Through Smell and Vision --- p.141 / Chapter 6.4 --- Summary and Conclusion --- p.144 / Chapter Chapter Seven --- Conclusion --- p.146 / Chapter 7.1 --- Summary of Findings --- p.146 / Chapter 7.1.1 --- Model Simulated Air Pollution Levels in Causeway Bay and Possible Effects of the Government Pedestrianization Scheme --- p.147 / Chapter 7.1.2 --- Changes in the Pattern and Characteristics of Particulate Pollution after Pedestrianization --- p.148 / Chapter 7.1.3 --- Effects of Pedestrianization on Human Perception of Air Quality --- p.149 / Chapter 7.2 --- Discussion of Findings --- p.151 / References --- p.153 / Appendix A --- p.163
158

Air pollution impacts as indicated by roadside air quality monitoring stations

江顯其, Kong, Hin-kee. January 1999 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
159

Characterization and source apportionment of ambient PM2.5 in Atlanta, Georgia: on-road emission, biomass burning and SOA impact

Yan, Bo 20 August 2009 (has links)
Characterization and Source Apportionment of Ambient PM2.5 in Atlanta, Georgia: On-Road Emission, Biomass Burning and SOA Impact Bo Yan 260 Pages Directed by Drs. Armistead G. Russell and Mei Zheng Various airborne PM2.5 samples were collected in the metropolitan Atlanta and surrounding areas, which are directly impacted or dominated by on-road mobile and other typical urban emissions, regional transport sources, prescribed burning plumes, wildfire plumes, as well as secondary sources with anthropogenic and biogenic nature in origin. Detailed PM2.5 chemical speciation was conducted including over one hundred of GC/MS-quantified organic compounds, organic carbon (OC), water-soluble organic carbon (WSOC), elemental carbon (EC), ionic species, and tens of trace metals. Day-night, seasonal and spatial variations of PM2.5 characterization were also studied. Contributions of PM2.5 major sources were identified quantitatively through the receptor source apportionment models. These modeling results, especially on-road mobile source contributions and secondary organic carbon (SOC) were assessed by multiple approaches. Furthermore, new season- and location-specific source profiles were developed in this research to reflect real-world and representative local emission characterizations of on-road mobile sources, aged prescribed burning plumes, and wildfire plumes. Secondary organic aerosol (SOA), a major component of PM2.5 in the summer, was also explored for sources and contributions.
160

Development of selected sulphur compounds and oxygenated volatile organic compounds reference gas mixtures for air quality monitoring

Leshabane, Nompumelelo 05 1900 (has links)
Highly accurate analysis for the quantification of sulphur compounds and oxygenated volatile organic compounds are crucial for the adherence of the legislation in different environmental sectors. The sulphur compounds and oxygenated volatile organic compounds measurements are challenging, due to various factors such as molecules being adsorbed on the inner surfaces of cylinders. It is therefore important to produce accurate and reliable reference gas mixtures with mole fraction at ambient levels for the air quality monitoring and field of gas sensing in South Africa. The challenges in producing sulphur compounds and oxygenated volatile organic compounds reference gas mixtures are that the overall process from gravimetric preparation steps until the comparison analysis process and the stability of mixture in the gas cylinder, results in the large measurement uncertainties. In order to produce reference gas mixtures of the highest level, three important steps are followed: purity assessment of starting material, gravimetric preparation, and verification/validation of prepared gas mixtures. The purity analysis of high purity starting materials was determined using gas chromatography coupled with various detectors and Karl Fischer for determination of moisture content in high purity chemicals. The sulphur compounds and oxygenated volatile organic compounds to be developed in this study were hydrogen sulphide, sulphur dioxide, acetone, methanol, ethanol, isopropanol, and n-butanol. These components were produced following the International Organisation for Standardisation documents at mole fraction of 10 µmol/mol for sulphur compounds and 5 µmol/mol for oxygenated volatile organic compounds. The preparation of sulphur compounds reference gas mixtures was done with a static gravimetric method using a direct method where a target component was transferred directly into the cylinder. The preparation of oxygenated volatile organic compounds used an indirect method whereby a target liquid component from high purity chemicals was transferred into a cylinder using a gas-tight syringe.The comparison between the reference gas mixtures was validated using Non-Dispersive Ultra-Violet analysers (NDUV), gas chromatograph coupled with pulsed discharge helium ionisation detector (GC-PDHID, UV fluorescence analysers for sulphur compounds and gas chromatograph coupled with flame ionisation detector (GC-FID) for the oxygenated volatile organic compounds. A multi-point calibration method was used to analyse sulphur dioxide and hydrogen sulphide on the NDUV analyser, and the single-point calibration method was used for analysis on the gas chromatography and UV fluorescence where a sample mixture is analysed against a reference mixture with a similar mole fraction. The statistical data considered during analysis included calculation of the instrument drift and percentage relative standard deviation to check measurements repeatability, reliability, and measurement uncertainty. The gravimetric results of prepared sulphur compounds at 10 µmol/mol gave a percentage relative expanded uncertainty of 0.041 % REU for hydrogen sulphide, 0.12 % REU for sulphur dioxide. The gravimetric results of prepared oxygenated volatile organic compounds at 5 µmol/mol showed a percentage relative expanded uncertainty 0.068 to 0.35 % REU for isopropanol and ethanol respectively and less than 2.4 % REU for multi component of oxygenated volatile organic compounds. Finally, the primary standard gas mixtures of sulphur compounds and oxygenated volatile organic compounds were developed with the highest metrological measurement uncertainty level of (k=2). / Environmental Sciences / M. Sc. (Environmental Sciences)

Page generated in 0.6309 seconds