https://www.cnn.com/2020/04/30/opinions/eye-opening-south-ko...

The case study covers infections in a 19-story mixed commercial-residential building. First case was reported on March 9, 2020. The office seating diagram provided in the article shows extended (10 min or 1hr not sure), very close proximity spacing physically is the main reason for the spread.

Note that this was a call center so people were sitting and talking without masks on for extended periods.

* On March 9, one day after the first cases were reported, the entire building was closed. Testing was performed almost immediately on 1,143 people (workers, residents and a few visitors) with rapid results available to those affected and the team working to control the situation. The testing showed that 97 people (8.5% of those occupying the building) were infected. Most of the cases were women in their 30s and almost all (94 of the 97) worked on the 11th floor of the building, in the call center.*

I counted colored seats in the diagram and found 84 people in the call center got infected.

I think NYC got hit particularly hard because of subway cars. Enclosed in nearly airtight space for 10 - 30 minutes at a time.

I agree that everything is more crowded in NYC, but the only thing I can think of more crowded than a subway car is a nightclub. Estimating from ridership numbers, the average New Yorker rides the subway 15-30 minutes per day. The ceilings aren't even that high, just the number of people per unit volume is incredible.

One of the case studies I saw showed it spreading on a long distance bus between people sitting four rows away from each other.

That’s rush hour. Let’s not kid ourselves.