Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA

Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA

now at: Department of Chemistry, Purdue University, West Lafayette, IN, USA

Chemical Sciences Division, Earth System Research Laboratory, National Oceanic & Atmospheric Administration, Boulder, CO, USA

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA

Droplet Measurement Technologies, Boulder, CO, USA

Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA

Droplet Measurement Technologies, Boulder, CO, USA

National Center for Atmospheric Research, Boulder, CO, USA

National Center for Atmospheric Research, Boulder, CO, USA

Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA

National Center for Atmospheric Research, Boulder, CO, USA

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA

Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA

Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA