Reducing Household Air Pollution and Improving Health in Nairobi’s Informal Settlements: A Participatory System Dynamics Approach

Abstract

Background/Aim: Rapid growth and unequal development has resulted in more than 60% of Nairobi’s population living in informal settlements. Household air pollution (HAP), primarily fine particulate matter (PM2.5), is a major contributor to the large environmental burdens of disease and mortality in these areas, but actions to reduce HAP exposure have so far had limited success. This pilot study is attempting to understand the problem as a complex, interconnected system and to assess the potential implications of different policy options. Methods: We used a participatory system dynamics approach to map the drivers and effects of HAP pollution in Nairobi’s informal settlements. The model was developed through a series of workshops with stakeholders (including community members, policymakers, NGOs, and academics), refined and calibrated to the Korogocho area of the city using available data, including recent trends in key variables. Expected impacts of changes in PM2.5 exposure on life expectancy were estimated within the model using life tables. Results: The system dynamics process identified key drivers of HAP exposure, such as outdoor air pollution levels, household ventilation and the proportion of households using clean stoves/lighting. Subsequent modelling revealed how these drivers interact and form important feedback loops in the system. Analysis of policy options suggests that combinations of policies may be more effective than single policies for reducing HAP exposure and improving health. In particular, the model highlighted the importance of awareness raising and investment in monitoring and health impact assessment, which can trigger reinforcing mechanisms to create synergies among policies. Conclusions: Despite limitations of the available data in this setting, the pilot study demonstrates the value that participatory system dynamics brings to understanding complex urban systems. It also indicates the importance of developing evidence-based health policy.