1/Possible #Airborne #SARSCoV2 Transmission through Air Ducts: after a series of infections, all 437 residents of an apt building were tested. 10 infections uncovered, all living on different floors but along two vertical lines with openings through their bathrooms

2/Ventilation shaft is located along each vertical line where shafts connect to units through blowhole in bathrooms. Units built before installation of exhaust fans w/backdraft dampers became compulsory. Thus, there's no physical block for air entering the room from the air duct.

3/"Our study also implies that the rigid rules of safe distancing that stick to droplet and contact transmission based on an outdated dichotomous notion of respiratory droplet or aerosols should be reconsidered" https://www.ijidonline.com/article/S1201-9712(20)32558-3/fulltext

4/visualization of the stack effect, showing the movement of air through buildings by @healthyheating https://twitter.com/healthyheating/status/1341268833181450240?s=19