1. Centre for Environmental Sciences, Hasselt University, Hasselt, Belgium
2. Primary Health Care Centre GVHV, Genk, Belgium
3. Flemish Institute for Technological Research (VITO), Mol, Belgium
4. Belgian Interregional Environment Agency, Brussels, Belgium
5. Department of Public Health & Primary Care, Occupational & Environmental Medicine, Leuven University, Leuven, Belgium