@turnipLeafgreen @joeyfox85 If people are really packed close together (not sure about Amtrak, but think busy subway), you need really, really high ACH compared to say, two people well separated in a large room. That's implied by tweet 5/7 of the thread. Trains are better than planes in this regard, I think
@turnipLeafgreen@joeyfox85如果人们真的挤在一起（不确定美铁的情况，但想想繁忙的地铁），你需要非常非常非常高的ACH，而不是两个人在一个大房间里分开。这一点在推特上得到了暗示。在这方面，我认为火车比飞机好