Yes, 16 hours, and if you read further along in that thread, there's another expert that discusses the 6ft thing inside. It's not enough. And 25-50% capacity, doesn't seem to make a difference either without masks. So, for example, people in restaurants without masks on are talking, eating, laughing...without masks on. If someone is infected, the tiny aerosol droplets from their exhaled breath can hang in the air for up to 16 hours. And...the more they talk, exhale, etc, it just fills up that air in that room....and then you can suck that in. It's why we see such a correlation between indoor bars and restaurants....and a spike in infections.
All I can say is....I can't wait for the movie someone makes of this whole thing. It's insane.