Urbanisation Footprints and the Distribution of Air Quality in Nairobi City, Kenya
Various postulations on the relationship between urban morphology and air quality are qualitative. This fails to establish the strength of the contributions of each morphological parameter in the spatial distribution of the air quality. It is this gap in knowledge that this study sought to fill by modelling the correlation existing between the urban morphological variables of development density, land uses, biomass index and air quality values of Nairobi city. While 30 development zones of the city constituted the target population, IKONOS satellite imagery of the city for the year 2015 was utilised in establishing the development densities, land uses and biomass index. The parameters were transformed into numerical surrogates ranging from 1 to 10 with lower values accorded to zones with low biomass index, the highest development density, noxious land uses, high gaseous concentrations and vice-versa. Pearson’s correlation coefficients (r), coefficients of determination (R), t-tests and the Analysis of Variance (F-tests) with levels of significance being 95% were used to determine the strengths, significances and consistencies of the established relationships. The study established that development density is the most significant morphological variable influencing the distribution of air quality. This is followed by biomass index and to a weaker extent, land uses.
Keywords:Urbanisation, Urban morphology, Air quality, Development density, Land use, Biomass index
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