Acknowledgements
Hatice Koca Akdeva, Department of Public Health and Community Medicine, University of Gothenburg, and Hans Nymand Pedersen, Aarhus University Hospital, are acknowledged for analysing PExA and EPC-samples, respectively. We thank Duncan Sutherland, iNANO Center, Aarhus University, for making Scanning Electron Microscope images and Joakim Pagels, Ergonomics and Aerosol Technology, Lund University, for his assistance in calculating particle mass concentrations derived from SMPS-data. Access to the NMR spectrometers at the Danish Center for Ultrahigh-Field NMR Spectroscopy (Ministry of Higher Education and Science grant AU-2010-612-181) is gratefully acknowledged. We particularly thank the participants for being a part of the study. The Climate Chamber Group includes Peter Ravn, Vibeke H. Gutzke, Kirsten Østergaard, and Ole Dam.