scholarly journals Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igeneous Complex, South Africa

2012 ◽  
Vol 12 (1) ◽  
pp. 1895-1934 ◽  
Author(s):  
A. Hirsikko ◽  
V. Vakkari ◽  
P. Tiitta ◽  
H. E. Manninen ◽  
S. Gagné ◽  
...  
Keyword(s):  
South Africa ◽  
Particle Number ◽  
Geographical Area ◽  
Mineral Resources ◽  
Particle Formation ◽  
Geological Structure ◽  
Platinum Group Metals ◽  
Ambient Conditions ◽  
Industrial Emissions ◽  
Micron Particle

Abstract. South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring in a large geological structure termed the Bushveld Igeneous Complex (BIC). The majority of the world's platinum group metals (PGMs) and chromium originate from the BIC. Considering the importance of PGMs in the manufacturing of automotive catalytic converters, as well as the relatively poor current state of air quality and the general lack of atmospheric research in the BIC, atmospheric related research in this geographical area is of local (South African) and of international interest. The western limb of the BIC is the most exploited, with at least eleven pyrometallurgical smelters occurring within a 55 km radius. Due to the lure of employment in the industrialised BIC, the area is populated by informal, semi-formal and formal residential developments. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distribution and concentration measurements were conducted for over two years at Marikana in the heart of the western BIC. Our results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO2-based nucleation (from industrial emissions) was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. Secondary particle formation was influenced both by local pollution sources and regional ambient conditions. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during nucleation events were similar to the results from a semi-clean savannah site in South Africa.

scholarly journals Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa

2012 ◽  
Vol 12 (9) ◽  
pp. 3951-3967 ◽  
Author(s):  
A. Hirsikko ◽  
V. Vakkari ◽  
P. Tiitta ◽  
H. E. Manninen ◽  
S. Gagné ◽  
...  
Keyword(s):  
South Africa ◽  
Air Quality ◽  
Particle Number ◽  
Mineral Resources ◽  
Particle Formation ◽  
Geological Structure ◽  
Back Trajectory ◽  
Igneous Complex ◽  
Micron Particle ◽  
Bushveld Igneous Complex

Abstract. South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring and being processed in a large geological structure termed the Bushveld Igneous Complex (BIC). The area is also highly populated by informal, semi-formal and formal residential developments. However, knowledge of air quality and research related to the atmosphere is still very limited in the area. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distributions and number concentrations, together with meteorological parameters, trace gases and particulate matter (PM) were measured for over two years at Marikana in the heart of the western BIC. The observations showed that trace gas (i.e. SO2, NOx, CO) and black carbon concentrations were relatively high, but in general within the limits of local air quality standards. The area was characterised by very high condensation sink due to background aerosol particles, PM10 and O3 concentration. The results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO2-based nucleation followed by the growth by condensation of vapours from industrial, residential and natural sources was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. The air mass back trajectory and wind direction analyses showed that the secondary particle formation was influenced both by local and regional pollution and vapour sources. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during nucleation events were similar to results previously published for a semi-clean savannah site in South Africa.

scholarly journals Observation of new particle formation in subtropical urban environment

2011 ◽  
Vol 11 (8) ◽  
pp. 3823-3833 ◽  
Author(s):  
H. C. Cheung ◽  
L. Morawska ◽  
Z. D. Ristovski
Keyword(s):  
Growth Rate ◽  
Urban Environment ◽  
Size Distribution ◽  
Particle Number ◽  
Particle Growth ◽  
Particle Formation ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
Industrial Emissions ◽  
Traffic Exhaust

Abstract. The aim of this study was to characterise the new particle formation events in a subtropical urban environment in the Southern Hemisphere. The study measured the number concentration of particles and its size distribution in Brisbane, Australia during 2009. The variation of particle number concentration and nucleation burst events were characterised as well as the particle growth rate which was first reported in urban environment of Australia. The annual average NUFP, NAitken and NNuc were 9.3×103, 3.7×103 and 5.6×103 cm−3, respectively. Weak seasonal variation in number concentration was observed. Local traffic exhaust emissions were a major contributor of the pollution (NUFP) observed in morning which was dominated by the Aitken mode particles, while particles formed by secondary formation processes contributed to the particle number concentration during afternoon. Overall, 65 nucleation burst events were identified during the study period. Nucleation burst events were classified into two groups, with and without particles growth after the burst of nucleation mode particles observed. The average particle growth rate of the nucleation events was 4.6 nm h−1 (ranged from 1.79–7.78 nm h−1). Case studies of the nucleation burst events were characterised including (i) the nucleation burst with particle growth which is associated with the particle precursor emitted from local traffic exhaust emission, (ii) the nucleation burst without particle growth which is due to the transport of industrial emissions from the coast to Brisbane city or other possible sources with unfavourable conditions which suppressed particle growth and (iii) interplay between the above two cases which demonstrated the impact of the vehicle and industrial emissions on the variation of particle number concentration and its size distribution during the same day.

scholarly journals Observation of new particle formation in subtropical urban environment

2010 ◽  
Vol 10 (10) ◽  
pp. 22623-22652 ◽  
Author(s):  
H. C. Cheung ◽  
L. Morawska ◽  
Z. D. Ristovski
Keyword(s):  
Growth Rate ◽  
Urban Environment ◽  
Size Distribution ◽  
Particle Number ◽  
Particle Growth ◽  
Particle Formation ◽  
Number Concentration ◽  
Vehicle Emission ◽  
Particle Number Concentration ◽  
Industrial Emissions

Abstract. The aim of this study was to characterise the new particle formation events in subtropical urban environment Southern Hemisphere. The study measured the number concentration of particles and its size distribution in Brisbane, Australia during 2009. The variation of particle number concentration and nucleation burst events were studied and the particle growth rate was characterised which was first reported in urban environment of Australia. The annual average NUFP, NAitken and Nnuc were 9.3×103, 3.7×103 and 5.6×103 cm−3, respectively. Weak seasonal variation in number concentration was observed. Local vehicle emission was major contributor of the pollution observed in the morning which was dominated by the Aitken mode particles, while particle formed by secondary formation process was contributed to the particle number concentration in the afternoon. 65 nucleation burst events were identified during the study period. Nucleation burst events were classified into two groups with and without particle growth after the burst of nucleation mode particles observed. Average particle growth rate of the nucleation events was 4.6 nm hr−1 (ranged from 1.79–7.78 nm hr−1). Case studies of the nucleation burst events were characterised including i) the nucleation burst with particle growth which was associated with the particle precursor emitted from local vehicle emission, ii) the nucleation burst without particle growth which was due to the transport of industrial emissions from the coast to Brisbane city, and iii) interplay between the above two cases which demonstrated the impact of the vehicle and industrial emissions on the variation of particle number concentration and its size distribution during the same day.

Ores Sources, Smelters and Archaeometallurgy: Exploring Iron Age Metal Production in the Southern Waterberg, South Africa

2013 ◽  
Vol 11 (2) ◽  
pp. 243-267 ◽  
Author(s):  
Foreman Bandama ◽  
Shadreck Chirikure ◽  
Simon Hall
Keyword(s):  
South Africa ◽  
Iron Age ◽  
Southern Africa ◽  
Mineral Resources ◽  
Limpopo Province ◽  
Metal Working ◽  
Cultural Interaction ◽  
Metal Production ◽  
European Colonization ◽  
Sem Analyses

The Southern Waterberg in Limpopo Province is archaeologically rich, especially when it comes to evidence of pre-colonial mining and metal working. Geologically, the area hosts important mineral resources such as copper, tin and iron which were smelted by agriculturalists in the precolonial period. In this region however, tin seems to be the major attraction given that Rooiberg is still the only source of cassiterite in southern Africa to have provided evidence of mining before European colonization. This paper reports the results of archaeological and archaeometallurgical work which was carried out in order to reconstruct the technology of metalworking as well as the cultural interaction in the study area and beyond. The ceramic evidence shows that from the Eiland Phase (1000–1300 AD) onwards there was cross borrowing of characteristic decorative traits amongst extant groups that later on culminated in the creation of a new ceramic group known as Rooiberg. In terms of mining and metal working, XRF and SEM analyses, when coupled with optical microscopy, indicate the use of indigenous bloomery techniques that are widespread in pre-colonial southern Africa. Tin and bronze production was also represented and their production remains also pin down this metallurgy to particular sites and excludes the possibility of importing of finished tin and bronze objects into this area.

Annual and interannual variation in boreal forest aerosol particle number and volume concentration and their connection to particle formation

Tellus B ◽  
2008 ◽  
Vol 60 (4) ◽  
Author(s):  
Miikka Dal Maso ◽  
Antti Hyvärinen ◽  
Mika Komppula ◽  
Peter Tunved ◽  
Veli-Matti Kerminen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Aerosol Particle ◽  
Interannual Variation ◽  
Particle Number ◽  
Volume Concentration ◽  
Particle Formation

Impact of Urban Pollution on Organic-Mediated New-Particle Formation and Particle Number Concentration in the Amazon Rainforest

2021 ◽  
Vol 55 (8) ◽  
pp. 4357-4367
Author(s):  
Bin Zhao ◽  
Jerome D. Fast ◽  
Neil M. Donahue ◽  
Manish Shrivastava ◽  
Meredith Schervish ◽  
...  
Keyword(s):  
Particle Number ◽  
Urban Pollution ◽  
Particle Formation ◽  
Number Concentration ◽  
Amazon Rainforest ◽  
Particle Number Concentration ◽  
New Particle Formation

scholarly journals Quantitative and Qualitative Research on the Waste from the Mining of Rock Raw Materials in Lower Silesia

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 375 ◽  
Author(s):  
Urszula Kaźmierczak ◽  
Jan Blachowski ◽  
Justyna Górniak-Zimroz ◽  
Herbert Wirth
Keyword(s):  
Raw Materials ◽  
Mineral Resources ◽  
Geological Structure ◽  
Mining Activity ◽  
Road Engineering ◽  
Quantitative And Qualitative Research ◽  
Sw Poland ◽  
Natural Aggregates ◽  
Graphical Presentation ◽  
Lower Silesia

The Lower Silesia area in SW Poland is characterized by a geological structure that is conducive to mining activity. The exploitation of rock raw materials plays an important role in this sector of the economy. By the end of 2017, there were in total approximately 400 current concessions for the exploitation of rock raw materials in the analysed area (Polish Geological Institute, MIDAS database—Management and Protection System of Polish Mineral Resources). The conducted mining activity results in waste, which in the greatest amount occurs in the process of obtaining crushed road and construction aggregates, natural aggregates, carbonate raw materials for the cement and lime industry, as well as stone elements for construction and road engineering. At the end of 2016, the mining plants accumulated 26,569,600 Mg of waste. As part of the European Regions Toward Circular Economy (CircE) project, research was conducted on the volume and composition of the mining waste of rock raw materials in the years 2010–2016 within Lower Silesia. This research used the methods of statistical, descriptive and spatial analysis to identify mining plants with the highest potential for using their wastes. In the course of this study, 6 mining plants with the highest potential of using their waste for industrial production purposes were selected. In order to objectively select these plants, the methodology of qualitative multi-criteria analysis was developed, and 7 criteria were selected for assessing the economic potential of using waste from the mining of rock raw materials. An additional result of this research is a database and graphical presentation of changes in the spatial distribution of generated waste in the Lower Silesia region in the years ranging from 2010 to 2016.

scholarly journals Conserving a geographically isolated Charaxes butterfly in response to habitat fragmentation and invasive alien plants

Koedoe ◽  
2015 ◽  
Vol 57 (1) ◽  
Author(s):  
Casparus J. Crous ◽  
James S. Pryke ◽  
Michael J. Samways
Keyword(s):  
South Africa ◽  
Tree Species ◽  
Geographical Area ◽  
Alien Plants ◽  
Western Cape ◽  
Forest Patches ◽  
Agricultural Matrix ◽  
Conservation Implications ◽  
Invasive Tree Species ◽  
Remnant Forest

In South Africa, much of the forest biome is vulnerable to human-induced disturbance. The forest-dwelling butterfly Charaxes xiphares occidentalis is naturally confined to a small forest region in the south-western Cape, South Africa. Most of the remaining habitat of this species is within a fragmented agricultural matrix. Furthermore, this geographical area is also heavily invaded by alien plants, especially Acacia mearnsii. We investigated how C. x. occidentalis behaviourally responds to different habitat conditions in the landscape. We were particularly interested in touring, patrolling and settling behaviour as a conservation proxy for preference of a certain habitat configuration in this agricultural matrix. Remnant forest patches in the agricultural matrix showed fewer behavioural incidents than in a reference protected area. Moreover, dense stands of A. mearnsii negatively influenced the incidence and settling pattern of this butterfly across the landscape, with fewer tree settlings associated with more heavily invaded forest patches. This settling pattern was predominantly seen in female butterflies. We also identified specific trees that were settled upon for longer periods by C. x. occidentalis. Distance to a neighbouring patch and patch size influenced behavioural incidences, suggesting that further patch degradation and isolation could be detrimental to this butterfly. Conservation implications: We highlight the importance of clearing invasive tree species from vulnerable forest ecosystems and identify key tree species to consider in habitat conservation and rehabilitation programmes for this butterfly. We also suggest retaining as much intact natural forest as possible. This information should be integrated in local biodiversity management plans.

scholarly journals Modeling particle nucleation and growth over northern California during the 2010 CARES campaign

2015 ◽  
Vol 15 (21) ◽  
pp. 12283-12313 ◽  
Author(s):  
A. Lupascu ◽  
R. Easter ◽  
R. Zaveri ◽  
M. Shrivastava ◽  
M. Pekour ◽  
...  
Keyword(s):  
Size Distribution ◽  
Particle Number ◽  
Particle Formation ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Particle Nucleation ◽  
Particle Number Concentration ◽  
New Particle Formation ◽  
Organic Vapors ◽  
Diurnal Variability

Abstract. Accurate representation of the aerosol lifecycle requires adequate modeling of the particle number concentration and size distribution in addition to their mass, which is often the focus of aerosol modeling studies. This paper compares particle number concentrations and size distributions as predicted by three empirical nucleation parameterizations in the Weather Research and Forecast coupled with chemistry (WRF-Chem) regional model using 20 discrete size bins ranging from 1 nm to 10 μm. Two of the parameterizations are based on H2SO4, while one is based on both H2SO4 and organic vapors. Budget diagnostic terms for transport, dry deposition, emissions, condensational growth, nucleation, and coagulation of aerosol particles have been added to the model and are used to analyze the differences in how the new particle formation parameterizations influence the evolving aerosol size distribution. The simulations are evaluated using measurements collected at surface sites and from a research aircraft during the Carbonaceous Aerosol and Radiative Effects Study (CARES) conducted in the vicinity of Sacramento, California. While all three parameterizations captured the temporal variation of the size distribution during observed nucleation events as well as the spatial variability in aerosol number, all overestimated by up to a factor of 2.5 the total particle number concentration for particle diameters greater than 10 nm. Using the budget diagnostic terms, we demonstrate that the combined H2SO4 and low-volatility organic vapor parameterization leads to a different diurnal variability of new particle formation and growth to larger sizes compared to the parameterizations based on only H2SO4. At the CARES urban ground site, peak nucleation rates are predicted to occur around 12:00 Pacific (local) standard time (PST) for the H2SO4 parameterizations, whereas the highest rates were predicted at 08:00 and 16:00 PST when low-volatility organic gases are included in the parameterization. This can be explained by higher anthropogenic emissions of organic vapors at these times as well as lower boundary-layer heights that reduce vertical mixing. The higher nucleation rates in the H2SO4-organic parameterization at these times were largely offset by losses due to coagulation. Despite the different budget terms for ultrafine particles, the 10–40 nm diameter particle number concentrations from all three parameterizations increased from 10:00 to 14:00 PST and then decreased later in the afternoon, consistent with changes in the observed size and number distribution. We found that newly formed particles could explain up to 20–30 % of predicted cloud condensation nuclei at 0.5 % supersaturation, depending on location and the specific nucleation parameterization. A sensitivity simulation using 12 discrete size bins ranging from 1 nm to 10 μm diameter gave a reasonable estimate of particle number and size distribution compared to the 20 size bin simulation, while reducing the associated computational cost by ~ 36 %.

scholarly journals Governance and socio-political issues in management of acid mine drainage in South Africa

Water Policy ◽  
2017 ◽  
Vol 20 (1) ◽  
pp. 77-89
Author(s):  
Charles Mpofu ◽  
Thabiso John Morodi ◽  
Johan Petrus Hattingh
Keyword(s):  
South Africa ◽  
Decision Making ◽  
Acid Mine Drainage ◽  
Environmental Governance ◽  
Mine Drainage ◽  
Mineral Resources ◽  
Political Issues ◽  
Acid Mine ◽  
Black Economic Empowerment ◽  
Decision Making Processes

Abstract The water resources in South Africa are threatened by current and past mining practices such as abandoned and closed mines. While mining is considered valuable for its contribution to this country's gross domestic product, its polluting effects on water and land resources have been criticised as unsustainable. Acid mine drainage (AMD) is one specific public health and ecological issue that has stirred debates in political and social circles in this country. This paper examines the scalar politics and other related dimensions of water and AMD governance, thereby revealing evidence of deep-rooted challenges regarding the governance of water and mineral resources. The specific focus is on the socio-political context of labour laws and Black Economic Empowerment and the decision-making processes adopted by government. Thus, this paper has implications for the improvement of environmental governance and decision-making strategies and the adoption of a national strategy for adequately addressing AMD and related policy issues.

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