A critical review of health risk assessments of exposure to emissions from coal-fired power stations in South Africa

Emissions from coal-fired power stations increase the incidence of respiratory, cardiovascular and cardiopulmonary diseases and contribute to premature deaths. Wildly varying estimates of the magnitude of these health impacts have been published, however. This paper investigates the reasons for the large discrepancies calculated in five comprehensive health risk assessments of South African coal-fired power station emissions. We review the approaches and input data used by the studies. We also evaluate the exposure-response functions (which relate the pollution concentration to which the population is exposed, to the increase in health risk) used by each study and pay specific attention to whether the exposure-response functions are relevant to the South African context. Health risks are under-estimated in studies that only consider impacts in industrialised areas, or assume high counterfactual concentrations. Health risks are probably over-estimated, however, in other studies which use linear or exponential exposure-response functions that are not applicable in areas where exposure levels are much higher (such as solid fuel-using communities). A more accurate estimate of health effects would be obtained by applying integrated exposure-response functions to quantify health risks at actual exposure levels, and then apportioning the health effects relative to the contribution made by each source to total exposure levels. A fair assessment of the health risk of South Africa’s older coal-fired power stations should also weigh the health costs of the emissions against the health benefits of electricity use in lower income households

Surface Ozone Variability and Trends over the South African Highveld from 1990 to 2007

Surface ozone is a secondary air pollutant formed from reactions between nitrogen oxides (NOx = NO + NO2) and volatile organic compounds in the presence of sunlight. In this work we examine effects of the climate pattern known as the El Nio-Southern Oscillation (ENSO) and NOx variability on surface ozone from 1990 to 2007 over the South African Highveld, a heavily populated region in South Africa with numerous industrial facilities. Over summer and autumn (December-May) on the Highveld, El Nio, as signified by positive sea surface temperature (SST) anomalies over the central Pacific Ocean, is typically associated with drier and warmer than normal conditions favoring ozone formation. Conversely, La Nia, or negative SST anomalies over the central Pacific Ocean, is typically associated with cloudier and above normal rainfall conditions, hindering ozone production. We use a generalized regression model to identify any linear dependence that the Highveld ozone, measured at five air quality monitoring stations, may have on ENSO and NOx. Our results indicate that four out of the five stations exhibit a statistically significant sensitivity to ENSO at some point over the December-May period where El Nio amplifies ozone formation and La Nia reduces ozone formation. Three out of the five stations reveal statistically significant sensitivity to NOx variability, primarily in winter and spring. Accounting for ENSO and NOx effects throughout the study period of 18 years, two stations exhibit statistically significant negative ozone trends in spring, one station displays a statistically significant positive trend in August, and two stations show no statistically significant change in surface ozone

Fuel switching and energy stacking in low-income households in South Africa : a review with recommendations for household air pollution exposure research

DATA AVAILABILITY : This is a review article, and no data were collected. However, all information used to write the manuscript has been included in the supplementary material.Households stack and switch the fuels they use to meet their energy needs for cooking, heating and lighting. The type of fuel used and how fuels are stacked and switched affects household air pollution concentrations and consequently impacts human health. Fuel use patterns are often incorporated into household air pollution studies as an exposure proxy, but this is not always done in a comprehensive manner, especially as the fuel stacking and switching phenomena are excluded from the research methodology. Many low-income households in South Africa do and are likely to continue to stack and switch the fuels they use, including a range of polluting energy sources such as coal or wood, substantially contributing to the country's disease burden. This review paper sought to identify how studies have assessed fuel stacking and switching in the context of household air pollution studies to help guide researchers to develop improved surveys and questionnaires which incorporate household fuel stacking and switching practices in a more detailed manner for exposure studies. While quantitative data remains the gold standard, obtaining detailed information on fuel use practices can significantly improve our understanding of associated air pollution exposure. We demonstrate that more comprehensive and localized studies are necessary when we seek to fully understand fuel stacking and switching practices for household air pollution exposure studies in epidemiological research. This is also important for effective policy development and implementation.The University of Pretoria (South Africa), the South African National Research Foundation, the South African Medical Research Council and the University of Johannesburg, South Africa.https://www.elsevier.com/locate/ersshj2024Geography, Geoinformatics and MeteorologySDG-07:Affordable and clean energ

Contamination of depressional wetlands in the Mpumalanga Lake District of South Africa near a global emission hotspot

The Mpumalanga Lake District (MLD) of South Africa hosts a regionally unique cluster of water bodies of great importance for wetland biodiversity. It is also located close to a global hotspot for coal-fired power station emissions but the local impacts from these sources of pollution are poorly understood. Sediment cores from three contrasting wetlands were 210Pb dated and analysed for a range of contaminants linked to fossil fuel combustion, including trace elements, Hg, sulphur and spheroidal carbonaceous fly-ash particles (SCPs). At the two sites with pre-industrial (1900) baseline sediments, Pb, Zn and especially Cr concentrations and fluxes showed significant increases in the impact period (post-1975). Mercury showed the greatest proportional increase in flux (>4-fold) of all trace metals. Mercury and sulphur concentrations and fluxes showed highly significant correlations with emissions over the corresponding periods, while SCPs in sediments also closely tracked emissions. In a global context, levels of sediment contamination are relatively minor compared with other heavily industrialised regions, with only Cr exceeding the sediment Probable Effects Concentration for biological impact post-1975. Despite the relatively large increases in Hg, concentrations do not reach the Threshold Effects Concentration. The unexpectedly low levels of contamination may be due to i) low levels of many trace contaminants in South African coals compared to global averages, ii) prevailing recirculation patterns which transport pollution away from the study area during the wet season, minimising wet deposition, and iii) pollutant remobilisation through desiccation of wetlands or volatilization. The effects of hydrology and sediment accumulation rates lead to differential transport and preservation of organic-associated and more volatile contaminants (e.g. Hg, S) relative to non-volatile trace elements in wetlands of the MLD. The greatest fluxes of Hg and S are recorded in the site with the highest catchment: lake area ratio, lowest salinity and greatest sediment organic matter content

We cannot continue like this

The book is based on the view that the present trajectory of modern development cannot continue as it is now because it is ecologically unsustainable, it continues to enlarge the gap between rich and poor, and the decolonialisation movement has drawn our attention again to the specific role of religion, culture and value in human affairs and the need for a robust element of indigenisation and contextualisation. This book is strongly focused on the context of Africa, with two chapters that are written by authors from the Netherlands, for the purpose of presenting a North-South dialogue. The book contains reflection on approaches followed in building sustainable human communities in general and reflection on specific efforts to solve sustainability issues. It seeks to integrate academic reflection and insights gained from practical involvement with sustainability issues in local communities and low-income households, with contributions from Theology and Natural and Social Sciences

An Environmental Justice Perspective on Air Quality Offsets

Air quality offsets in South Africa are intended to counterbalance the harm caused by atmospheric emissions and deliver a net ambient air quality benefit in the affected airshed. In practice, they are implemented as a condition of leniency from compliance with the Minimum Emission Standards, and they focus on converting solid fuel burning households in low-income communities to cleaner forms of energy. Air quality offsets are not supported by all stakeholders, with non-governmental organisations in particular voicing vociferous objections. To date, there have only been very limited analyses of the ethical dimensions of air quality offsets. In this paper, air quality offsets and the Minimum Emission Standards are examined and compared from the perspective of three notions of environmental justice: distributive justice, which focuses on the distribution of environmental burdens and benefits; procedural justice, which considers inclusion and exclusion in decision- and policy-making processes; and justice as recognition, which focuses on the cultural and institutional processes that determine recognition, misrecognition and non-recognition of various groups. It is found that air quality offsets should guide action which promotes distributive justice because they are focussed on reducing polluting emissions in vulnerable, low-income communities that are exposed to the highest levels of ambient pollution. From a procedural justice perspective, South Africa’s legislative processes provide for involving most stakeholders in decision-making processes. Air quality offset initiatives should be evaluated once they have been implemented at scale to determine whether they have indeed aided in redressing injustices. Assessment criteria could include whether the air quality-related health risk of vulnerable communities has been reduced, whether community members have participated in the design and implementation of interventions, and whether marginalised members of the community have benefitted from the interventions

The impacts of commissioning coal-fired power stations on air quality in South Africa: insights from ambient monitoring stations

The South African electricity sector is known for its heavy reliance on coal. The aim of this study is to assess the impacts of increasing SO2 and PM emissions from the three return-to-service power stations (Komati, Camden and Grootvlei), and the newly constructed Medupi power station on ambient air quality measured in the vicinities of these power stations. Trends in ambient pollution concentrations were determined using Theil-Sen analysis. The correlation between the emissions and ambient pollution concentrations at nearby monitoring stations was determined with the Spearman partial rank correlation coefficient.  Lastly, compliance of ambient pollution concentrations with the South Africa National Ambient Air Quality Standards was assessed. Few statistically significant trends in ambient SO2 and PM10 concentrations are found, and there is little correlation between increasing power station emissions and ambient pollutant concentrations in the vicinity. It is only at Camden monitoring station where there are increases in PM10 concentrations from the direction of Camden power station, and at Grootvlei monitoring station where increasing SO2 concentrations are from the directions of Grootvlei and Lethabo power stations. A strong, positive correlation between power station emissions and ambient concentrations exists only for SO2 at Grootvlei monitoring station and PM10 at Medupi monitoring station (although it is likely that the correlation at Medupi is related to construction and vehicle activity, and not emissions from Medupi power station stacks). It is concluded that the establishment of monitoring stations in the vicinities of power stations is necessary but not sufficient to monitor their impact on air quality in the surrounds