1. Laboratory for Air Pollution/Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
2. Department of Chemistry and Applied Biosciences, ETH, Swiss Federal Institute of Technology, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland
3. Laboratory for Gas Analysis, METAS, Federal Institute of Metrology, Lindenweg 50, 3003 Bern-Wabern, Switzerland
4. Department of Environmental Modelling, Sensing & Analysis, TNO, Organisation for Applied Scientific Research, Westerduinweg 3, 1755LE Petten, The Netherlands