A1. Droplets are ballistic projectiles, they infect by impacting on eyes, nostrils or mouth. They are > 100 um

Aerosols float in the air from tens of sec to hours, and they infect by inhalation. They are < 100 um

(5 um boundary is a long-standing error)

#LeapsChat @leapsmag https://twitter.com/leapsmag/status/1309191259697950721

A1(2): Some debate on twitter about what droplets exactly are. But clearly defined as ballistic projectiles that infect by impact. See this thread where I explained it in detail, or this image from a recent presentation of Deputy Director of ID at CDC
#LeapsChat @leapsmag

A1(3). And the thread that has all the gory details about the history and definition of droplets and aerosols is at:

https://twitter.com/jljcolorado/status/1307918933391933441

#LeapsChat @leapsmag