Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca, México

Center for Aerosol and Cloud Chemistry, Aerodyne Research, Billerica, MA, USA

Cooperative Institute for Research in the Environmental Sciences (CIRES) and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA

now at: ETH, Zurich, Switzerland

Center for Aerosol and Cloud Chemistry, Aerodyne Research, Billerica, MA, USA

Department of Earth and Atmospheric Sciences, Saint Louis University, Saint Louis, MO, USA

Cooperative Institute for Research in the Environmental Sciences (CIRES) and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA

Center for Aerosol and Cloud Chemistry, Aerodyne Research, Billerica, MA, USA

Molina Center for Energy and the Environment, La Jolla, CA, USA

Earth Atmospheric and Planetary Sciences Department, Massachusetts Institute of Technology, Cambridge, MA, USA

Cooperative Institute for Research in the Environmental Sciences (CIRES) and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA