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 Ma jesty's Inspectorate of Pollution (HMIP). It enables the investigation of the spatial implications of different operating procedures from la rge 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 p er unit emission'' or ''pollution potential'' to be determined for eac h source. Individual sources are modelled and included within the SDSS if their current emissions are above a given threshold. The SDSS prov ides a graphical user interface (GUI) which facilitates a fast, effici ent and effective means to specify and to examine the effect of differ ent operating policies. Mapping, statistical and optimization faciliti es are provided to help describe the effect of any specified strategy. Maps may be produced as deposition rates or exceedance values. Statis tics may be visualised as histograms and scatter plots. The optimizati on facility uses linear programming to minimise the total environmenta l impact (estimated from emissions and critical loads) or maximise pow er 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 ''.