Ambient Air Pollution and Population Health in the Navrongo Health and Demographic Surveillance Site

Abstract

Summary This thesis broadly highlights the magnitude of the health burden attributable to air pollution and examines the exposure pathways and intervention sustainability in rural northern Ghana. CHAPTER 1 introduces the global and local significance of air pollution as a leading environmental health risk, particularly in Sub-Saharan Africa where populations face a dual burden of household and ambient pollution. The chapter outlines critical evidence gaps regarding mortality burdens across the life course, specific cardiometabolic pathways, and the sustainability of clean cooking interventions. It presents the conceptual framework linking these gaps to the study's three research objectives and describes the unique research platform of the Navrongo Health and Demographic Surveillance System (NHDSS). CHAPTER 2 investigates the relationship between early-life exposure to ambient PM₂.₅, household fuel use, and under-5 mortality in the NHDSS. The analysis demonstrates that while early-life ambient PM₂.₅ showed no significant association with mortality, household use of unclean cooking fuels was associated with a 73% higher mortality risk. This finding establishes household air pollution as a critical determinant of child survival in this setting. CHAPTER 3 extends the mortality analysis to adults, examining associations between cooking fuel type, ambient PM₂.₅ exposure, and all-cause and cause-specific mortality. The use of unclean cooking fuels was associated with 53% higher all-cause mortality, 76% higher non-communicable disease mortality, and 74% higher cardiovascular mortality. The findings reveal the substantial contribution of household air pollution to adult mortality amidst Sub-Saharan Africa's epidemiological transition. CHAPTER 4 examines the epidemiological association between long-term PM₂.₅ exposure and components of cardiometabolic disease in an adult Ghanaian cohort. The analysis reveals a specific association with hypertension but not with overall metabolic syndrome or its non-hypertensive components. The population attributable fraction indicates that 18.6% of hypertension cases may be attributable to PM₂.₅ exposure in this population. CHAPTER 5 evaluates the long-term adoption and barriers to sustained use of improved cookstoves distributed in prior interventions. The study reveals substantial disadoption rates three years post-intervention, with economic factors (fuel costs, stove breakage) and cooking preferences identified as primary barriers. These findings highlight the implementation challenges in transitioning households to clean cooking technologies. CHAPTER 6 provides a general discussion that synthesizes the key findings, methodological considerations, public health implications, and directions for future research. The discussion emphasizes the primacy of household air pollution in this rural setting, the life-course perspective on exposure effects, the specificity of the hypertension pathway, and the complex reality of intervention sustainability. The chapter argues for integrated strategies that combine environmental and clinical approaches to reduce air pollution's health burden. It also concludes with an impact section outlining the scientific and societal contributions of the research, highlighting how the thesis provides novel longitudinal evidence from a well-characterized African cohort, strengthens the case for prioritizing household energy transitions, and offers implementation insights for designing more effective clean cooking interventions in similar settings across Sub-Saharan Africa.