The sensitivity of air pollution to the structure and design of cities

摘要

The importance of urban form in achieving sustainable environments has been recognised in the academic literature for some time. However, there has been rather limited progress in bringing such considerations into the urban systems planning forum. This may, in part, be due to our poor understanding of how large-scale features of urban morphology influence local environmental conditions. For example, the structure of cities, in terms of both their physical and socio-economic layout is likely to control the traffic demand and the resulting traffic flows around the road network. This may be anticipated to lead to spatial variability in the exposure of urban residents to transport associated pollution. However, most modelling work in this area has examined relationships under the constraints of the structure of real cities. As a consequence, the limited understanding we have of the manner by which different urban forms may be associated with total emissions and equity in pollution exposure may be context specific. This research is developing meso-scale urban transport models to examine the relationship between different aspects of urban form and air quality. Drawing upon urban theory, a number of classic forms of the road network are being studied under a range of socio-economic population scenarios. The research shows how vehicle flows and associated emission factors can be modelled under each scenario to determine the way in which aspects of urban structure are related to air pollution. An understanding of the manner by which structural characteristics govern such relationships will be critical if sustainability considerations are to be better incorporated into the urban planning process in the future.