The Nexus of Heat, Housing, and Health in Informal Settlements in Dar es Salaam, Tanzania

This study employs mixed methods involving geospatial and sensor technologies and quantitative data analysis to investigate the relationship between housing characteristics, heat perception, and self-reported health outcomes in an informal neighborhood in Dar es Salaam at both community and building scales.

We used a mixed-method approach, including a webGIS-based questionnaire administered during the hot season (December 2023 to February 2024). The questionnaire covered socio-demographic factors, heat perception, health outcomes, and housing characteristics. Concurrently, we collected heat index data in indoor spaces of 18 houses and one outdoor monitoring site using Kestrel heat stress monitors. Statistical analyses, including clustering, descriptive statistics, and ANOVA, were conducted on quantitative and qualitative datasets to establish relationships between housing characteristics, subjective and objective heat perception/exposure, and self-reported outcomes at building and community scales.

Heat monitoring data analysis revealed significant heat stress levels regardless of space and period. Outdoors, 60-70% of daytime and 5-25% of nighttime periods were categorized as "Hot" to "Extremely Hot." Indoors, 60-70% of daytime and 55-65% of nighttime periods were similarly categorized, regardless of housing typologies/material combinations. This persistent diurnal heat exposure resulted in adverse health outcomes such as muscle cramps, headaches, malaria, dizziness, and tiredness among others, as identified within the neighbourhood. Qualitative data analysis at the community level indicated distinct differences in housing characteristics and heat perception, emphasizing the importance of building-scale grey adaptation. The findings highlight housing conditions that limit residents' capacity to adapt to heat-related problems.

This study provides local evidence regarding the interrelationship between heat, housing, and the built environment. The data reveal disparities in heat perception and exposure in indoor spaces based on housing characteristics, underscoring the widespread housing-related vulnerability to heat stress.