The length of time a virus can survive in an aerosol is not yet well established and depends largely on the time it takes for the virus-laden aerosol to travel and the decay of the virus density during transmission. If a patient coughs, droplets can travel up to about 6 m and sneeze up to about 8 m. These droplets can remain in the air for about 10 minutes. When the liquid in the droplet gradually evaporates to a diameter of about 5μm, often only the pathogen itself remains, which is then called the droplet nucleus, and can stay in the air for a longer period of time, and can even be spread farther with the air flow. If the virus does not die in the process of droplet evaporation, it is still active, and the virus will be adsorbed on the droplet nucleus and spread. When the droplet nucleus is formed by evaporation of water, the virus survives for a short period of time due to the elevated salt concentration. However, when evaporation is complete and the droplet nucleus is formed, the virus attached to the nucleus dies more slowly and survives for a relatively long time. Ultraviolet light has a killing effect on the virus, and the virus will survive for a shorter period of time in sunlight. Therefore, extra care should normally be taken in unventilated confined spaces, and the virus will survive for a longer period of time in poorly ventilated environments, and the risk of being infected is higher if the exposure time is long enough. Source: Dr. Yurai