https://nypost.com/2020/08/22/air-conditioned-rooms-help-spread-covid-19-research-shows/
Air-conditioned rooms help spread COVID-19, research shows
In more humid rooms, virus droplets become heavier and fall faster in higher humidity, “providing less chances for other people to breathe in infectious viral droplets,” the team wrote, according to DW, a German news website.
Dry air makes the droplets shrink and hang around, becoming what the scientists describe as an “optimal route” for transmission.
Low humidity also dries out mucous membranes in the nose, making an easier way in for the coronavirus, they wrote.