No description available.

No description available.

No description available.

Lephalale Municipality is a predominantly rural Municipality with 38 villages, two townships (Marapong and Onverwacht) and one town, Lephalale. Lephalale, formerly known as Ellisras, is a town situated in the “heart of the Bushveld” in Limpopo province. The town is growing rapidly and more industries are becoming concentrated within this small town. The construction of Medupi power station which is underway and other projects such as the expansion of Grootegeluk mine (coal 3 and 4 projects), and road developments in the area; have led to concern about the ambient air quality of the area. Other possible future projects are the Coal to Liquid project by Sasol and the Coal Bed Methane project by Anglo American Thermal Coal. The purpose of this study is to determine the ambient air quality impact of the Matimba power station in the Lephalale area. The AERMOD model and ambient air quality data obtained from Eskom’s Grootstryd and Marapong monitoring stations were used to assess the ambient air quality of Lephalale. Sulphur dioxide and Nitrogen oxides were investigated. Both the model’s results and the ambient air quality monitoring data indicated that the power station contributes to high -ground level concentrations of Sulphur dioxide. AERMOD simulated the nitrogen oxides results as nitrogen dioxide. From the study it is concluded that the power station is not the only source of nitrogen oxides. Nitrogen oxides concentrations were associated with low-level sources. The relationship between the criteria pollutants in this study was assessed. The study found that there is no relationship between sulphur dioxide and nitrogen oxides. This finding was used to support the idea that sulphur dioxide and nitrogen oxides are from different sources. It was also established that seasonality has an influence on the ground level concentrations of pollutants in the area.

Dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg for the Degree of Master of Science. / Recent research has highlighted the lack of information on elevated absolutely stable layers per se throughout the troposphere over the southern African subcontinent. Hence a climatology of elevated absolutely stable layers is derived for each of four predominant synoptic circulation types over Southern Africa; namely semi-permanent continental anticyclones, transient mid-latitude ridging anticyclones, westerly wave baroclinic disturbances and barotropic quasi-stationary easterly waves. The horizontal and vertical structures as well as the temporal persistence of elevated absolutely stable layers are analysed using radiosonde data from nine South African aerological stations from the period 1986-1993. In addition, a climatology is derived for the mid-winter stability maximum, during the month of July from 1989-1993, in order to gain greater insights into the influence of anticyclonic circulation on the elevated absolutely stable layers. Four non-surface stable layers are identified over the country, at approximately the 800 hPa, 700 hPa, 500 hPa and 300 hPa levels. The lower of these layer occurs only over the coastal regions. All of the discontinuities exhibit a high degree of persistence and appear to be rapidly reconstructed subsequent to synoptic scale disturbances. The presence of these layers has obvious implications for local as well as global pollution transport, since stable discontinuities trap pollutants below their bases and act as upper air boundaries. As a consequence, global-scale transport of aerosols and trace gases in the free air is controlled to a large degree by these discontinuities. Greater insights into the mechanisms controlling such large-scale transport are essential in ascertaining southern Africa's contribution to greenhouse gas concentrations. Moreover, the persistence and strength of the discontinuities have implications for rainfall over the subcontinent, with the lower layers in particular acting as a vertical boundary to turbulence and mixing, and thus hindering the development of convective precipitation. / AC 2018

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2015. / The air quality over the Bojanala District has been identified as an area of concern. The Bojanala Platinum District falls within the Waterberg Priority Area, which was declared as a priority area for air quality in 2012. This study was conducted in the southern part of the Bojanala district to identify the spatial and temporal distribution of aerosols over the district. Aerosol optical thickness and Ångstrom exponent were derived using data retrieved from direct solar radiation measurements using hazemeters during winter 2008, early winter 2009 and late winter 2010. Results of the study reveal that aerosol loadings differ significantly as winter progresses. AOT levels are found to be considerably higher during winter and late winter, compared with the early winter campaign. Diurnal variation during the late winter campaign is found to be very similar to that of the early winter campaign, with little variation in aerosol loadings and characteristics during the day; while the winter 2008 campaign reveals a significant decreasing trend in AOT and Ångstrom exponent as the day progresses. The AOT and Ångstrom exponent levels for the different campaigns, local sources and the diurnal trends identified assist in the attribution of domestic fuel burning practices; and the concentration of pollutants emitted in the area by inversion layers to the characteristics of the aerosol loadings during winter. The high AOT and contribution of fine mode particles during late winter is attributed to the onset of the biomass burning season. The importance of industrial sources to the aerosol loadings is clear during all three campaigns; however, it is clear that aerosols at different levels in the atmosphere have a significant impact on AOT over the district. The vertical distribution of aerosols is explored through the use of trajectories and associated surface wind roses which indicate that foreign airmasses from the Mpumalanga Highveld and the Atlantic Ocean clearly have a significant impact on the aerosol loadings over the Bojanala District and are associated with extremes in AOT levels. Further, spatial analysis reveals that the highest concentrations of aerosols (associated with larger particles) are identified toward the eastern side of the district except during late winter. It is probable that the aerosols in the Bojanala District may have a significant regional climatic impact which requires further investigation.

No description available.

This thesis examines the relationship between childhood exposure to air pollution and long-term health. The research is based on an earlier study (1978-1986) that examined the relationship between exposure to air quality and respiratory health for a cohort of elementary school-aged children (n=3,202). These children resided in four distinct neighbourhoods in Hamilton, Ontario, which exhibited significant gradients in air pollution levels. Informed by the Life Course Health Development model, a survey was developed and administered on a reconstructed cohort (n = 395). The following objectives were addressed: 1) to determine the current health status of the reconstructed cohort; 2) to assess the potential relationship between childhood exposure to air pollution and adult respiratory health; and, 3) to explore factors mediating this relationship. Data was collected for a range of variables including residential and occupational histories, socio-demographic variables, and health outcomes. The dataset was merged with data from childhood on respiratory health, exposure to air pollution, and socio-demographic variables. Results indicate that a relatively high percentage of respondents had asthma in childhood (11%) compared to the original cohort (5.5%). In addition, prevalence rates of most health outcomes were higher than those of the Canadian population. Despite the gradient in air pollution levels, there were no significant differences in health status across neighborhoods. However, results of bi-variate and multi-variate analysis indicate possible significant associations between childhood exposure to S02 and hospital visits for asthma, asthma incidence in adulthood, and ever being diagnosed with asthma for females. For males, results suggest that childhood exposure to S02 is not linked to respiratory health. Factors related to the macro and micro environments also play significant roles in long-term health. This thesis made significant contributions to knowledge by suggesting that childhood exposure to S02 may impact long-term respiratory health for females, and may be linked to inflammatory diseases. / Thesis / Doctor of Philosophy (PhD)

Climate change is already harming public health through warmer, more erratic weather and many downstream consequences. Research can support climate change adaptation by characterizing climate-related exposures, identifying vulnerable populations, and identifying effective interventions. Furthermore, the main source of greenhouse gas emissions, fossil fuel combustion, also produces air pollutants such as fine particulate matter (PM2.5) that directly harm human health. In this dissertation my colleagues and I have examined the effects of short-term temperature exposure on myocardial infarction and stroke to inform adaption (Chapters 1 to 3) and leveraged multiple exposure models to estimate annual PM2.5 concentrations and quantify uncertainty (Chapter 4). To examine the effects of short-term temperature exposure, we conducted case-crossover analyses using an administrative dataset of hospitalizations in New York State. For PM2.5 prediction and uncertainty characterization, we applied a flexible ensemble approach to leverage seven already-developed PM2.5 models. Overall, we found that warmer hourly temperatures and greater daily temperature variability increased the risk of ischemic events, and lower hourly temperatures increased the risk of hemorrhagic stroke. The ensemble model showed high predictive accuracy, demonstrating the strength of this approach, and we observed greatest uncertainty in the Pacific Northwest and southeast coast. The methods applied in this dissertation can be applied to other exposures and in different settings to further quantify the risks of climate impacts and improve air pollution assessment. Future research should examine the joint impacts of multiple weather factors, strategies to protect people in group housing from extreme weather, measurements and models to reduce uncertainty of air pollution exposures, and propagate exposure uncertainty into health models. However, the need for further research should not delay climate action today.

Childhood asthma is one of the most common chronic diseases worldwide, including in South Africa. There has been substantial evidence on the role of air pollution in asthma exacerbation but limited research on the role of climate change and how the interaction between climate change and air pollution is affecting childhood asthma, specifically in low and middle-income countries (LMICs). Temperature changes can be used as an effect of climate change to investigate the association between climate change, air pollution and childhood asthma. This study, therefore, used a case study approach aimed at examining the interaction between air pollution and temperature in exacerbating childhood asthma focusing on clinical data obtained from Red Cross War Memorial Children's Hospital, air quality data (City of Cape Town) and temperature data (South African Weather Services) for Cape Town, South Africa for three study years (2009, 2014 and 2019). The protocol (Part A) of the mini dissertation describes childhood asthma literature globally and in LMICs and specifically in South Africa. It also discusses the increasing incidences and prevalence of the disease and possible causes such as air pollution and climate change. Furthermore, it discusses the vulnerability of children to the exposure of interest, being air pollution (PM2.5, PM10, NO2 and O3) and climate change (i.e., temperature). Subsequently, the development of air quality standards is discussed, specifically concerning whether they consider the specific children's vulnerability to exposures. The protocol then describes the study population and methodologies for conducting this study. The journal ready article (Part B) presents the findings of the study. Spearman's correlation was used to measure the degree of association between temperature variables and air pollutants. The results indicated that diurnal temperature was associated with PM2.5 (r=0.579: p< 0.01) and PM10 (r=0.505: p< 0.01). A Poisson regression analysis was applied to evaluate the relationship between asthma exacerbation with air pollutants and temperature variables. In a univariate analysis there was a statistically significant relationship between asthma exacerbation and diurnal temperature for 2019, IRR=0.98 (95% CI,0.97 – 0.99) p< 0.05, maximum temperature 2014, IRR=0.99(95% CI, 0.98 - 1.00) p< 0.05 and for 2019, IRR=0.98(95% CI, 0.97 - 0.99) p< 0.01, average temperature 2014, IRR=0.99(95% CI, 0.98 - 1.00) p< 0.05 and for 2019, IRR=0.98(95% CI, 0.97 - 0.99) p< 0.01. Using a multivariate analysis there v of 110 was no significant relationship between childhood asthma exacerbation and air pollutants (PM10, NO2 and O3) except for PM2.5 IRR=0.12(95% CI, 0.01 - 0.81) p< 0.05. Diurnal temperature statistically significant childhood asthma predictor for 2009, IRR=1.02(95% CI, 1.00 - 1.05) p< 0.05 and for 2014, IRR=0.97(95% CI, 0.96 - 0.99) p< 0.01. Temperature increase, therefore, seems to be related to asthma exacerbation. More research is needed on the relationship between diurnal temperature, childhood asthma, and air pollutants to inform adaptation strategies. The findings of this study are important for the development of climate change and health adaptation and prevention strategies in South Africa, particularly in relation to heat adaptation. These findings are also relevant for the development of air quality guidelines and guidelines to address children, as the most vulnerable population to environmental health exposures. The appendices (Part C) present the analyses that were not included in the protocol (Part A) and article (Part B). These also include documents relating to the study such as ethics approval and permission to conduct research by different entities.