I feel I should follow this up to provide a little context here. I'm a custodian at a high school. Specifically, one that shows up after everyone leaves and cleans everything up. So if you have kids, the person cleaning their school all night might have covid and forced to do it anyway.

Well if you're going in when the kids have had all day to fill the air ..at least they probably won't stop you wearing a mask (like they do to teachers). By the time the kids come back in the morning anything you breathed out should be dead though.