1. Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
2. Aerosol and Haze Laboratory, University of Chemical Technology, Beijing 100029, P.R. China
3. IRCELYON, CNRSUniversity of Lyon, Villeurbanne 69626, France
4. Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm 11418, Sweden
5. Division of Nuclear Physics, Department of Physics, Lund University, Lund 22100, Sweden
6. Leibniz Institute for Tropospheric Research, Leipzig 04318, Germany
7. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, United States
8. Institut für Energie und Klimaforschung, IEK-8, Forschungszentrum Jülich GmbH, Jülich 52425, Germany
9. Institute of Physics, University of Tartu, Tartu 50090, Estonia
10. Aerodyne Research Inc., Billerica, Massachusetts 01821, United States
11. Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
12. Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
13. Department of Chemistry, University of Cøpenhagen, Cøpenhagen 2100, Denmark