ABSTRACT
Since the first outbreaks of COVID-19, research has focused on how to minimize SARS-CoV-2 transmission indoors. SARS-CoV-2 has three identified transmission routes: (1) direct transmission of virus-carrying droplets between people in close proximity, by coughing, sneezing or talking; (2) indirect transmission via deposited, or transmitted, infectious droplets via surfaces; (3) airborne transmission through virus-carrying, small, airborne droplets, also called aerosols, emanating from infected individuals. To reduce direct transmission from large infectious droplets, physical distancing of individuals is promoted, and for indirect transmissions, the cleaning of surfaces, washing of hands and sneezing/coughing in the elbow are advocated. For people who need or tend to come close to (possibly) infected persons, personal protective equipment is used, including facemasks and gloves. For airborne transmission, the use of ‘proper’ ventilation measures has been recommended to decrease the risk. In this chapter, the background of airborne transmission research is outlined and measures to reduce transmission are discussed. It is concluded that to provide pathogen safe, and comfortable, buildings in the future, we are in urgent need of both a better understanding of how pathogens spread within buildings, and reliable and resilient new ways of ventilating indoor spaces that are flexible, affordable, efficient and effective.
