CERC is the principal developer of the urban version of the Atmospheric Dispersion Modelling System (ADMS-Urban). This model is designed for practical use running interactively with Geographical Information Systems and it includes such features as the effects of complex terrain and buildings and allowance for short term fluctuations. Application to the urban environment has been achieved by inclusion of algorithms to estimate traffic emissions from traffic flow details, a street canyon model based on OSPM developed by NERI and a chemistry model. The model provides a very flexible platform for validation of a range of model parameterisation and improvements arising as a result of the study (e.g. more complex street architecture, calm wind conditions, roof level flow).
Although significant effort and considerable funding has been and is being expended in the development of models for urban dispersion and in the obtaining of experimental data sets to improve and validate the models, far less effort has been expended on providing formalised procedures for model validation and thus frequently the validation becomes an unstructured and arbitrary comparison of disparate bits of information. This gives little or no guidance to users including regulatory authorities on the quality (fitness for purpose) of the models.