1. Laboratory for Air Pollution and Environmental Technology, Empa, Überlandstrasse 129, 8600 Dübendorf, Switzerland
2. Institute for Quantum Electronics, ETH Zürich, Wolfgang-Pauli-Str. 16, 8093 Zürich, Switzerland
3. Institute for Aerosol and Sensor Technology, FHNW, Klosterzelgstrasse 2, 5210 Windisch, Switzerland