1. Helmholtz Zentrum München – German Research Center for Environmental Health, Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Neuherberg/Munich, Germany;
2. Helmholtz Center Munich – German Research Center for Environmental Health, Institute of Epidemiology 2, Neuherberg/Munich, Germany;
3. European Commission, Joint Research Centre, Directorate F – Health, Consumers and Reference Materials, Ispra, Italy