Spatial modelling of feedback effects between urban structure and traffic-induced air pollution - Insights from quantitative geography and urban economics

Urban air pollution is among the largest environmental health risk and its major source is traffic, which is also the main cause of spatial variation of pollution concerns within cities. Spatial responses by residents to such a risk factor have important consequences on urban structures and, in turn, on the spatial distribution of air pollution and population exposure. These spatial interactions and feedbacks need to be understood comprehensively in order to design spatial planning policies to mitigate local health effects.
This dissertation focusses on how residents take their location decisions when they are concerned about health effects associated with traffic-induced air pollution and how these decisions shape future cities.
Theoretical analytical and simulation models integrating urban economics and quantitative geography are developed to analyse and simulate the feedback effect between urban structure and population exposure to traffic-induced air pollution. Based on these, spatial impacts of policy, socio-economic and technological frameworks are analysed.
Building upon an empirical exploratory analysis, a chain of theoretical models simulates in 2D how the preference of households for green amenities as indirect appraisal of local air quality and local neighbourhood design impact the environment, residents' health and well-being.
In order to study the feedback effect of households' aversion to traffic-induced pollution exposure on urban structure, a 1D theoretical urban economics model is developed. Feedback effects on pollution and exposure distributions and intra-urban equity are analysed. Equilibrium, first- and second-best are compared and discussed as to their population distributions, spatial extents and environmental and health implications.
Finally, a dynamic agent-based simulation model in 2D further integrates geographical elements into the urban economics framework. Thus, it enhances the spatial representation of the spatial interactions between the location of households and traffic-induced air pollution within cities. Simulations contrast neighbourhood and distance effects of the pollution externality and emphasise the role of local urban characteristics to mitigate population exposure and to consolidate health and environmental effects.
The dissertation argues that the consideration of local health concerns due to traffic-induced air pollution in policy design challenges the concept of high urban densification both locally and with respect to distance and advises spatial differentiation.