1. Institute of Occupational, Social and Environmental Medicine, Center for Health and Society, Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany
2. Institute of Energy and Environmental Technology e.V., Duisburg, Germany
3. Federal Institute of Occupational Safety and Health, Dortmund, Germany
4. Center for Nanointegration Duisburg-Essen (CENIDE), University Duisburg-Essen, Duisburg and Essen, Germany
5. Department of Epidemiology, Lazio Region Health Service, Rome, Italy
6. Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden