Airborne Transmission of SARS-CoV-2: Evidence and Implications for Engineering Controls

Since late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally, causing a pandemic (coronavirus disease 2019, or COVID-19) with dire consequences, including widespread death, long-term illness, and societal and economic disruption. Although initially uncertain, evidence is now overwhelming that SARS-CoV-2 is transmitted primarily through small respiratory droplets and aerosols emitted by infected individuals. As a result, many effective nonpharmaceutical interventions for slowing virus transmission operate by blocking, filtering, or diluting respiratory aerosol, particularly in indoor environments. In this review, we discuss the evidence for airborne transmission of SARS-CoV-2 and implications for engineering solutions to reduce transmission risk.