Abstract
The global rise in forcibly displaced populations, driven by conflicts, natural disasters, and the escalating impacts of climate change, has led to prolonged encampments in low-quality shelters. These shelters often exhibit poor thermal regulation, inadequate ventilation, and unvented cooking, exacerbating poor indoor air quality (IAQ). Such conditions significantly increase risks of respiratory diseases, airborne infections, and mortality, particularly among vulnerable groups, including children, the elderly, and individuals with pre-existing health conditions. This thesis reviews the shelter design process for systematically deliver adequate ventilation and IAQ, through case studies in Japan and Ethiopia, aiming to improve health outcomes through evidence-based shelter design. It addresses four key research questions.What is the impact of shelter design on the health of displaced populations, and how has it been measured? A systematic bibliometric analysis revealed that prolonged exposure to poor IAQ and extreme indoor temperatures are critical environmental factors affecting health, particularly through their association with infectious diseases. Self-reported data and building simulations dominate the methodologies, yet there is a lack of clear, transdisciplinary guidance linking shelter design to health. The review identified gaps in metrics and evaluation methodologies, highlighting the need for more robust, evidence-based frameworks for assessing shelter quality.
What is the influence of occupant behaviour on the natural ventilation and airborne transmission risk in shelters? A novel, low-cost monitoring methodology was developed and tested in temporary housing in Kumamoto Prefecture, Japan, after the 2020 floods. Self-assessed behavioural data, coupled with mathematical disease transmission models, revealed that CO2 concentrations exceeded national thresholds 70% of the time, correlating with insufficient ventilation rates below the required 8.5 Ls-1p-1. This led to a predicted COVID-19 transmission risk of 60–80%. The study emphasises the need of including occupant behaviour in shelter design and presents a transferable methodology for assessing ventilation and disease transmission risks.
To what extent can simplified airflow models inform shelter design on opening sizing for adequate ventilation? Using shelters in Hitsats camp (Ethiopia) as a case study, the Warren equations were identified as the most suitable simplified model following a comparative and performance-based review of available analytical and empirical models for natural ventilation. These equations were then compared with more advanced simulations in Contam and EnergyPlus. The results showed a 94–99% agreement in design decisions for window sizing across both buoyancy-driven and wind-driven scenarios. This highlights the reliability of simplified airflow models as an accessible and accurate alternative for non-engineering teams, enabling the optimisation of shelter ventilation without compromising precision.
How can the shelter design process be improved to account for healthy ventilation and IAQ? A ventilation modelling tool was co-developed with 42 volunteers among NGOs, humanitarian workers, and academics. Validated with data from Ethiopia, Djibouti, and Nepal, this tool integrates 20 inputs and data from 3100 global locations to predict ventilation rates, IAQ, and COVID-19 transmission risks within 10–30 minutes. Designed for non-specialists, the tool is the first of its kind to be co-developed with intended users, demonstrating its potential to improve health outcomes in emergency settings and guide policy by ensuring practical, scalable, and evidence-based solutions for humanitarian agencies.
This research provides actionable insights for global shelter design, advancing both policy and practice. By addressing the gaps in metrics, methodologies, and design frameworks, it enables the creation of healthier, more sustainable shelter environments for displaced populations. Policy implications include the adoption of simplified modelling tools for rapid assessments, the integration of occupant behaviour into design guidelines, and the prioritization of health-focused standards in humanitarian shelter policies. Recognising the exacerbating role of climate change in displacement, this work calls for climate-resilient shelter designs that mitigate risks and protect vulnerable populations from preventable health issues during prolonged displacement.
| Date of Award | 19 Feb 2025 |
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| Original language | English |
| Awarding Institution |
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| Sponsors | McIntyre Scholarship in Healthy Housing & The Great Britain Sasakawa Foundation |
| Supervisor | David Coley (Supervisor), Daniel Fosas (Supervisor), Tristan Kershaw (Supervisor) & Alexander Copping (Supervisor) |