Computational Modelling of Urban Pollution Dispersion
The dispersion of pollutants in an urban environment is largely determined by the pollutant emissions, the urban meteorology and the urban topography. A dominant feature of atmospheric dispersion is the stochastic nature of the process, which introduces limitations for deterministic mathematical predictions. Consequently many levels of mathematical modelling approaches have been developed, each appropriate for particular tasks. It has been found useful in the past to try to develop very simple models in order to scope out a problem prior to more detailed investigation. Frequently such very simple models are, nonetheless, directly useful in air quality studies and management.
In designing the first field tracer release experiment in DAPPLE it was necessary to estimate the link between the source release rate and the receptor concentrations (source-receptor relationship). Knowledge of this relationship allowed for correct receptor design and determination of optimum source release rates. Additionally and prior to any field or wind tunnel measurements some simple mathematical modelling was pursued for use in the design of the first field tracer experiment; a simple correlation for pollution dispersion in urban areas for use on the neighbourhood and city scales was developed, which can be found here
Cambridge is undertaking computational simulations relevant to the DAPPLE field campaigns using a suite of models of different complexity. Models (in increasing order of complexity) include:
- A Simple Correlation, developed by DAPPLE Cambridge team.
- Baseline Urban Dispersion Model, developed by Hanna, Britter, Franzese (2001).
- ASUDM
- UDM, developed by Dstl
- ADMS-Urban, developed by CERC Ltd
- FLUENT, developed by Fluent Inc.
Comparisons of the first DAPPLE field campaign results are now available with:
We are also running: UDM, ADMS-Urban and FLUENT for comparisons with the first DAPPLE field campaign.
We have begun to develop a scale-adaptive reactive pollutant dispersion model for urban areas, encompassing street, neighbourhood, city and regional scales in a consistent manner. The work appeared as a poster presentation in the 4th International Urban Air Quality Conference in Prague, March 2003 and a follow-up paper was submitted to Atmospheric Environment.
