Background Global south faces detrimental impacts of climate change, particularly the escalation of extreme heat and the heightened prevalence of vector-borne diseases. Building-level risk mitigation strategies frequently exhibit synergistic or conflicting effects on the two-fold risk. This research investigates health risks posed by indoor heat and malaria transmission in Kisumu, Kenya, across 138 local residents and their thirty traditional rural settlements, which are examined in their original architectural forms and modified forms.
Methods This study introduces a coupled health risk assessment method, examining indoor heat stress and malaria transmission. It computes risk indices by evaluating exposure, vulnerability, and hazard, aligning with the IPCC’s risk assessment framework. The approach combines environmental monitoring data, computational fluid dynamics (CFD) simulations, and questionnaire surveys to analyze risk in homes, including factors related to the architectural designs and residents.
Findings Our findings suggest that traditional informal settlements with overcrowding issues, extensive cooking activities, and limited ventilation facilities significantly heightened indoor exposure and vulnerabilities. Four houses classified as having extreme high heat stress risk demonstrate indoor air temperatures where over 70% of the volume exceeds 30°C, and over 10% of the volume exceeds 35°C. Our results underscore the importance of roof-level ventilation by open eaves, which promotes natural airflow, disperses heat trapped near the ceiling, and improves indoor air circulation. Such intervention resulted in a considerable rise in the proportion of houses categorized as low to medium risk, with only two out of thirty houses remaining as high-risk homes. Moreover, the installation of windows has conflicting effects, facilitating heat mitigation and increasing the risk of mosquito entry. The adaptive schedules for opening kitchen windows and front-and-back-door design interventions can reduce the risks.
Interpretation Our research reveals a complex interplay of demographic and socioeconomic factors, occupancy behavioral adaptations, and architectural modifications as influential intervention factors in indoor thermal comfort and malaria disease transmission control. By addressing these architectural and behavioral adaptation aspects, our study contributes valuable insights into striking a balance of exposure and hazard risks in the context of vulnerable neighborhoods in Kenya.
Funding OODA Global Challenges Research Fund (GCRF) and Newton Consolidation Accounts Research Fund Award