Mapping hotspots of environmental burdens in the framework of cumulative risk assessment in wallonia
Résumé
Differential exposure to multiple environmental burdens and benefits across populations with varying vulnerability can contribute heavily to health inequalities. Developing environment and health information systems has therefore become a major focus for public health. In this framework, the Scientific Institute of Public Service (ISSeP) works on building an integrated approach of environmental exposure assessment in the Walloon region, Belgium. This study develops an indexbased approach to assess the multiple environmental burdens at regional level and detailed local resolution that can be used in a spatial web tool. Indicators are based on environmental measure of pollutants in ambient air and soil, and on stressors for citizens related to noise and radon. Two methods were combined to identify both zones where pollutions and stressors are cumulating, even below threshold values, and zones where the exceedance of threshold values is frequent. First, a ratio value is calculated for each spatial unit (i.e. statistical sector) by dividing the indicator value by the corresponding threshold values quoted by the WHO or Walloon legal limit values. Other pollution sources (roads, industries, landfills, mine heaps, ...) are estimated by specific GIS processing based on Euclidean distance analysis which vary in relation to pollution effect to population. Secondly, environmental indicators are mapped as proportions of spatial units where the level of potential detrimental environmental factors exceeds the limit values. The spatial tool makes then possible the flexible and weighted combination of the normalized indicators, by computing online the resulting composite indicator. The approach developed in the present study will be compared to other case studies and their aggregation methods by focusing on results and the possible implications on planning interventions by the decision makers.