[Mako_Shark_Attack]

Sounds like the effects of tobacco smoke to me. Maybe the smoke is escaping from the teacher's lounge and causing this havoc? To ensure this doesn't happen again, ALL smoking must be banned in ALL schools, public and private.

[DonQ]

I kinda doubt it's tobacco smoke, simply because lots of these kids go home to parents who smoke and don't have symptoms there.

I suspect there is something related to the institutional nature of schools; these are schools in Virginia and northward, maybe it's because the buildings crank up the heat (drying heat) strictly according to the calendar without regard to the actual (uncommonly warm) weather, and that the sort of heating they have in school buildings is different (maybe drier, more stifling) than what they'd have at home.