Matching Items (3)
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- All Subjects: Air
- Genre: Academic theses
- Creators: Alum, Absar
- Creators: Forzani, Erica S.
- Member of: ASU Electronic Theses and Dissertations
- Status: Published
Description
Air pollution is a serious problem in most urban areas around the world, which has a number of negative ecological and human health impacts. As a result, it's vitally important to detect and characterize air pollutants to protect the health of the urban environment and our citizens. An important early step in this process is ensuring that the air pollution monitoring network is properly designed to capture the patterns of pollution and that all social demographics in the urban population are represented. An important aspect in characterizing air pollution patterns is scale in space and time which, along with pattern and process relationships, is a key subject in the field of landscape ecology. Thus, using multiple landscape ecological methods, this dissertation research begins by characterizing and quantifying the multi-scalar patterns of ozone (O3) and particulate matter (PM10) in the Phoenix, Arizona, metropolitan region. Results showed that pollution patterns are scale-dependent, O3 is a regionally-scaled pollutant at longer temporal scales, and PM10 is a locally-scaled pollutant with patterns sensitive to season. Next, this dissertation examines the monitoring network within Maricopa County. Using a novel multiscale indicator-based approach, the adequacy of the network was quantified by integrating inputs from various academic and government stakeholders. Furthermore, deficiencies were spatially defined and recommendations were made on how to strengthen the design of the network. A sustainability ranking system also provided new insight into the strengths and weaknesses of the network. Lastly, the study addresses the question of whether distinct social groups were experiencing inequitable exposure to pollutants - a key issue of distributive environmental injustice. A novel interdisciplinary method using multi-scalar ambient pollution data and hierarchical multiple regression models revealed environmental inequities between air pollutants and race, ethnicity, age, and socioeconomic classes. The results indicate that changing the scale of the analysis can change the equitable relationship between pollution and demographics. The scientific findings of the scale-dependent relationships among air pollution patterns, network design, and population demographics, brought to light through this study, can help policymakers make informed decisions for protecting the human health and the urban environment in the Phoenix metropolitan region and beyond.
ContributorsPope, Ronald L (Author) / Wu, Jianguo (Thesis advisor) / Boone, Christopher G. (Committee member) / Brazel, Anthony J. (Committee member) / Forzani, Erica S. (Committee member) / Fraser, Matthew P. (Committee member) / Arizona State University (Publisher)
Created2014
Description
Mexico City has an ongoing air pollution issue that negatively affects its citizens and surroundings with current structural disconnections preventing the city from improving its overall air quality. Thematic methodological analysis reveals current obstacles and barriers, as well as variables contributing to this persistent problem. A historical background reveals current programs and policies implemented to improve Mexico’s City air quality. Mexico City’s current systems, infrastructure, and policies are inadequate and ineffective. There is a lack of appropriate regulation on other modes of transportation, and the current government system fails to identify how the class disparity in the city and lack of adequate education are contributing to this ongoing problem. Education and adequate public awareness can potentially aid the fight against air pollution in the Metropolitan City.
ContributorsGarcia, Lucero (Author) / Duarte, Marisa E. (Thesis advisor) / Arzubiaga, Angela (Committee member) / Richter, Jennifer (Committee member) / Arizona State University (Publisher)
Created2018
Description
Since its first report in 1976, many outbreaks linked to Legionella have been reported in the world. These outbreaks are a public health concern because of legionellosis, which is found in two forms, Pontiac fever and Legionnaires disease. Legionnaires disease is a type of pneumonia responsible for the majority of the illness in the reported outbreaks of legionellosis. This study consists of an extensive literature review and experimental work on the aerosolization and UV inactivation of E.coli and Legionella under laboratory conditions. The literature review summarizes Legionella general information, occurrence, environmental conditions for its survival, transmission to human, collection and detection methodologies and Legionella disinfection in air and during water treatment processes.
E. coli was used as an surrogate for Legionella in experimentation due to their similar bacterial properties such as size, gram-negative rod-shaped, un-encapsulated and non-spore-forming bacterial cells. The accessibility and non-pathogenicity of E. coli also served as factors for the substitution.
Three methods of bacterial aerosolization were examined, these included an electric spray gun, an air spray gun and a hand-held spray bottle. A set of experiments were performed to examine E. coli aerosolization and transport in the aerosolization chamber (an air tight box) placed in a Biological Safety Cabinet. Spiked sample was sprayed through the opening from one side of the aerosolization chamber using the selected aerosolization methods. The air sampler was placed at the other side to collect 100 L air sample from the aerosolization chamber. A Tryptic Soy Agar plate was placed inside the air sampler to collect and subsequently culture E. coli cells from air. Results showed that the air spray gun has the best capability of aerosolizing bacteria cells under all the conditions examined in this study compared to the other two spray methods. In this study, we provide a practical and efficient method of bacterial aerosolization technique for microbial dispersion in air. The suggested method can be used in future research for microbial dispersion and transmission studies.
A set of experiments were performed to examine UV inactivation of E. coli and Legionella cells in air. Spiked samples were sprayed through the opening from one side of the aerosolization chamber using the air spray gun. A UV-C germicidal lamp inside the Biological Safety Cabinet was turned on after each spray. The air samples were collected as previously described. The application of UV-C for the inactivation of bacterial cells resulted in removing aerosolized E. coli and Legionella cells in air. A 1 log reduction was achieved with 5 seconds UV exposure time while 10 seconds UV exposure resulted in a 2 log bacterial reduction for both bacteria. This study shows the applicability of UV inactivation of pathogenic bacterial cells in air by short UV exposure time. This method may be applicable for the inactivation of Legionella in air ducts by installing germicidal UV lamps for protecting susceptible populations in certain indoor settings such as nursing homes or other community rooms.
E. coli was used as an surrogate for Legionella in experimentation due to their similar bacterial properties such as size, gram-negative rod-shaped, un-encapsulated and non-spore-forming bacterial cells. The accessibility and non-pathogenicity of E. coli also served as factors for the substitution.
Three methods of bacterial aerosolization were examined, these included an electric spray gun, an air spray gun and a hand-held spray bottle. A set of experiments were performed to examine E. coli aerosolization and transport in the aerosolization chamber (an air tight box) placed in a Biological Safety Cabinet. Spiked sample was sprayed through the opening from one side of the aerosolization chamber using the selected aerosolization methods. The air sampler was placed at the other side to collect 100 L air sample from the aerosolization chamber. A Tryptic Soy Agar plate was placed inside the air sampler to collect and subsequently culture E. coli cells from air. Results showed that the air spray gun has the best capability of aerosolizing bacteria cells under all the conditions examined in this study compared to the other two spray methods. In this study, we provide a practical and efficient method of bacterial aerosolization technique for microbial dispersion in air. The suggested method can be used in future research for microbial dispersion and transmission studies.
A set of experiments were performed to examine UV inactivation of E. coli and Legionella cells in air. Spiked samples were sprayed through the opening from one side of the aerosolization chamber using the air spray gun. A UV-C germicidal lamp inside the Biological Safety Cabinet was turned on after each spray. The air samples were collected as previously described. The application of UV-C for the inactivation of bacterial cells resulted in removing aerosolized E. coli and Legionella cells in air. A 1 log reduction was achieved with 5 seconds UV exposure time while 10 seconds UV exposure resulted in a 2 log bacterial reduction for both bacteria. This study shows the applicability of UV inactivation of pathogenic bacterial cells in air by short UV exposure time. This method may be applicable for the inactivation of Legionella in air ducts by installing germicidal UV lamps for protecting susceptible populations in certain indoor settings such as nursing homes or other community rooms.
ContributorsYao, Wei (Author) / Abbaszadegan, Morteza (Thesis advisor) / Fox, Peter (Committee member) / Alum, Absar (Committee member) / Arizona State University (Publisher)
Created2015