Melanie Sarah Hammer^1,2, Aaron van Donkelaar^1,2, Randall Martin^1,2, Chi Li^1,3, Alexei Lyapustin⁴, Andrew M Sayer^4,5, Nai-Yung Christina Hsu⁴, Robert C Levy⁴, Michael J Garay⁶, Olga V. Kalashnikova⁶, Ralph A Kahn⁷, Michael Brauer⁸, Joshua Apte⁹, Daven K Henze¹⁰, Li Zhang¹¹ and Qiang Zhang^12,13, (1)Dalhousie University, Physics and Atmospheric Science, Halifax, Canada, (2)Washington University in St. Louis, Energy, Environmental & Chemical Engineering, St. Louis, United States, (3)University of California at Berkeley, Dept Chemistry, Berkeley, United States, (4)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (5)Universities Space Research Association Greenbelt, Greenbelt, MD, United States, (6)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (7)NASA/Goddard Space Flight Ctr, Greenbelt, MD, United States, (8)University of British Columbia, School of Population and Public Health, Vancouver, BC, Canada, (9)University of Texas at Austin, Austin, TX, United States, (10)University of Colorado Boulder, Boulder, CO, United States, (11)NOAA/ESRL, Boulder, CO, United States, (12)Department of Earth System Science,Tsinghua University, Beijing, China, (13)Center for Earth System Science, Tsinghua University, Beijing, China