Viable virus hangs in the air and on surfaces, just for us to come along.
Ω This time scientists measured viable virus, not just the RNA. The scale is log 10, so 1 is ten, 2 is a hundred, etc.
So in a small unventilated airspace hundreds of virus per liter of air just float about for 2 to 3 hours. Yikes, I have to get on a airplane next week!
We must assume that all hard surfaces in public places may have virus that is still viable for a few days after they were deposited. It is an unwelcome gift that keeps on giving.... disease.
Breaking the cycle is a very neighborly thing to do.