There was an article yesterday (I think) where Japan found out that there was a handful of people who got sick via air conditioning circulating in a restaurant where a Covid+ person was also eating. They weren't close enough to the Covid+ person to pick it up normally, so they speculate it traveled via the HVAC system.
If that's true (and theoretically it makes plenty of sense), then areas with high population density and a lot of people living in condos and apartments would be hardest hit (Italy, NYC, China, etc.).
It also would explain why Texas and Florida are largely staying quiet and without crisis, despite huge populations and the fact that it's very apparent to me that we are not really following social distancing guidelines that well. At least not as well as some other places with worse situations have been.