The way viruses spread from human to human is being reevaluated by scientists and that may have an impact on future ventilation standards.
At the outset of the Covid-19 outbreak, the prevailing belief was that the virus was spread via droplets that quickly dropped out of the air. As researchers studied the virus, however, they realized that it was likely spread via aerosols—smaller, lighter particles that travel further than six feet and can linger in the air in poorly ventilated spaces.
Colds and flu have been thought to be primarily spread via droplets, as well, as they hold more viruses than aerosols. But studies have found that a smaller amount of influenza virus is needed to infect people when inhaled as aerosols rather than sprayed up the nose as saliva droplets.
If this view is correct, improved ventilation could greatly reduce transmission of colds and flu viruses as well as Covid. For this reason, some believe new minimum ventilation standards in buildings should be enacted especially when one considers some 12,000 to 61,000 people annually succumb to the flu.