Airborne Transmission of Virus-laden Aerosols

When people carry out expiratory activities, such as speaking, singing, coughing or simply breathing, aerosols can be generated and exhaled into the environment. These exhaled aerosols may contain pathogens (viruses or bacteria) if produced by an infected individuals. 

Virus-laden aerosols, once released into the environment, can suspend in air for prolonged period of time and travel to longer distance. If inhaled by a potential host, they can enter deeper into the lower respiratory tract to initiate a new infection. Airborne transmission has been found in most respiratory diseases and has been confirmed to be the major transmission mode responsible for the spread of COVID-19.