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- Volume 25, Issue 2, 2015
Clean Air Journal = Tydskrif vir Skoon Lug - Volume 25, Issue 2, 2015
Volume 25, Issue 2, 2015
Reflections on the Workshop on International and National Landscape of Atmospheric Mercury and the NACA Conference, 1-2 October 2015 : guest editorialAuthor Ian HedgecockSource: Clean Air Journal = Tydskrif vir Skoon Lug 25 (2015)More Less
It was a great privilege to be invited to talk at the 'Workshop on International and National Landscape of Atmospheric Mercury', and to give a presentation at this year's National Association for Clean Air Conference with the conference theme of "Shifting Challenges of Air Quality in South Africa".
ARSAIO overview : Atmospheric Research in Southern Africa and Indian Ocean : a South Africa-France bilateral collaborative programme : newsSource: Clean Air Journal = Tydskrif vir Skoon Lug 25, pp 3 –4 (2015)More Less
The "Atmospheric Research in Southern Africa and Indian Ocean" (ARSAIO) project is a research consortium of more than 25 researchers and 30 students. It is funded through a bi-lateral research programme between South Africa and France. The first phase was completed in December 2013. Now in its second phase, the project shall be completed by the end of 2017. Here, we provide an overview of the Universities/Institutes involved and French and South African co-ordinators who are investigating the structure and dynamics of the atmosphere by utilising different in-situ, space-borne and model simulation techniques.
Mercury measurements at Cape Point, South Africa - an update on recent findings : highlighted local researchSource: Clean Air Journal = Tydskrif vir Skoon Lug 25 (2015)More Less
Mercury (Hg) is regarded as a highly toxic, heavy metal and is also considered as a global pollutant due to its long range transport and bio-accumulation in the aquatic nutrition chain, which is not fully understood yet. For this reason and also to initiate international legislation aimed at controlling the use of mercury, a European Union-funded Global Mercury Observing System (GMOS), in which the Cape Point Global Atmospheric Watch (GAW) station participated, was initiated in 2010. The South African Weather Service (SAWS) as well as the Council for Scientific and Industrial Research (CSIR) have been conducting mercury measurements at the Cape Point GAW station since 1995 and 2007, respectively. While SAWS focussed on the measurement of Gaseous Elemental Mercury (GEM) in air, the CSIR has carried out analyses of Total mercury (TotHg) in precipitation samples. The GEM measuring programme, which is ongoing, has led to several publications dealing with long-term trends, seasonal cycles, depletion events and continental emission estimates for Hg.
Source: Clean Air Journal = Tydskrif vir Skoon Lug 25 (2015)More Less
Mercury is a globally important toxin that has the potential to cause significant adverse impacts to human and environmental health. Mercury that is released from natural or anthropogenic activities has the ability to enter the atmosphere and due to its long atmospheric lifespan it is able to be transported great distances around the world. As part of the biogeochemical cycling of mercury, gaseous elemental mercury (GEM) (the most abundant species of atmospheric mercury, accounting for >90% of the total atmospheric mercury) is able to be oxidised and is deposited in water and on land, where it undergoes further biogeochemical cycling to form methylated mercury.
Mercury emissions in South Africa - perspective from the Department of Environmental Affairs : commentaryAuthor Vincent GololoSource: Clean Air Journal = Tydskrif vir Skoon Lug 25 (2015)More Less
The Department of Environmental Affairs (DEA) recognises the need to protect human health and the environment from anthropogenic emissions of mercury. In 2003, various governments agreed on the need for global action on mercury based on its adverse health and environmental effects. Later, in 2009, they negotiated a legally-binding instrument on mercury and established the Intergovernmental Negotiating Committee (INC). Five INC negotiation sessions were held and in January 2013, the negotiations were finalised. The content of the convention, known as the Minamata convention, was adopted in October 2013 in Minamata, Japan and South Africa was a signatory of the convention.
Author Patricia ForbesSource: Clean Air Journal = Tydskrif vir Skoon Lug 25 (2015)More Less
On the 30 September 2015, a workshop entitled "International and National Landscape of Atmospheric Mercury" was held in Bloemfontein prior to the start of the annual National Association for Clean Air (NACA) Conference. Dr Ian Hedgecock of the CNRInstitute of Atmospheric Pollution Research in Italy provided a global context to atmospheric mercury levels, impacts and policy and highlighted challenges faced (see his commentary for more information), whilst Dr Vincent Gololo of the Department of Environmental Affairs provided a summary of the status of the development of the South African mercury emissions inventory.
Source: Clean Air Journal = Tydskrif vir Skoon Lug 25, pp 9 –11 (2015)More Less
Mercury (Hg) is a naturally occurring element that is present in air, water and soil. It exists in three main forms namely elemental mercury, inorganic mercury compounds and organic mercury compounds (WHO, 2007). The atmosphere is the leading transport pathway of mercury emissions, while land and ocean processes maintain a central role in mercury redistribution among terrestrial, marine and freshwater ecosystems (Driscoll et al., 2013). The biogeochemical cycling of mercury is complex, comprising various transport and transformation progressions that define the fate of mercury and the health risks on ecosystem and humans (Liu et al., 2011).
Source: Clean Air Journal = Tydskrif vir Skoon Lug 25, pp 12 –16 (2015) http://dx.doi.org/10.17159/2410-972X/2015/v25n2a1More Less
The household combustion of solid fuels, for the purpose of heating and cooking, is an activity practiced by many people in South Africa. Air pollution caused by the combustion of solid fuels in households has a significant influence on public health. People most affected are those considered to be the poorest, living in low-income settlements, where burning solid fuel is the primary source of energy. Insufficient data has been collected in South Africa to quantify the concentrations of particulate emissions that people are exposed to, especially the respirable fraction, associated with the combustion of solid fuels. The aim of this paper is to gain an understanding of the particulate matter (PM) concentrations a person living in a typical household in a low income settlement in the South African Highveld is exposed to. It also seeks to demonstrate that the use of solid fuels in the household can lead to indoor air pollution concentrations reaching levels very similar to ambient PM concentrations, which could be well in excess of the National Ambient Air Quality Standards, representing a major national public health threat. A mobile monitoring station was used in KwaDela, Mpumalanga to measure both ambient particulate concentrations and meteorological conditions, while a range of dust/particulate monitors were used for indoor and personal particulate concentration measurements. Indoor and personal measurements are limited to the respirable fraction (PM4) as this fraction contributes significantly to the negative health impacts. The sampling for this case study took place from 7-19 August 2014. Highest particulate matter concentrations were evident during the early mornings and the early evenings, when solid fuel burning activities were at their highest. Indoor and personal daily average PM4 concentrations did not exceed the 24h National Ambient PM2.5 Standard of 65 µg/m3 nor did they exceed the 24h National Ambient PM10 Standard of 75 µg/m3. The outdoor PM2.5 concentrations were found to be below the standards for the duration of the sampling period. The outdoor PM10 concentrations exceeded the standards for one day during the sampling period. Results indicate that, although people in KwaDela may be exposed to ambient PM concentrations that can be non-compliant to ambient standards, the exposure to indoor air, where solid fuel is burnt, may be detrimental to their health.
Source: Clean Air Journal = Tydskrif vir Skoon Lug 25, pp 17 –25 (2015) http://dx.doi.org/10.17159/2410-972X/2015/v25n2a2More Less
Climate change could potentially affect a number of variables that impact the dispersal of and human exposure to air pollutants, as well as climate dependent sectors such as wind energy. This study attempted to quantify the projected changes in seasonal daily mean wind speeds for South Africa around the mid-21st century (2051-2075) under two different atmospheric heat pathways. Seasonal daily mean wind speed increases rarely reach 6% and decreases occur to a maximum of 3% and are variable between different seasons and areas within the country. In all seasons except December-January-February, wind speeds are projected to increase in the Highveld region, suggesting that air pollution dispersing conditions could increase. Wind direction at the 850hPa-level show minor changes, except over the Western and Eastern Cape provinces.
Source: Clean Air Journal = Tydskrif vir Skoon Lug 25, pp 26 –35 (2015) http://dx.doi.org/10.17159/2410-972X/2015/v25n2a3More Less
During the casting of ferromanganese alloys from electric arc furnaces into sand beds at temperatures of up to 1800°C a considerable amount of very brown fumes are generated when the alloy fume is oxidized in the atmosphere. The fume is difficult to capture because of the large flux of gas that is generated. Possible reasons for this flux include the high evaporation rate of Mn at elevated temperatures, the large surface area of the casting beds and the large thermal plumes over the furnace tapholes and casting beds. It has been found that the use of fine water sprays along the edge of the roof that covers the casting bed resulted in a significant reduction in visible emissions. This paper describes research into the kinetics of the fume to improve the design of the capture hoods, as well as the mechanism of suppression by the water sprays by using CFD analysis. It is shown that the oxidation reaction produces less than 20% of the energy content of the plume over the arc furnace taphole, and also that radiation heat transfer may play an important role in increasing the energy content of the taphole plume. The capture of fume particles by fine spray droplets is shown to have limited efficiency, while the heat sink that is caused by evaporation does not materially contribute to the circulation of fume through the spray. It is postulated that the increased moisture content of the air over the casting beds may be instrumental in reducing the oxygen partial pressure or in the formation of an oxide layer, both of which would reduce metal evaporation and, therefore fume formation. The exact mechanism requires further investigation.
Quality Assurance of Continuous Emission Monitoring Systems : a practitioner's guide/technical reportAuthor Gerald WoollattSource: Clean Air Journal = Tydskrif vir Skoon Lug 25, pp 36 –41 (2015) http://dx.doi.org/10.17159/2410-972X/2015/v25n2a4More Less
In 2004, the National Environmental Management Act (NEMA) and regulations were promulgated and by 2010 were gazetted into law for the first time in South Africa. Under the NEMA, the Air Quality Act 39 of 2004 (AQA) was promulgated and included priority pollutants identified by the Department of Environmental Affairs (DEA) as having or may have a significant detrimental effect on the environment, including health, social conditions, economic conditions, ecological conditions or cultural heritage. In this context continuous emission monitoring of emissions to air is a requirement under many of the operators as Air Emission Licenses (AEL) issued under section 21 of AQA. The quality of data obtained from continuous emission monitors is ensured by the inclusion of the BS EN14181:2004 (revised standard updated to current BS EN14181:2014) European standard which has been adopted into the South African legislation for this purpose. With this in mind the purpose of this technical paper is to provide an overview of the current status of automated measuring systems (AMS)/continuous emission monitors (CEMs) currently in use by industry to monitor emissions in South Africa, in terms of compliance with relevant emission limit values (ELVs) and the current challenges faced with ensuring the quality and reliability of the data obtained.