I believe it is more a function of driving people indoors into close proximity with each other. Also the kids going back to school the darling little petri dishes! (yes I love kids and think they should be in school. they are also very good at spreading germs)
From what I understand airborne poisons (gas, spores, aerosols) are more concentrated in indoor environments. If virus is attached to dust or droplets, it would likely follow a similar pattern.