1. Department of Atmospheric Science Colorado State University Fort Collins CO USA
2. Leverhulme Centre for Climate Change Mitigation, Department of Animal and Plant Sciences University of Sheffield Sheffield UK
3. Department of Environmental Sciences and Engineering University of North Carolina at Chapel Hill Chapel Hill NC USA
4. Department of Environmental and Occupational Health The George Washington University Washington DC USA
5. Department of Civil and Environmental Engineering Massachusetts Institute of Technology Cambridge MA USA
6. Department of Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology Cambridge MA USA