Edited by Renyi Zhang, Texas A&M University, College Station, TX, and accepted by Editorial Board Member John H. Seinfeld March 3, 2021 (received for review September 9, 2020)Airborne transmission arises through the inhalation of aerosol droplets exhaled by an infected person and is now thought to be the primary transmission route of COVID-19. By assuming that the respiratory droplets are mixed uniformly through an indoor space, we derive a simple safety guideline for mitigating airborne transmission that would impose an upper bound on the product of the number of occupants and their...…Edited by Renyi Zhang, Texas A&M University, College Station, TX, and accepted by Editorial Board Member John H. Seinfeld March 3, 2021 (received for review September 9, 2020)Airborne transmission arises through the inhalation of aerosol droplets exhaled by an infected person and is now thought to be the primary transmission route of COVID-19. By assuming that the respiratory droplets are mixed uniformly through an indoor space, we derive a simple safety guideline for mitigating airborne transmission that would impose an upper bound on the product of the number of occupants and their...WW…