The following scientists reviewed the document: Jonathan Abbatt, John Adgate, Alireza Afshari, KangHo Ahn, Francis Allard, Joseph Allen, Celia Alves, Meinrat O. Andreae, Isabella Annesi-Maesano, Ahmet Arısoy, Andrew P. Ault, Gwi-Nam Bae, Gabriel Bekö, Scott C. Bell, Allan Bertram, Mahmood Bhutta, Seweryn Bialasiewicz, Merete Bilde, Tami Bond, Joseph Brain, Marianna Brodach, David M. Broday, Guangyu Cao, Christopher D. Cappa, Annmarie Carlton, Paul K. S. Chan, Christopher Chao, Kuan-Fu Chen, Qi Chen, Qingyan Chen, David Cheong, Per Axcel Clausen, Ross Crawford, Derek Clements-Croome, Geo Clausen, Ian Clifton, Richard L. Corsi, Benjamin J. Cowling, Francesca Romana d'Ambrosio, Ghassan Dbaibo, Richard de Dear, Gianluigi de Gennaro, Peter DeCarlo, Philip Demokritou, Hugo Destaillats, Joanna Domagala-Kulawik, Neil M. Donahue, Caroline Duchaine, Marzenna R. Dudzinska, Dominic E. Dwyer, Greg Evans, Delphine K. Farmer, Kevin P. Fennelly, Richard Flagan, Janine Fröhlich-Nowoisky, Manuel Gameiro da Silva, Christian George, Marianne Glasius, Allen H. Goldstein, João Gomes, Michael Gormley, Rafal Górny, David Grimsrud, Keith Grimwood, Charles N. Haas, Fariborz Haghighat, Michael Hannigan, Roy Harrison, Ulla HaverinenShaughnessy, Philippa Howden-Chapman, Per Heiselberg, Daven K. Henze, Jean-Michel Heraud, Hartmut Herrmann, Philip K. Hopke, Ray Horstman, Wei Huang, Alex Huffman, David S. Hui, Tareq Hussein, Gabriel Isaacman-VanWertz, Jouni J.K. Jaakkola, Matti Jantunen, Lance Jennings, Dennis Johansson, Jan Kaczmarczyk, George Kallos, David Katoshevski, Frank Kelly, Søren Kjærgaard, Luke D. Knibbs, Henrik N. Knudsen, GwangPyo Ko, Evelyn S.C. Koay, Jen Kok, Nino Kuenzli, Markku Kulmala, Kazukiyo Kumagai, Prashant Kumar, Kazumichi Kuroda, Kiyoung Lee, Nelson Lee, Barry Lefer, Vincent Lemort, Xianting Li, Dusan Licina, Chao-Hsin Lin, Junjie Liu, Kam Lun E. Hon, John C. Little, Li Liu, Janet M. Macher, Ebba Malmqvist, Corinne Mandin, Ivo Martinac, Dainius Martuzevičius, Mark J. Mendell, David Miller, Claudia Mohr, Luisa T. Molina, Glenn Morrison, Roya Mortazavi, Edward Nardell, Athanasios Nenes, Mark Nicas, Zhi Ning, Jianlei Niu, Hidekazu Nishimura, Colin O'Dowd, Bjarne W. Olesen, Paula J. Olsiewski, Spyros Pandis, Daniel Peckham, Tuukka Petäjä, Zbigniew Popiolek, Ulrich Pöschl, Wayne R. Ott, Kimberly Prather, Andre S. H. Prevot, Hua Qian, Shanna Ratnesar-Shumate, James L. Repace, Tiina Reponen, Ilona Riipinen, Susan Roaf, Allen L. Robinson, Yinon Rudich, Manuel Ruiz de Adana, Masayuki Saijo, Reiko Saito, Paulo Saldiva, Tunga Salthammer, Joshua L. Santarpia, John H. Seinfeld, Gary S. Settles, Siegfried Schobesberger, Paul T. J. Scheepers, Max H. Sherman, Alan Shihadeh, Manabu Shiraiwa, Jeffrey Siegel, Torben Sigsgaard, Brett C. Singer, James N. Smith, Armin Sorooshian, Jerzy Sowa, Brent Stephens, Huey-Jen Jenny Su, Jordi Sunyer, Jason D. Surratt, Kazuo Takahashi, Nobuyuki Takegawa, Jørn Toftum, Margaret A. Tolbert, Euan Tovey, Barbara J. Turpin, Annele Virtanen, John Volckens, Claire Wainwright, Lance A. Wallace, Boguang Wang, Chia C. Wang, Michael Waring, John Wenger, Charles J. Weschler, Brent Williams, Mary E. Wilson, Armin Wisthaler, Kazimierz Wojtas, Douglas R. Worsnop, Ying Xu, Naomichi Yamamoto, Xudong Yang, Hui-Ling Yen, Hiroshi Yoshino, Hassan Zaraket, Zhiqiang (John) Zhai, Junfeng (Jim) Zhang, Qi Zhang, Jensen Zhang, Yinping Zhang, Bin Zhao, Tong Zhu.

Understanding the transmission of respiratory infections indoors requires expertise in many distinctly different areas of science and engineering, including virology, aerosol physics, flow dynamics, exposure and epidemiology, medicine, and building engineering, to name the most significant. No one person has expertise in all these areas. However, collectively, the community of the signatories to the Comment understands the characteristics and mechanisms behind the generation of respiratory microdroplets, survival of viruses in the microdroplets, transport of the microdroplets and human exposure to them, and the airflow patterns that carry microdroplets in buildings. We have dedicated our careers working in this multidisciplinary field, and our statement stems from our collective expertise spanning the entire field.

No