Sarah Woods, National Center for Atmospheric Research, Boulder, United States, Sara Lance, University at Albany State University of New York, University at Albany, Atmospheric Sciences Research Center, Albany, United States, Jose D. Fuentes, Penn State University, University Park, United States, Kerri Pratt, University of Michigan Ann Arbor, Department of Chemistry, Ann Arbor, United States, William R Simpson, University of Alaska, Geophysical Institute and Department of Chemistry and Biochemistry, Fairbanks, United States and Paul B Shepson, Purdue University, Departments of Chemistry, and Earth, Atmospheric, and Planetary Sciences, West Lafayette, IN, United States