1. Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
2. Now at: Scion, Christchurch 8011, New Zealand
3. Department of Environmental Sciences, University of California Riverside, Riverside, California 92521, United States
4. Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, California 94720, United States
5. Atmospheric Chemistry Observations and Modeling, U.S. National Science Foundation National Center for Atmospheric Research, Boulder, Colorado 80301, United States