Nobody knows anything for certain. We do not even have good data on mask effectiveness. The basis of all the restrictions is already a gut feeling/whim of the governors, not any concrete scientific data about what works and what doesn’t. Asking whether air conditioning system is good enough doesn’t make sense if we don’t even know what’s good enough. Nobody is doing any studies in that direction anyway, so we’ll never know.

I don’t know if lockdowns and restrictions make any practical difference or not, but people affected are definitely justified in complaining about large degree of arbitrariness in all of it. For example, NYC is still running subway and never stopped through all of it. Sure, people are relying on it to get places in New York, but so is everyone else in this country relying on their job to make a living, and yet many of their jobs were banned just like that.