Spatial variability of intraurban particulate air pollution: epidemiological implications and applications
Thesis DisciplineEnvironmental Sciences
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
The past twenty years of research that has associated air pollution with health outcomes has brought remarkable advance in statistical techniques that effectively tease out the intricacies of the relationship. However, while statistical techniques progressed, an assumption based on seminal work in the field persisted: that concentrations of particulate matter (PM) air pollution are spatially homogeneous within urban areas, and consequently, that personal exposures could be based on central monitoring site data alone. Although this assumption went unaddressed for years, it has now come to researchers' attention that it may be flawed and that the assumption may induce exposure misclassification error under certain conditions. This thesis explores intraurban spatial variability in PM through a systematic review of the literature, experimental field testing, modelling, and new methodological approaches. The key outcomes of the thesis are as follows: (i) the publication of the first systematic review of the intraurban particulate literature, challenging the widely-held assumption that PM concentrations are spatially uniform; (ii) an experimental test was conducted in Christchurch, New Zealand, revealing that the homogenous assumption was false for a city with high wintertime particulate matter concentrations; (iii) an integrated meteorological-emission model was evaluated for the first time at the intraurban level for PM and a new study design was suggested; and (iv) the spatial modification effect of social and ecological confounders was analysed with respect to respiratory hospital admissions and PM. Collectively, these outcomes provide a new body of knowledge informing researchers focused on assessing the relationship between air pollution and health in applications ranging from small-area exposure assessment to the wider field of environmental epidemiology.