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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
doi:10.5194/acp-2016-934
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
29 Nov 2016
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Spatial, temporal and source contribution assessments of BC over the northern interior of South Africa
Kgaugelo Euphinia Chiloane1, Johan Paul Beukes1, Pieter Gideon van Zyl1, Petra Maritz1, Ville Vakkari2, Miroslav Josipovic1, Andrew Derick Venter1, Kerneels Jaars1, Petri Tiitta1,3, Markku Kulmala4, Alfred Wiedensohler5, Catherine Liousse6, Gabisile Vuyisile Mkhatshwa7, Avishkar Ramandh8, and Lauri Laakso1,2 1Unit for Environmental Sciences and Management, North-West University, Potchefstroom Campus, South Africa
2Finnish Meteorological Institute, Helsinki, Finland
3Department of Environmental and Biological Sciences, Univ. of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
4Department of Physics, University of Helsinki, Finland
5Leibniz Institute for Tropospheric Research, Leipzig, Germany
6Laboratoire d’Aérologie, Université Paul Sabatier-CNRS, OMP, 14 Avenue Edouard Belin, 31400 Toulouse, France
7Research, Testing and Development, Eskom SOC Ltd, Rosherville, South Africa
8Sasol Technology R&D (Pty) Limited, South Africa
Abstract. After carbon dioxide (CO2), aerosol black carbon (BC) is considered to be the second most important contributor to global warming. Africa is one of the least studied continents, although it is regarded as the largest source region of atmospheric BC. Southern Africa is an important sub-source region, with savannah and grassland fires likely to contribute to elevated BC mass concentration levels. South Africa is the economic and industrial hub of southern Africa. To date, little BC mass concentration data have been presented for South Africa in the peer-reviewed public domain. This paper presents equivalent black carbon (eBC) (derived from an optical absorption method) data collected from three sites, where continuous measurements have been conducted, i.e. Elandsfontein (EL), Welgegund (WG) and Marikana (MA), as well elemental carbon (EC) (determined by evolved carbon method) at five sites where samples were collected once a month on a filter and analysed off-line, i.e. Louis Trichardt (LT), Skukuza (SK), Vaal Triangle (VT), Amersfoort (AM) and Botsalano (BS). All these sites are located in the interior of South Africa.

Analyses of eBC and EC spatial mass concentration patterns across the eight sites indicate that the mass concentrations in the South African interior are in general higher than what has been reported for the developed world and that different sources are likely to influence different sites. The mean eBC or EC mass concentrations for the background sites (WG, LT, SK, BS) and sites influenced by industrial activities and/or nearby settlements (EL, MA, VT and AM) ranged between 0.7 and 1.1, and 1.3 and 1.4 µg/m3, respectively.

Similar seasonal patterns were observed at all three sites where continuous measurement data were collected (EL, MA and WG), with the highest eBC mass concentrations measured during June to October, indicating contributions from household combustion in the cold winter months (June–August), as well as savannah and grassland fires during the dry season (May to mid-October). Diurnal patterns of eBC at EL, MA and WG indicated maximum concentrations in the early mornings and late evenings, and minima during daytime. From the patterns it could be deduced that for MA and WG, household combustion and savannah, and grassland fires were the most significant sources, respectively.

Possible contributing sources were explored in greater detail for EL, with five main sources being identified as coal-fired power stations, pyrometallurgical smelters, traffic, household combustion, as well as savannah and grassland fires. Industries on the Mpumalanga Highveld are often blamed for all forms of pollution, due to the NO2 hotspot over this area that is attributed to NOx emissions from industries and vehicle emissions from the Johannesburg-Pretoria megacity. However, a comparison of source strengths indicated that household combustion, and savannah and grassland fires were the most significant sources of eBC, particularly during winter and spring months, while coal-fired power stations, pyro-metallurgical smelters and traffic contribute to eBC mass concentration levels year round.


Citation: Chiloane, K. E., Beukes, J. P., van Zyl, P. G., Maritz, P., Vakkari, V., Josipovic, M., Venter, A. D., Jaars, K., Tiitta, P., Kulmala, M., Wiedensohler, A., Liousse, C., Mkhatshwa, G. V., Ramandh, A., and Laakso, L.: Spatial, temporal and source contribution assessments of BC over the northern interior of South Africa, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-934, in review, 2016.
Kgaugelo Euphinia Chiloane et al.
Kgaugelo Euphinia Chiloane et al.
Kgaugelo Euphinia Chiloane et al.

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Short summary
This paper presents atmospheric black carbon (BC) data collected in South Africa (SA). In general BC were higher than in the developed world. At one site five sources were identified, with household combustion, and savannah and grassland fires the most significant sources during winter and spring, while coal-fired power stations, pyro-metallurgical smelters and traffic contributed year round.
This paper presents atmospheric black carbon (BC) data collected in South Africa (SA). In...
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