| 1. |
- Howlett-Downing, Chantelle, et al.
(författare)
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PM2.5 Chemical Composition and Geographical Origin of Air Masses in Pretoria, South Africa
- 2022
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Ingår i: Water, Air, and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 233
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Tidskriftsartikel (refereegranskat)abstract
- In Africa, there is a paucity of studies that reported on PM2.5, soot, BC, UV-PM (organic carbon) and trace element levels in rural and urban regions. PM2.5 samples were collected over 24 h and every third day during 19 April 2018 and 28 February 2020. The mean PM2.5 level was 24.1 μg.m−3 (range: 2.9–139 μg.m−3). PM2.5 levels exceeded the yearly World Health Organization (WHO) air quality guideline (5 μg.m−3). The daily WHO guideline (15 μg.m−3) was exceeded on 151 of the 228 days. The mean soot, black carbon and organic carbon levels were 1.43 m−1 × 10−5, 2.7 μg.m−3 and 2.1 μg.m−3, respectively. Twelve PM2.5-bound trace elements (Br, Ca, Cl, Cu, Fe, K, Ni, S, Si, Ti, U and Zn) were analysed. The geographical origin of air masses that passed the study site was estimated using the Hybrid Single-Particle Lagrangian Integrated Trajectory software. Four air masses were identified. The observed PM2.5, soot, BC, UV-PM and trace element levels at this urban background study site could potentially pose a significant risk to human health.
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| 2. |
- Howlett-Downing, Chantelle, et al.
(författare)
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Source Apportionment of PM2.5 and PM2.5-Bound Trace Elements in Pretoria, South Africa
- 2023
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Ingår i: ENVIRONMENTAL FORENSICS. - 1527-5922 .- 1527-5930.
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Tidskriftsartikel (refereegranskat)abstract
- Outdoor PM2.5 samples were collected for 34 months in Pretoria, South Africa from 18 April 2017 to 28 February 2020. The average total PM2.5 concentration was 23.2 +/- 17.3 mu g.m(3) (0.69-139 mu g.m(-3)), with the highest mean recorded during winter and the lowest during summer (p < 0.05). The sources were determined by means of cross referencing the US EPA PMF 5.0 program and the NOAA HYsplit model. The sources of the total PM2.5 were mining (33%), resuspended dust (24%), industry (15%), general exhaust (12%), vehicular emissions (12%) and biomass burning (4%). Sources of air pollutants are both ubiquitous and seasonal.Highlights center dot In central Pretoria, the largest contributing sources of PM2.5 are resuspended dust matrix and mining from surrounding areas;center dot A winter analysis was run where As, Se and Pb was included in the dataset, confirming biomass burning sources which were typically higher during the winter season; and center dot Air quality management policies should address both ubiquitous and seasonal sources.
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| 3. |
- van der Westhuizen, Deidré, et al.
(författare)
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Atmospheric fine particulate matter (PM2.5) in Bloemfontein, South Africa
- 2022
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Ingår i: International Journal of Environmental Analytical Chemistry. - : Informa UK Limited. - 0306-7319 .- 1029-0397.
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Tidskriftsartikel (refereegranskat)abstract
- Indoor and outdoor pollution has become a worldwide problem; it impacts both the environment and human health. Research-driven air pollution assessment studies were done in some of the larger South African cities like Cape Town and Pretoria, but almost none in the Free State province. The purpose of the present study was to determine PM2.5 levels and its chemical components over a period of more than one year in the Free State capital, Bloemfontein. Particulate matter was collected on PFTE filters, which were then analysed gravimetrically, by smoke stain reflectometry and X-ray fluorescence. The average PM2.5 concentration for the study period was 11μg/m3, which exceeded the World Health Organization (WHO) annual guideline limit (5μg/m3), but not the annual South African National Ambient Air Quality Standard (20μg/m3). The daily WHO guideline (15μg/m3) was exceeded on 28days, but not the daily South African standard (40μg/m3). The average soot concentration was 1.2μg/m3. The five most abundant trace elements detected in the PM2.5 filter samples were K, Ca, Si, S and Fe.
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| 4. |
- van der Westhuizen, Deidre, et al.
(författare)
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Source apportionment of fine atmospheric particles in Bloemfontein, South Africa, using positive matrix factorization
- 2024
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Ingår i: ENVIRONMENTAL MONITORING AND ASSESSMENT. - 0167-6369 .- 1573-2959. ; 196:2
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Tidskriftsartikel (refereegranskat)abstract
- Air pollution is of major health and environmental concern globally and in South Africa. Studies on the sources of PM2.5 air pollution in low- and middle-income countries such as South Africa are limited. This study aimed to identify local and distant sources of PM2.5 pollution in Bloemfontein. PM2.5 samples were collected from June 16, 2020 to August 18, 2021. Trace element concentrations were determined by EDXRF spectroscopy. By use of the US EPA PMF 5.0 program, local sources were determined to be combustion/wood burning (49%), industry (22%), soil dust (10%), base metal/pyrometallurgical and traffic (9.6%) and water treatment/industry (9.4%). The HYSPLIT program was applied to determine distant PM2.5 source areas and the following clusters were identified: Mpumalanga province (52%), Northern Cape province (35%), Indian Ocean (8%) and Atlantic Ocean (6%). The majority of the air was found to come from the Mpumalanga province in the north-east, while the majority of local sources are ascribed to combustion/wood burning. Results from this study can be used to develop an Air Quality Management Plan for Bloemfontein.
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