A spatial decision support system to allow the investigation of the impact of emissions from major point sources under different operating policies

A Spatial Decision Support System (SDSS) is being developed for Her Majesty's Inspectorate of Pollution (HMIP). It enables the investigation of the spatial implications of different operating procedures from large point sources of pollution. The environmental effect of emissions is assessed using the critical loads methodology developed at ITE and modelled deposition footprints. This approach allows an effect per unit emission or pollution potential to be determined for each source. Individual sources are modelled and included within the SDSS if their current emissions are above a given threshold. The SDSS provides a graphical user interface (GUI) which facilitates a fast, efficient and effective means to specify and to examine the effect of different operating policies. Mapping, statistical and optimization facilities are provided to help describe the effect of any specified strategy. Maps may be produced as deposition rates or exceedance values. Statistics may be visualised as histograms and scatter plots. The optimization facility uses linear programming to minimise the total environmental impact (estimated from emissions and critical loads) or maximise power produced within environmental limits. The SDSS has been written in the Arc/Info Macro Language (AML) and provides an invisible interface with standard GIS facilities and programmes written in C.