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Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools
Thesis (PhD)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867613933152501760 |
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| access_status_str | Open Access |
| author | Van der Walt, Rita Elise |
| author2 | Booysen, Marthinus J. |
| author_browse | Booysen, Marthinus J. Van der Walt, Rita Elise |
| author_facet | Booysen, Marthinus J. Van der Walt, Rita Elise |
| author_sort | Van der Walt, Rita Elise |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135680 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:44:01Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135680 Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools Van der Walt, Rita Elise Booysen, Marthinus J. Grobbelaar, Susara S. Rousseau, Pieter G. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Thesis (PhD)--Stellenbosch University, 2026. Van der Walt, R. E. 2026. Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/7e598d8b-a238-4ad5-9f8b-646359f435e8 The combined effects of climate change, infrastructure deficits, and energy poverty create a deteriorating feedback loop in South Africa, where poor indoor air quality and thermal conditions in school classrooms compromise the health, comfort, and cognitive performance of learners. This is amplified by a lack of long-term solutions with high-resolution data to quantify the environmental inequity between permanent (brick) and temporary (containerbased and prefabricated) classrooms, as well as a methodological gap in translating such data into actionable, low-cost interventions. These gaps are addressed through the development, deployment, and validation of an integrated, measurement-driven engineering framework that diagnoses climate-infrastructure vulnerabilities and informs evidence-based retrofit policies. A scalable, low-cost Internet of Things (IoT) sensing network was developed and deployed for 24 months across various classroom infrastructures, generating a novel public dataset of concurrent indoor environmental quality (IEQ) measurements. Observational analysis of this dataset quantifies the thermal and ventilation performance of each infrastructure type in relation to international standards. This provides the first quantitative evidence of worse thermal environments, characterised by more extreme temperatures and rapid fluctuations, in temporary infrastructures. In container classrooms, carbon dioxide (CO2) concentrations often exceed the thresholds associated with cognitive impairment, indicating poor ventilation. To diagnose the underlying causes, a novel framework is presented that applies a time-series, distribution-based global sensitivity analysis, specifically the Delta Moment-Independent Measure (DMIM), directly to measured data to derive effective thermal resistance-capacitance (RC) proxies without relying on physics-based parameters. The diagnostic framework successfully characterises brick classrooms as high-R, high-C structures with damped, delayed thermal responses. At the same time, temporary units are identified as low-R, low-C structures that respond sharply to external weather drivers. The framework’s infrastructure diagnostic utility is validated by its ability to characterise improvements in the RC dynamics of an uninsulated container classroom through a low-cost insulation retrofit. An exploratory analysis of household air pollution further demonstrates that thermal vulnerability drives occupant behaviours that degrade indoor air quality across socio-economic contexts. The core contributions of this dissertation form an integrated pathway from evidence to policy. This begins with an empirical foundation, consisting of a novel public dataset and scalable sensing methodology that produced it. An observational analysis of encountered IEQ conditions and their characterising against international benchmarks and metrics for comfort and cognition reports on exposures and how they differ among infrastructure types while accounting for the employed methods of heating, ventilation, and air conditioning (HVAC) in those classrooms and their impact on the indoor environment. A novel and model-agnostic framework for deriving RC proxies from measured data translates indoor temperature measurements into physical and actionable insights, providing information on the time-series influence of different climatic parameters on indoor temperatures, as well as the varying influences by infrastructure type. Finally, this dissertation translates these findings into tangible societal and scientific resources, including infrastructure-specific policy recommendations and a methodological enhancement to open-source scientific software. Through a replicable sensor-to-solution pathway, this dissertation transforms high-resolution data into policy-relevant insights and targeted engineering interventions to protect learner health and potential in resource-constrained environments. Doctoral 2026-04-07T14:00:09Z 2026-04-07T14:00:09Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135680 en Stellenbosch University 239 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Van der Walt, Rita Elise Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools |
| title | Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools |
| title_full | Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools |
| title_fullStr | Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools |
| title_full_unstemmed | Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools |
| title_short | Diagnostics of indoor environmental quality exposures and climate-infrastructure vulnerability in South African schools |
| title_sort | diagnostics of indoor environmental quality exposures and climate infrastructure vulnerability in south african schools |
| url | https://scholar.sun.ac.za/handle/10019.1/135680 |
| work_keys_str_mv | AT vanderwaltritaelise diagnosticsofindoorenvironmentalqualityexposuresandclimateinfrastructurevulnerabilityinsouthafricanschools |