• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 677
  • 400
  • 118
  • 45
  • 39
  • 23
  • 18
  • 12
  • 12
  • 12
  • 12
  • 12
  • 12
  • 11
  • 8
  • Tagged with
  • 1800
  • 1800
  • 462
  • 388
  • 337
  • 242
  • 217
  • 189
  • 176
  • 164
  • 163
  • 153
  • 150
  • 145
  • 144
  • 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.
851

Evaluation on Health Impact of Government Support for GER (Traditional Dwelling) District's Electricity Night Rates in Ulaanbaatar City

Nansalmaa, Erdenekhuu 07 May 2011 (has links)
During the last 10 years, air pollution has become one of the major public health problems in Ulaanbaatar city of Mongolia, and concentrations of pollutants were measured 3 to 50 times higher than WHO recommendation. This devastating air pollution is produced mostly by thousands of families who migrated from countryside and live in gers (traditional dwellings) in the suburban area which is not connected to the central heating system, and nearly all of them burn coal to keep them warm. Due to air pollution, residents living in Ulaanbaatar city suffer health problems that equal to the smoking of 4-5 packs of cigarettes. During the winter time, PM10 hourly average concentrations increased to 2,300 μg/m3, and daily average became over than 1,000 μg/m3 in the most polluted parts of the city. At present, Mongolian government has accepted that the health of Mongolian residents has deteriorated at an alarming level. In January of 2011, Mongolian Parliament approved the Law on Reduction of Air Pollution in the Capital City to control air pollution and eliminate the gaps in practice. One main provision of this law was to improve ger district electricity transmission and distribution network and reduce the night-time price of electricity by 50 percent. Therefore, this study aimed to estimate direct health benefits of Government Provision on cutting electricity payment by 50 percent during the night time and analyze the efficiency of this program on reducing air pollution and its related health impact. The study result showed when this new regulation is fully implemented in the ger districts, the annual consumption of coal and wood would be decreased by about 550,000 tons and 415,000 tons, accompanied by massive reduction of the emission. These changes would lead into noteworthy health benefits such as 15.7 and 17.4 percent of reduction of total and infant mortality rates and 4.3 and 4.7 percent decrease of cardiovascular and respiratory disease morbidity cases, annually.
852

Effects of Estimated Exposure to Cumulative Traffic-Related Pollutants on Asthma, Cardiovascular, and Stroke Outcomes in an Urban Area

Boothe, Vickie L. 25 November 2008 (has links)
BACKGROUND: A growing body of research has suggested that exposure to traffic-related emissions is associated with numerous adverse health effects including prevalence and severity of symptoms of asthma, hospitalizations for acute myocardial infarctions, and cardiovascular-related mortality. No previous studies have assessed the association between proximity to traffic and respiratory and cardiovascular outcomes across all age groups. OBJECTIVE: The purpose of this study was to assess the association between proximity to traffic emissions within the City of Atlanta and respiratory and cardiovascular 911 Emergency Management Service (EMS) calls and subsequent emergency department (ED) visits. METHODS: Case and control diagnostic groups were established for 5,450 EMS calls received between 2004 and 2008 from residents of the City of Atlanta based on ICD-9 codes assigned within the ED. Case diagnostic groups included asthma, cardiovascular outcomes, and stroke. Gastrointestinal diagnostic groups were selected as controls. Cumulative traffic within a 100 m buffer of the call origination location was used as an indicator of exposure to traffic emissions. Using a case-control study design, the associations between exposure to traffic emissions and the case diagnostic groups were evaluated using logistic regression, controlling for potential confounding factors including age, gender, ethnicity, and socio-economic status (SES). Subgroup analyses were performed to evaluate differences by select age categories, gender, and SES. P-values of <0.05 and 95% confidence intervals (CI) were used to determine statistical significance. RESULTS: Increased cumulative traffic near the call location was associated with an increase in the odds of an EMS call and ED visit for cardiovascular outcomes compared to the control diagnostic group even after adjustment for confounding factors (OR = 1.07; 95% CI ,1.01-1.12). The strongest effects were among men and individuals aged 40-75 years. Increased cumulative traffic was also associated with an increased odds of an EMS call and ED visit for stroke among individuals aged 18-39 years after adjusting for confounding (OR = 1.16; 95% CI, 1.01-1.34). No statistically significant associations were found between increased cumulative traffic and the odds of an EMS call and ED visit for asthma. CONCLUSION: These results provide additional evidence that proximity to traffic is associated with adverse cardiovascular outcomes and stroke in certain age groups.
853

Ozone Damage Potential to Loblolly Pine Ecosystems in Metropolitan Atlanta, Georgia

Styers, Diane Marie 20 May 2005 (has links)
Atlanta is one of the largest metropolitan areas in the southeastern United States and is the only area in the region currently listed in “serious” 1-hour ozone nonattainment. Despite its exceedance history, impacts on Atlanta’s urban forests have not been the focus of any major studies. The purpose of this study was to examine air pollution damage to vegetation using a foliar-injury survey on Stone Mountain. The objectives of this project included 1) establishing that pollution transport from Atlanta to Stone Mountain occurs, 2) determining the magnitude of ozone concentrations near Stone Mountain and 3) assessing sensitive plant species on Stone Mountain for foliar injury. Results from this study confirm that Stone Mountain is located downwind from Atlanta. Ozone concentrations were sufficiently high to damage vegetation and these consistently peaked in July. Foliar injury was present on understory species on Stone Mountain, but was not observed on loblolly pine species.
854

Kauno miesto miškų absorbcinės gebos įvertinimas / Assessment of Kaunas urban forests effects to air pollution mitigation

Aleknavičiūtė, Aušra 28 June 2008 (has links)
Kauno miesto miškų medžių absorbcinės gebos įvertinimas buvo atliktas i-tree programos UFORE techniniu modeliu. Taip pat šia programa įvertinta Kleboniškio, Panemunės, Romainių, Ąžuolyno miesto parko absorbcinė geba. Airviro programos pagalba nustatytos oro teršalų koncentracijos mieste, pavaizduota grafiškai emisijų sklaida. Nustatyta procentinė dalis oro taršos sumažėjimo, kurią lemia Kauno miesto miško želdiniai. Duomenis apie želdinius Kauno mieste ir pasirinktuose analizuoti parkuose naudoti remiantis Kauno miesto savivaldybės teritorijoje esančių miškų taksoraščiu (VĮ Valstybinis miškotvarkos institutas, miškų inventorizacija 2003/2004) bei atliktais matavimais Kleboniškio, Panemunės, Romainių ir ��žuolyno parkuose. Meteorologinius duomenis oro taršai nustatyti pateikė VŠĮ „Kauno aplinkos kokybės tyrimai“. Rezultatai parodė, kad Kauno miesto miško medžiai per metus pašalina 328 tonas pagrindinių atmosferos teršalų: 97,7 t ozono, kietųjų dalelių pašalinta 87,3 t, azoto dioksido 81 t, sieros dioksido 42,4 t, anglies monoksido 19,3 t. Pagal procentinę sudėtį ozono tarp pagrindinių pašalintų atmosferos oro teršalų yra 29,9 %, kietųjų dalelių 26,6 %, azoto dioksido 24,7 %, sieros dioksido 12,8%, anglies monoksido 6%. Didžiausias teršalų kiekis pašalinamas Kleboniškio miško parke - 38,7 tonos (39 % bendro analizuojamų parkų pašalintų teršalų kiekio), toliau seka panemunės miško parkas - 35,7 tonos (36%), Romainių miško parkas - 20,4 tonos ( 20 %) ir Ąžuolynas - 5 tonos (5%)... [toliau žr. visą tekstą] / Assessment of Kaunas Urban forest effects and air pollution mitigation was done using i-tree program UFORE model. During the study four different city parks were analyzed – Kleboniskis, Panemune, Romainiai, Azuolynas. Kaunas city air pollution concentrations were counted with Airviro program. Data required for this study was used from Kaunas city trees inventory book 2004, as well field data has been collected from city parks in random sample of fixed area plots in April of 2008. VŠĮ “Kauno aplinkos kokybės tyrimai “delivered meteorogical data about Kaunas city. Results showed, that Kaunas city forest remove about 328 metric tones of atmospheric air pollutants per year. In addition these trees remove 97,7 metric tones of O3, 87,3 metric tones of particulate matter, NO2 – 81 metric tones, SO2 – 42,4 metric tones, CO – 19,3 metric tones. The biggest part of pollutants have been removed in the park of Kleboniskis – 38,7 metric tones (39% of total air pollutants removed in the analyzed city parks), Panemune park removed 35,7 metric tones (36%), Romainiai park - 20,4 metric tones (20%), ąžuolynas- 5 metric tones ( 5 %). Results presented, that Kaunas city urban forest are able to sequestrate 3365 metric tones of Carbon per year, all Kaunas urban forest trees could storage 237210 metric tones of carbon. The city parks carbon storage are: Panemune park trees - 25 metric tones, Kleboniskis park trees -13 metric tones, Romainiai park trees -12,5 metric tones, Ąžuolynas park... [to full text]
855

Kerpių bioindikacinių savybių panaudojimas oro taršai Kuršėnų mieste įvertinti / Application of bioindicational features of lichens for the assessment of air pollution in kuršėnai city

Gasiūnas, Vytautas 20 August 2013 (has links)
Bakalauro darbo tikslas - pagal kerpių rūšių gausumą ir kerpėmis dengiamą plotą ant medžių kamienų tam tikrame objekte nustatyti oro užterštumą. Darbo objektas – kerpės, augančios Kuršėnų mieste ant medžių katilinės poveikio zonoje. Darbas atlikas 2012 metų liepos - rugpjūčio mėnesiais. Kuršėnų mieste vyraujantys vėjai yra pietvakarių. Nuo katilinės vyraujančių vėjų kryptimi (PV) pažymėtame transekte 1 km intervalais išdėstyti 5 tyrimo bareliai (30x30 m pločio). Tokia pat tvarka nuo darbo objekto išdėstyti 5 tyrimo bareliai priešinga kryptimi (prieš vyraujančių vėjų kryptį (ŠR)). Kiekviename barelyje nuo kiekvienos medžių rūšies buvo paimti kerpių mėginiai, nustatytas jų kamieno procentinis padengimas. Darbe nustatytos visos kerpių rūšys, augančios ant medžių kamienų. Tirtoje teritorijoje identifikuota 15 kerpių rūšių: 7 lapiškosios ir 8 žiauberiškosios. Daugiausiai kerpių rūšių aptikta trijuose bareliuose kurie yra nutolę 4 ir 5 kilometrais nuo taršos objekto prieš vyraujančių vėjų kryptį (ŠR) ir 5 kilometrais pagal vyraujančių vėjų kryptį (PV) šiuose bareliuose buvo rasta po 6 kerpių rūšis. / The aim of this final paper of the Bachelor degree is measuring air pollution according to the abundance of species of lichens as well as the area covered by lichens on the trunks of the trees. The object of this work is lichens who grow on trees in Kuršėnai city. Pollution source is boiler-house of “Siauliai Energy”. Experiment was carried out in July - August months 2012. Kuršėnai is dominated by southwestern (SW) winds. In the selected transect stretching from the boiler-house in the direction of prevailing winds, southwest (SW), the study plots (30x30 m) were located at 1 km intervals from each other. According to the same ordering, study plots in the opposite direction were set out (against the prevailing wind direction (NE)). This paper identifies all kinds of lichen that grow on tree trunks in the area. Fifteen species of lichens were identified in the investigated area. More specifically, 7 foliose and 8 crustose were found. Most species of lichen grow in the outskirts of the city, while the least amount of them was found close to the source of pollution.
856

Estimating the Effects of Air Pollutants on Recurrent Hospital Admission for Respiratory Diseases

2013 October 1900 (has links)
Recurrent data are widely encountered in many applications. This thesis work focuses on how the recurrent hospital admissions relate to the air pollutants. In particular, we consider the data for two major cities in Saskatchewan. The study period ranges from January 1, 2005 to December 30, 2011 and involves 20,284 patients aged 40 years and older. The hospital admission data is from the Canadian Institute for Health Information (CIHI). The air pollutants data is from the National Air Pollution Surveillance Program (NAPS) from Environment Canada. The data set has been approved by the Biomedical Research Ethics Board, University of Saskatchewan. The gaseous pollutants included in this study are carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), as well as particulate matter PM2:5 (tiny particles in the air that are 2:5 microns in width). In the data analysis, we applied three different existing models to all respiratory diseases and asthma, respectively. The three models are the Poisson process model (also called Andersen-Gill model), the Poisson process model with the number of previous events as a covariate and the Poisson process model with shared gamma distributed frailties (random effects). For all respiratory diseases, the Poisson process model with random effects provides the best t in comparison to the other two models. The model output suggests that the increased risk of hospital readmission is significantly associated with increased CO and O3. For asthma, the Poisson process model provides the best t in comparison to the other two models. We found that only CO and O3 have significant effects on recurrent hospital admissions due to asthma. We concluded this thesis with the discussion on the current and potential future work.
857

Urban ecosystems and human health in South Africa : examining the relationships between housing, energy, indoor air quality and respiratory health

Savage, Leah Krystyn 03 October 2007 (has links)
In South Africa one of the strongest influences on domestic indoor air quality is the type of energy used for heating, cooking and other household purposes. Emissions from fuel combustion, along with housing factors, can result in respiratory infections, a leading cause of death in the country. In this study I examine the relationships between energy types, patterns of use, housing conditions such as improper ventilation and overcrowding, indoor air quality and respiratory health in poorer communities of Msunduzi Municipality, South Africa. These variables were examined using an ecohealth perspective through the integration of data concerning individual time-activity budgets, housing materials and structure, energy sources used for heating, cooking and lighting, respiratory symptoms and continuous real time monitoring of indoor air pollutants (particulate matter (PM), carbon dioxide (CO2), carbon monoxide (CO) and sulphur dioxide (SO2)). A total of 20 dwellings, displaying large variability in housing structure and energy patterns, were sampled for 24 hours (hr) over a period of 60 days. The mean 24-hr average indoor concentrations measured were as follows: PM2.5= 16 ± 11 µg/m3, PM10= 78 ± 46 µg/m3, CO= 5 ± 6 ppm and SO2= 0.18 ± 0.27 ppm. Mean indoor concentrations measured were significantly greater than mean outdoor concentrations (p<0.0001 (PM2.5), p=0.017 (PM10), p<0.0001 (CO), p<0.0001 (SO2)). Although PM concentrations increased with the use of increasingly inefficient-burning fuel types (gas < paraffin < wood), no significant differences in the means were found across these fuel types. It is thought that the high degree of variability among dwellings and the small sample size in this study obscured any statistically significant relationships. No significant differences in mean concentrations were found across different housing types either. Indoor exposures were, on average, highest among very young children (ages 0-5) and elders (ages 51+). All age groups reported experiencing high levels of respiratory symptoms, with the elder group (ages 51+) reporting the highest percentages for each symptom. This study will be used to inform local governments and NGOs of local indoor air pollution and exposure risks, so that policy and resources can be allocated accordingly to improve physical environments. / Thesis (Master, Environmental Studies) -- Queen's University, 2007-09-27 08:52:05.443
858

Etude des pluies acides à Schefferville, N.Q. et de la possibilité de leur association à un transport atmosphérique de polluants sur de longues distances

Daoust, Mario. January 1982 (has links)
No description available.
859

The whole is greater than the sum of its parts : cumulative risk of indoor air pollution and urban vulnerability in Cato Manor.

Binedell, Michelle Louise. January 2003 (has links)
Low-income communities are potentially more vulnerable to physical, social and environmental hazards than wealthier communities. The lack of services associated with these communities (such as water supply, sanitation facilities and electrification) has increased the exposure of households to health hazards. These households also lack the coping mechanisms and resources to deal with the stress that these hazards impose on them. This study is concerned with the potential health hazards imposed from indoor air pollution. Traditional health risk assessments are used to determine the level of risk to human health from a variety of chemical or biological hazards. What these assessments do not include however, is a measure of the vulnerability of the household. The aim of this study therefore, was to develop a methodology for generating a vulnerability index for the inclusion of factors underlying urban poverty and vulnerability into a risk assessment of indoor air pollution. The approach adopted in this study followed an iterative and inductive pathway. Theories on risk assessment and urban vulnerability were explored in order to understand the manner in which risk to human health is assessed and compounded by vulnerability. Secondary data sources as well as a household survey provided information that aided the selection of a number of vulnerability indicators. These indicators were chosen as measures of vulnerability specifically for low-income households in South African settlements. The findings of the research show that there are a number of factors or issues which underlie vulnerability. The issues are related to demographics, livelihoods, physical exposures, externalities, services and general health. This study used a four-tiered selection approach to sift through the issues of vulnerability and to transform the key issues into a set of vulnerability indicators which make up the vulnerability index. / Thesis (M.Sc.)-University of Natal, Durban, 2003.
860

Air quality management in the uMhlathuze municipality using air dispersion modelling.

Haripursad, Yegambal. January 2007 (has links)
Air pollution has increased over time due to human population growth, industrialisation and other economic activities which have led to global and localised deterioration in air quality. The uMhlathuze Municipality, located on the KwaZulu-Natal North Coast is one such local area that has a rapidly developing Industrial Development Zone, currently comprising many large and small scale industries. These large-scale operations are amongst South Africa’s largest process industries and operate continuous combustion processes which release significant quantities of air pollutants into the atmosphere. These pollutants include reduced sulphur gases, mercaptans, hydrogen sulphide, sulphur dioxide (SO2), sulphur trioxide, carbon dioxide, particulate fluoride and ammonia. In light of the promulgation of the National Environmental Management: Air Quality Act (AQA) of 2004 and the need to assess ambient air quality, the contribution of air dispersion modelling to ambient air quality management in the uMhlathuze Municipality was assessed using SO2 as an indicator pollutant. The Gaussian puff urban air dispersion model called Calpuff was used to model five scenarios including a control run with actual emissions data; a worst-case run using permitted emissions data; and three emissions reduction scenarios using 25%, 50% and 75% reductions of the permitted data.. The results of these modelling scenarios were compared with results of other modelling studies recently conducted in the uMhlathuze Municipality, as well as with the South African Ambient Air Quality Standards (SAAAQS) for SO2. The results revealed that the permitted emissions scenario led to exceedances of the SAAAQS 1-hour and 24-hour average concentrations over most of the uMhlathuze Municipal area. The use of the permitted emissions values produced higher SO2 concentrations over the study area than the control run that comprised current emissions values. The control scenario produced similar results to the scenario in which there was a 50% reduction in permitted emissions data and suggests that the industries are operating at half of their permitted levels of SO2 emissions. The reduction of the permitted emission by 75% shows a significant decrease in the area exceeding the SAAAQS 1-hour standard, and compliance with the SAAAQS 24-hour and annual average standards. The results of this study for the control scenario based on actual emissions were higher than previous studies conducted in uMhlathuze due to a larger quantity of SO2 emissions used in the modelling exercises, different meteorological data sets and different air dispersion models used. However, there is a close correspondence between the Airshed (2006) results and this study when similar quantities of SO2 emissions were modelled in the permitted emissions scenario. In view of the exceedances experienced in the control run and permitted emissions scenarios, it is likely that under the AQA, some reduction in emissions will be required. In line with the Department of Environmental Affairs and Tourism National Framework classification system, the City of uMhlathuze is likely to fall under a Class 4 area, in which ambient concentrations of SO2 can pose a threat to the health and well-being of people. Immediate air quality management action plans that have specific timeframes for compliance with the ambient standards are required. The National Framework notes that the air quality impact of an industry will be assessed before an Atmospheric Emission License is granted and implies that each industry is required to undertake an air quality specialist study to determine its individual impact on ambient air quality. The air quality specialist study should include air dispersion modelling to assess the ambient SO2 concentrations; a health risk assessment based on the results of the dispersion modelling; and mitigation measures that are required to ensure compliance with ambient standards through the use of the Best Practicable Environmental Option (BPEO). / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2007.

Page generated in 0.0861 seconds