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Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa
Thesis (MSc)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613854130765824 |
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| access_status_str | Open Access |
| author | Gaoaaga, Kereemang |
| author2 | Fietz, Susanne |
| author_browse | Fietz, Susanne Gaoaaga, Kereemang |
| author_facet | Fietz, Susanne Gaoaaga, Kereemang |
| author_sort | Gaoaaga, Kereemang |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132379 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:42:44.343Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132379 Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa Gaoaaga, Kereemang Fietz, Susanne Vos, Heleen C. Stellenbosch University. Faculty of Science. Dept. of Earth Sciences. Particles -- Environmental aspects Particulate matter -- Environmental aspects Air -- Pollution -- South Africa -- Measurement Environmental geochemistry Air quality -- South Africa -- Western Cape Environmental management -- South Africa -- Western Cape Urban ecology (Biology) -- South Africa -- Western Cape UCTD Thesis (MSc)--Stellenbosch University, 2025. Gaoaaga, K. 2025. Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/4575c987-e588-4b5e-b64c-47eaa82ac69f ENGLISH ABSTRACT: Air Quality is globally recognised as major health concern, including in South Africa where in addition to outdoor air quality, clean indoor air quality is a challenge, especially in low-income and informal settlements. The fine inhalable fraction of particulate matter, specifically PM2.5, are key concern in household air quality assessment. Indoor fine inhalable particles with aerodynamic diameter of 2.5 µm or less also known as PM2.5 concentrations vary spatiotemporally and such variability affects the pollution exposure levels. Therefore, It is essential to analyse the chemical composition of indoor PM2.5 to identify and trace their potential sources. In addition to source appointment, a clear understanding of the chemical composition also ultimately assists the assessment how these particle emissions may challenge human health. Therefore, this study aimed to monitor indoor fine inhalable particles (i.e., PM2.5) concentrations, examine the elemental composition and characterise the morphology of captured PM2.5. This allowed to identify potential sources and evaluate health risk assessment in informal settlements of the Western Cape, South Africa. The study was conducted from December 2022 to March 2024 in households at eight residential settlements in Western Cape. Low-cost sensors and particle size-fractionating Ultrasonic Personal Air Samplers were simultaneously used for monitoring indoor PM2.5 and capturing indoor PM2.5. Both (sensors and samplers) were exposed over a 24hrs sampling period at each household. Nineteen trace metals were analysed through ICP- MS, and morphological characterization carried out through the SEM-EDS (particle type, shape and size). The Chemical Daily Intakes (CDI) through ingestion, skin exposure, and inhalation were estimated to assess if exposure to trace metals indoors challenges human health. To solve the origin of indoor PM2.5, positive matrix factorization (PMF) was utilized. HYSPLIT backward trajectory analysis and wind rose diagrams assisted in understanding the particle transport pathways and wind distributions at study sites. The PM2.5 and trace metals concentrations peaked in winter and were lowest in summer. The daily median PM2.5 concentrations varied greatly from each other, the highest concentration was 44 µg/m3 at Forest Village and lowest was 6 µg/m3 at Nyanga. The indoor PM2.5 exceeded by 50% the daily averages recommended in the WHO guidelines (15 µg/m3) and the SA IAQ guidelines (25 µg/m3). In total, the mass of the captured indoor PM2.5 during this study, at multiple households over the 24 hours sampling period was up to 0.84 g. We observed a seasonal pattern in dust composition, with less concentrations of Al, Fe, Zn, Ba in summer. Winter had higher concentrations of more complex dust composition. Major metals were Al, Mn, Fe, Zn, Sr, Ba. Potentially toxic elements included Pb, Cd, As, in both seasons, with seasonal addition of Cr (summer) and Se and Cu (winter). These potentially toxic elements occasionally exceeded the safe limit for non-carcinogenic risk (based on calculations of the globally accepted Hazard Index), however, the cancer risk values in PM2.5 were below the maximum tolerable margin. This implies that trace metals bound to indoor PM2.5 has significant health effect on residents, that may cause other diseases and illnesses but not cancer risk. Based on the health risk assessment, children are most affected by indoor PM2.5 associated trace metals. The morphological study indicated that there are three categories of particles captured, i.e., geogenic, anthropogenic and biogenic particles. The particles are characterized by irregular shapes, rounded/spherical, spores and pollen grains. The potential sources identified in this study are rather ambient dust than indoor-sourced emissions related, such as traffic-related emissions, industrial emissions, agricultural practices, resuspended road dust, mineral dust. HYSPLIT backward trajectory analysis during the study timeframe revealed that air mass that reached and covered around the settlements predominantly from the SSW and SE oceanic air mass and minor proportion from inland. Additionally, the wind rose analysis demonstrated similar wind patterns. This suggests that longer range air masses and local winds influence are transportation pathway of particles that infiltrate indoors. In conclusions, this study revealed that peak concentrations of indoor PM2.5 and trace metals bound to PM2.5 pose a major health concern in households of low-income and informal settlements in the Western Cape, particularly Se, Cu, As and Pb. This study supports that monitoring the concentrations of potentially toxic elements in an indoor environment can be a useful tool for prevention and control of respiratory morbidity in children. Enforce stricter vehicle emission control measures, educating communities about natural air purification solutions, such as the use of specific indoor plants that effectively reduce PM2.5 levels, sensitize people on indoor pollution sources and the exposures they face, and the importance of ventilation. Increase the proportion of paved roads within the settlements, to minimize dust from unpaved surfaces. Promote vegetative cover in agricultural fields to assist as wind erosion breakers. Additionally, the municipality should host public awareness campaigns to educate communities about the outsources and how they can contribute to mitigation efforts. For future studies, it is recommended to extended monitoring periods, improved sensor calibration, duplicate filters, and improved fieldwork protocols to strengthen the reliability of findings and support more robust public health interventions. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2025-06-05T09:37:13Z 2025-06-05T09:37:13Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132379 Stellenbosch University xxii, 211 pages : illustrations (some color), maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Particles -- Environmental aspects Particulate matter -- Environmental aspects Air -- Pollution -- South Africa -- Measurement Environmental geochemistry Air quality -- South Africa -- Western Cape Environmental management -- South Africa -- Western Cape Urban ecology (Biology) -- South Africa -- Western Cape UCTD Gaoaaga, Kereemang Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa |
| title | Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa |
| title_full | Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa |
| title_fullStr | Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa |
| title_full_unstemmed | Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa |
| title_short | Geochemical characterisation and morphology of fine inhalable particles (PM2.5) in residential areas of the Western Cape, South Africa |
| title_sort | geochemical characterisation and morphology of fine inhalable particles pm2 5 in residential areas of the western cape south africa |
| topic | Particles -- Environmental aspects Particulate matter -- Environmental aspects Air -- Pollution -- South Africa -- Measurement Environmental geochemistry Air quality -- South Africa -- Western Cape Environmental management -- South Africa -- Western Cape Urban ecology (Biology) -- South Africa -- Western Cape UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132379 |
| work_keys_str_mv | AT gaoaagakereemang geochemicalcharacterisationandmorphologyoffineinhalableparticlespm25inresidentialareasofthewesterncapesouthafrica |