Dispersion Modelling

Predicting air quality in a given scenario (for example a new development of land-use) and/or for a future year (forecasting) is undertaken using dispersion modelling. Dispersion modelling requires computer software and detailed data input to simulate the passage of an emission as it travels through the air until it reaches ground-level. It is a valuable tool for evaluating air quality impacts and exposure against national air quality standards and objectives.

Dispersion modelling can be used at the outset of a project to help inform the design process, once a scheme is finalised, and to investigate mitigation strategies.

Specific considerations of the local environment can be included within the dispersion model to ensure a detailed representation of a site is produced; these include building effects, local topography, and prevailing meteorological conditions.

Screening tools are often used as a simple method of calculating dispersion which enables a preliminary conclusion to be drawn on whether the contribution of one of more sources of pollution is insignificant or potentially significant based on simple data input.