A multi-scale modelling system for the urban atmospheric environment

Prerequisites of a sustainable urban environment include tolerable temperature, humidity and wind and low air pollution. However, the structure and material of the built environment impacts on the local climate and often has an adverse effect on pollution levels. In this paper we present high spatial resolution models of urban meteorology and air quality that can be used both for planning purposes and for forecasting episodes. The models are based on the widely used ADMS system for atmospheric dispersion and include allowance for building structure and fabric, street canyons and surface wetness. They can be used as advanced sub-grid scale models for mesoscale numerical models and can also be used with smart devices, for instance, for the for issuing of alerts or for the incorporation of crowd soured data. Examples of the application of the models in London, Lecce in Italy and Hong Kong will be presented, including comparisons with measured data and the ENVI-met numerical model. The extent to which the horizontal length scales of cities affect urban air quality and temperature perturbations will be discussed in the context of rapidly expanding cities.