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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.
1021

Monitoring nejonizujućeg zračenja, zagađujućih materija i toplotnih indeksa u regionu Vojvodine / Monitoring of the non-ionizing radiation, air pollution and heat indexes in Vojvodina region

Malinović Milićević Slavica 19 November 2012 (has links)
<p>Predmet istraživanja ove disertacije je monitoring i analiza ultraljubičastog zračenja, toplotnih indeksa i zagađujućih materija u vazduhu većih naselja na teritoriji Vojvodine. Cilj istraživanja je da se prostornom i vremenskom analizom posmatranih parametara dođe do &scaron;to optimalnijih saznanja o stanju kvaliteta životne sredine na području Vojvodine kao i stvaranje jedinstvene baze podataka koja će služiti za buduća istraživanja. U radu je ispitan odnos između sunčevog globalnog i UV zračenja, izvedena i verifikovana empirijska jednačina za procenu dnevnih suma UV-B zračenja u osam naselja za period 1981-2008, analizirane koncentracije pet zagađujućih materija u sedam naselja za period 2001-2008. godina i analizirani toplotni indeksi u sedam naselja u periodu od 1992. do 2008. Analiza pokazuje da rekonstruisane vrednosti dnevnih suma UV-B zračenja i srednji godi&scaron;nji toplotni indeksi u svim naseljima pokazuju tendenciju rasta i da dominantan uticaj na kvalitet vazduha u naseljima Vojvodine imaju čestice. Napravljena je jedinstvena baze podataka sa vrednostima koncentracija zagađivača vazduha, toplotnih indeksa, UV i globalnog zračenja.</p> / <p>This study analyzes UV radiation, heat indexes and air pollution in town in Vojvodina region. Objective of the thesis is to provide scientific facts about environmental quality in Vojvodina, as well as, to generate unique data base for the future research. The relationship between UV-B and global radiation has been studied and correlation equation for estimating UV-B from global radiation has been deduced. Equation was used for UV-B radiation calculation in eight towns in Vojvodina region during the period 1981-2008. This study also analyzes concentrations of five air pollutant in during the period 2001-2008, and heat index during the period 1992-2008. in seven towns in Vojvodina. The results from this study show growth UV-B radiation and heat index in all towns, and denote particulate maters as main air pollutants in Vojvodina towns.</p>
1022

Air pollution and adverse health effects: Assessing exposure windows and sensitivity to modeling choices

He, Mike Zhongyu January 2020 (has links)
Air pollution is one of the leading environmental problems of the 21st century, and the rise of global urbanization has increasingly exacerbated air pollution’s public health impact. Existing epidemiologic studies have tackled the relationship between air pollution and health from a variety of perspectives, but many areas of research remain lacking, including studies originating from developing countries, the assessment of exposure windows and sensitivity of modeling choices, and a better understanding of the climate change impacts on air pollution and health. In this dissertation, I address all of the issues mentioned above. Chapter 1 formally introduces the topics of this dissertation and summarizes background information on several major air pollutants. It then provides an overview of existing research on air pollution epidemiology and describes key knowledge gaps. In Chapter 2, we conduct a systematic review of the scientific literature for data on fine particulate matter (PM2.5) in China, where historical PM2.5 data are not widely available prior to 2013. Using the 574 PM2.5 measurements we identified from the literature, we detected differences in PM2.5 levels across both geographic and economic regions of China. In Chapter 3, we investigate the associations between short- and intermediate-term exposure of nitrogen dioxide (NO2) and mortality in 42 counties in China from 2013 to 2015, and find evidence of significant associations up to seven days prior to exposure. In Chapter 4, we investigate the association between PM2.5 and hospitalizations in New York State using five separate exposure datasets from 2002 to 2012. We find that despite some fluctuations in effect estimates, the majority of models yielded consistently significantly harmful associations. In Chapter 5, we utilize a global chemistry-climate model to project ozone levels in 2050 under a variety of emissions scenarios and quantify the mortality impact associated with changes in ozone concentrations between 2015 and 2050 according to each scenario. We find that under climate change alone and adherence to current legislation, ozone-related deaths would increase. However, under a best-case scenario of maximum technologically feasible reductions in emissions, over 300,000 premature deaths related to ozone can be avoided. Finally, Chapter 6 summarizes the findings of this dissertation and discusses potential directions in future research. While much work remains to be done, this dissertation work takes an important step forward in closing existing knowledge gaps in the field of air pollution epidemiology. More importantly, we hope that our work sends a strong public health message on the importance of continuing research on air pollution and health.
1023

Modélisation des particules organiques dans l'atmosphère / Modelling organic particles in the atmosphere

Couvidat, Florian 15 November 2012 (has links)
La formation des aérosols organiques dans l'atmosphère est étudiée via le développement d'un nouveau modèle de formation d'aérosols organiques secondaires nommé H²O (Hydrohilic/Hydrophobic Organics). Dans un premier temps, une paramétrisation de la formation d'aérosols via l'oxydation de l'isoprène est développée. Cette paramétrisation prend notamment en compte l'influence des concentrations d'oxydes d'azote sur la formation d'aérosols et leurs propriétés hydrophiles. Ensuite, H²O incluant cette paramétrisation et d'autres développements est évalué par comparaison aux mesures de carbone organique sur l'Europe. Prendre en compte les émissions de composés semi-volatils primaires gazeux (qui peuvent former des aérosols organiques secondaires après oxydation ou se condenser lors de baisses de température) améliore les performances du modèle de manière significative. En revanche, si les émissions de ces composés ne sont pas prises en compte, il en résulte une très forte sous-estimation des concentrations d'aérosols organiques en hiver. La formation d'aérosols organiques secondaires sur l'Île-de-France durant la campagne d'été de Megapoli (juillet 2009) a aussi été simulée pour évaluer les performances du modèle en zone urbaine. H²O donne de bons résultats sur l'Île-de-France bien que le modèle prévoit un pic d'aérosols organiques, provenant des émissions du trafic durant les heures de pointe, qui n'apparaît pas dans les mesures. La présence de ce pic dans les résultats du modèle peut être due à la sous-estimation de la volatilité des composés semi-volatils primaires. Il est aussi possible que les composés organiques primaires et les composés organiques secondaires ne se mélangent pas et que les composés semi-volatils primaires ne peuvent pas se condenser sur un aérosol organique majoritairement secondaire et très oxydé. Enfin, l'impact de la chimie aqueuse est étudié. Le mécanisme utilisé inclue notamment, la formation d'aérosols organiques secondaires dans la phase aqueuse des nuages par oxydation du glyoxal, du méthylglyoxal, de la méthacroleine et de la méthyl-vinyl-cétone, la formation de méthyltétrols dans la phase aqueuse des particules ou des gouttes d'eau des nuages et le vieillissement des aérosols organiques dans un nuage. L'impact des dépôts humides sur la formation d'aérosols est aussi étudié pour mieux caractériser l'impact des nuages sur les concentrations d'aérosols organiques / Rganic aerosol formation in the atmosphere is investigated via the developpement of a new model named H²O (Hydrohilic/Hydrophobic Organics). First, a parameterization is developped to take into account secondary organic aerosol formation from isoprene oxidation. It takes into account the effect of nitrogen oxides on organic aerosol formation and the hydrophilic properties of the aerosols. This parameterization is then implemented in H²O along with some other developments and the results of the model are compaired to organic carbon measurements over Europe. Model performance is greatly improved by taking into account emissions of primary semi-volatile compounds, which can form secondary organic aerosols after oxidation or can condense when temperature decreases. If those emissions are not taken into account, a significant underestimation of organic aerosol concentrations occurs in winter. The formation of organic aerosols over an urban area was also studied by simulating organic aerosols concentration over the Paris area during the summer campaign of Megapoli (July 2009). H²O gives satisfactory results over the Paris area, although a peak of organic aerosol concentrations from traffic, which does not appear in the measurements, appears in the model simulation during rush hours. It could be due to an underestimation of the volatility of organic aerosols. It is also possible that primary and secondary organic compounds do not mix well together and that primary semi volatile compounds do not condense on an organic aerosol that is mostly secondary and highly oxidized. Finally, the impact of aqueous-phase chemistry was studied. The mechanism for the formation of secondary organic aerosol includes in-cloud oxydation of glyoxal, methylglyoxal, methacrolein and methylvinylketone, formation of methyltetrols in the aqueous phase of particles and cloud droplets, and the in-cloud aging of organic aerosols. The impact of wet deposition is also studied to better estimate the impact of clouds on organic aerosol concentrations
1024

Prize-Based Contingency Management: A Vehicle Miles of Travel Reduction Intervention

Marquit, Joshua D. 01 May 2011 (has links)
During the past 50 years, air pollution has become a growing problem throughout the Intermountain West because of increases in personal vehicle ownership and usage. Scientists continue to design interventions to improve air quality by encouraging people to reduce their personal vehicle miles of travel (VMT). However, results of these interventions have only seen modest reductions in VMT because of some methodological and measurement issues. To address these limitations, a 14-week driving reduction intervention was conducted in Cache County, Utah. This intervention employed a prizebased contingency management system within a single-subject, A-B-A withdrawal research design that rewarded participants with prizes if they were able to reduce their VMT below their baseline mean. The VMT was measured each day with an in-car GPS electronic tracking device. Results of this intervention indicate both short- and long-term reductions in VMT as a result of the treatment. Specifically, 6 of the 10 participants showed a statistically significant reduction from the baseline to the intervention stage and maintenance of this reduction during the return-to-baseline stage. The other four participants exhibited a similar pattern but their change in vehicle miles of travel was not statistically significant. Interaction effects were not found between the quo;Choose Clean Airquo; social marketing campaign, gas prices, temperature, and PM 2.5 levels. Despite some problems with the transmission and recording of VMT data, this intervention provides further evidence for the application of prize-based contingency management systems to the reduction of a problematic behavior or encouragement of proenvironmental or pro-social behaviors. The in-car GPS devices improved VMT data collection and quality of the data but hardware and software improvements are still needed to prevent data loss. Further replication is necessary to determine the efficacy of driving reduction intervention that employs prize-based contingency management systems at the community or group level. Future research should also test the possible demographic differences between those that respond favorably to this type of intervention and those that do not, and the differences between prize delivery systems (immediate versus delayed) and prize magnitude (low- versus high-dollar amounts) on driving behaviors.
1025

Three Essays on the Economics of Controlling Mobile-Source Episodic Air Pollution

Acharya, Ramjee 01 August 2018 (has links)
Cache County and the Wasatch Front, Utah have persistently experienced some of the nation’s worst air quality over the past decade. Elevated PM2.5 concentrations during wintertime “red air day” episodes frequently exceed the National Ambient Air Quality Standards (NAAQS). We investigate the possible effects of two different economic policies in controlling these regional problems. Adapting a model originally developed to calculate the social investment necessary to control nationwide disease outbreaks, we estimate an optimal preventative capital stock (for example, investment in public transportation) of between $4.1 million and $14.1 million to control red air day episodes in Cache County, and $133 million to $1.6 billion dollars to control such episodes in the Wasatch Front. Further, we find that a seasonal gasoline tax rate of roughly $8 per gallon is necessary for policy makers in the Wasatch Front to impose at the pump if their goal is to maintain concentrations below the NAAQS on average during a typical winter-inversion season. This rate is roughly $2 more than the rate calculated for Cache County in a previously published study.
1026

Rhinite : caractérisation et association avec la pollution atmosphérique / Rhinitis : characterization and association with air pollution

Burte, Marthe-Emilie 02 March 2018 (has links)
Alors que la rhinite a un fort impact sur la santé publique, chez l’adulte, il n’existe pas de définition standardisée de la rhinite dans les études épidémiologiques. De plus, les facteurs environnementaux de la rhinite sont mal connus et, en particulier, il existe très peu d'études sur les effets à long terme de la pollution atmosphérique sur la rhinite chez l'adulte. Pour combler ces lacunes, nous avons utilisé les données de deux études épidémiologiques multicentriques européennes ayant des données détaillées sur la santé respiratoire et d'exposition annuelle individuelle à la pollution atmosphérique. Nos résultats ont montré que pour mieux caractériser la rhinite, il faut considérer l’ensemble des caractéristiques des symptômes nasaux, les comorbidités et la sensibilisation allergique, et ne pas limiter la maladie à une question ou à un test de sensibilisation allergique. Nous n'avons trouvé aucune association entre la pollution atmosphérique à long terme et l'incidence de la rhinite, mais nous avons montré que l'exposition à long terme à la pollution était associée à une augmentation de la sévérité de la rhinite, soulignant le besoin de contrôler les niveaux de pollution atmosphérique. / Whereas rhinitis has an important public health impact, in adults there is no standardized definition of rhinitis in epidemiological studies. Furthermore, environmental factors of rhinitis are barely known, and in particular, there are very few studies on the effects of long-term exposure to air pollution on rhinitis in adults. To fill these gaps, we used data from two European multicentre epidemiological studies with extensive data on respiratory health and individual estimated exposures to long-term air pollution. Our findings showed that to better characterize rhinitis, one need to consider together all the characteristics of the nasal symptoms, the comorbidities and the allergic sensitization, and not to restrict the disease to one question or one allergic sensitization test. We found no association between long-term air pollution and incidence of rhinitis, but we showed that long-term exposure to air pollution is associated to an increased severity of rhinitis, emphasising that air pollution needs to be controlled.
1027

Analysis of mixing depth variability from EMSU data.

Lui, Patrick Yat-Ki January 1975 (has links)
Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Meteorology. / Bibliography: leaf 94. / M.S.
1028

Investigation of the independent and interactive effects of short-term exposure to particulate matter on human morbidity using epidemiological approaches / 粒子状物質への短期曝露が人の疾患に及ぼす単独影響および相互影響に関する疫学的アプローチを用いた検討

Arthit, Phosri 25 September 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21362号 / 工博第4521号 / 新制||工||1704(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 高野 裕久, 教授 米田 稔, 准教授 上田 佳代 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
1029

Mechanistic Understanding of the Impact of Air Pollution on Human Skin Health

Ji, Liyuan 09 July 2019 (has links)
No description available.
1030

A Unified Exposure Prediction Approach for Multivariate Spatial Data: From Predictions to Health Analysis

Zhu, Zheng 18 June 2019 (has links)
No description available.

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