1. Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
2. Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
3. Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington, DC, USA
4. Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
5. Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
6. Air Resources Division, National Park Service, Denver, CO, USA