INDIVIDUALS LIVING IN AREAS WITH HIGH BACKGROUND RADON - A GIS METHODTO IDENTIFY POPULATIONS AT RISK

Objective: to identify and link populations and individuals that live within high risk areas. Design: census registers and disease registers which contain data on individuals can only give aggregate statistics relating to postal code districts, town, county or state boundaries. H owever environmental risk factors rarely, if ever, respect these man-m ade boundaries. What is needed is a method to rapidly identify individ uals who may live within a described area or region and to further ide ntify the disease(s) occurring among these individuals and/or in these areas. Method: this paper describes a method for linking the standard registers available in Sweden, notably the residence-property address es they contain and the geographical coordinate setting of these, to m ap the population as a point coverage. Using standard GIS methods this coverage could be linked, merged or intersected with any other map to create new subsets of population. Representation of populations down to the individual level by automatised spatialisation of available cen sus data is in its simplicity a new informatics method which in the de signated GIS medium adds anew power of resolution. Results: we demonst rate this using the radon maps provided by the local communes. The Swe dish annual population registration records of 1991 for the county of Ostergotland and the property register available at the Central Statis tical Bureau of Sweden formed the main data sources. By coupling the a ddress in the population register to the property register each indivi dual was mapped to the centroid of a property. By intersecting the pop ulation coverage with the radon maps, the population living in high, n ormal or low risk areas was identified and then analysed and stratifie d by commune, sex and age. The resulting tables can be linked to other databases, e.g. disease registers, to visualise and analyse geographi cal and related patterns. The methodology can be adapted for use with any other environmental map or small area. It can also be expanded to the fourth dimension by linking likewise available migration informati on to generate immediately coordinate-set, accumulated exposition and similar data; (C) 1997 Elsevier Science Ireland Ltd.