This guide describes how to reduce the risk of far-field airborne transmission of COVID-19 through improved ventilation. The guide is based on the most current data and scientific guidance available at the time of writing (December 2021). This guide applies to all healthcare facilities and should be used by infection, prevention, and control (IPC) and facility managers.  Ventilation is a process by which a portion of outdoor air is supplied into and extracted from an indoor space for the purposes of diluting and removing indoor contaminants.