1. Department of Earth and Planetary Sciences; Harvard University; Cambridge MA USA
2. John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA USA
3. Department of Civil and Environmental Engineering; Massachusetts Institute of Technology; Cambridge MA USA
4. Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry; University of York; York UK
5. National Centre for Atmospheric Science, Department of Chemistry; University of York; York UK
6. Department of Chemistry; University of California; Berkeley CA USA
7. Department of Earth and Planetary Science; University of California; Berkeley CA USA
8. Atmospheric Chemistry Division; National Center for Atmospheric Research; Boulder CO USA
9. Division of Geological and Planetary Sciences; California Institute of Technology; Pasadena CA USA
10. Division of Engineering and Applied Science; California Institute of Technology; Pasadena CA USA
11. Cooperative Institute for Research in Environmental Sciences; University of Colorado Boulder; Boulder CO USA
12. Earth System Research Laboratory; National Oceanic and Atmospheric Administration; Boulder CO USA
13. Department of Atmospheric Science; Colorado State University; Fort Collins CO USA