| Principal Investigators |
| Principal Investigator | Institution |
| James A. Coakley, Jr. | Oregon State University |
| Paul J. Crutzen | Max-Planck Institute for Chemistry / Scripps Institution of Oceanography |
| Russell R. Dickerson | University of Maryland, College Park |
| Leo J. Donner | NOAA-Geophysical Fluid Dynamics Laboratory, Princeton University |
| Andrew J. Heymsfield | Meso and Microscale Meteorology Division, National Center for Atmospheric Research |
| Anand Inamdar | Scripps Institution of Oceanography |
| Jeffrey T. Kiehl | Climate and Global Dynamics Division, National Center for Atmospheric Research |
| Dieter Kley | Institute for Chemistry and Dynamics of the Geosphere, Forschungszentrum Juelich |
| Jos Lelieveld | Max-Planck Institute for Chemistry |
| Kimberly A. Prather | Department of Chemistry and Biochemistry, University of California, San Diego and Scripps Institution of Oceanography |
| V. Ramanathan | (C4 Director) Scripps Institution of Oceanography |
| Phillip J. Rasch | Climate Modeling Section, National Center for Atmospheric Research |
| Mark Thiemens | Natural Sciences, University of California, San Diego |
| Guang Zhang | Scripps Institution of Oceanography |