1. Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
2. Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, Villeurbanne 69626, France
3. Department of Environmental Science (ACES) & Bolin Centre for Climate Research, Stockholm University, Stockholm SE-106 91, Sweden
4. LUT School of Energy Systems, Lappeenranta, Lahti University of Technology (LUT), Lahti FI-15210, Finland
5. Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen-PSI 5232, Switzerland
6. Aerodyne Research, Inc., Billerica, Massachusetts 01821, United States