1. Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
2. Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, United States
3. Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20742, United States
4. Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, United States
5. Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States