Luke Western¹, Jens Muhle², Paul B Krummel³, Matthew L Rigby⁴, Joseph R Pitt⁴, Jgor Arduini⁵, Chris R Lunder⁶, Simon O'Doherty⁴, Sunyoung Park⁷, Stefan Reimann⁸, Kieran M Stanley⁹, Martin K Vollmer⁸, Bo Yao¹⁰, Dickon Young⁴, Ben Adam¹¹, Minde An¹², Anita Ganesan¹³, Hsiang-Jui Wang¹⁴, Ray F Weiss¹⁵, Ronald G Prinn¹⁶ and Paul Fraser³, (1)Massachusetts Institute of Technology, Cambridge, MA, United States, (2)Scripps Institution of Oceanography, La Jolla, CA, United States, (3)CSIRO, Aspendale, Australia, (4)University of Bristol, School of Chemistry, Bristol, United Kingdom, (5)University of Urbino, Urbino, Italy, (6)Norwegian Institute for Air Research, Kjeller, Norway, (7)Seoul National University, Seoul, South Korea, (8)Empa, Duebendorf, Switzerland, (9)Tucson, AZ, United States, (10)Fudan University, Department of Atmospheric and Oceanic Sciences & Institute of Atmospheric Sciences, Shanghai, China, (11)University of Bristol, Bristol, United Kingdom, (12)Massachusetts Institute of Technology, Center for Sustainability Science and Strategy, Cambridge, MA, United States, (13)University of Bristol, School of Geographical Sciences, Bristol, United Kingdom, (14)Georgia Tech, Atlanta, GA, United States, (15)Univ California San Diego, La Jolla, CA, United States, (16)Massachusetts Institute of Technology, Center for Sustainability Science and Strategy, Cambridge, United States