A Systems Dynamics Model of Urban Environmental Degradation and Public Health Linkages in Nigerian Secondary Cities

This dissertation develops and applies an original systems dynamics model of urban environmental degradation and its linkages to public health outcomes in Nigerian secondary cities, making a novel theoretical contribution to the understanding of feedbacks between environmental infrastructure provision, pollution levels, disease burden, and urban development dynamics. Secondary cities between 200,000 and one million population are the fastest-growing urban centres in Nigeria and will absorb a significant share of the country's urbanisation trajectory over the next twenty years, yet these cities receive far less research attention than megacities despite facing acute environmental engineering challenges. The theoretical contribution is a System Dynamics Urban Environmental Health Framework that models the feedback loops connecting population growth, water and sanitation infrastructure provision, solid waste management performance, air pollution from transport and generators, environmental contamination levels, disease incidence and mortality, workforce productivity, and fiscal capacity to invest in environmental infrastructure. The framework is operationalised for three Nigerian secondary cities: Aba in the South East, Ilorin in the North Central, and Gusau in the North West, using a combination of urban statistics, environmental monitoring data, health records, and expert elicitation to parameterise and calibrate the model for each city. Model validation uses historical data from 2005 to 2015 with scenario testing against the 2015 to 2022 period. Policy simulation is used to evaluate the environmental health co-benefits and dynamic long-term effects of alternative environmental infrastructure investment strategies. Original contributions include the systems dynamics model structure and the three city-calibrated model instances. Keywords: systems dynamics, urban environmental health, secondary cities, Nigeria, infrastructure investment.