What was the ventilation requirement for your school when it was designed? Have rates been measured this summer and repairs made (tighten fan belts, open dampers)? Have portable HEPA air cleaners been added to low-ventilated rooms? #SafeSeptemberON #onpoli 
Older schools with natural ventilation didn't necessarily achieve 30 CFM/person but it was certainly more than in the 1980s
That dip in the 1980's was a response to the energy crisis. It resulted in sick building syndrome. If smoking was present, outdoor air rates had to be 25 CFM/person, though good filtration with recirculation permitted reduced rates, the floor still being a mere 5 CFM/person.
Current ventilation practice (2004-present) is a bit different. For classrooms it's 10 CFM/person plus 0.12/sqft. Works out to about 14-15 CFM/person depending on room size and occupancy.
One temporary solution: reduce the number of occupants per room. This will provide proportionally more air outdoor air per person, with greater distancing and a smaller cohort.
As I'm writing these, @Sflecce has announced $50 million for Ontario school HVAC upgrades. Will be very eager to dig into the details. Hope to see mandatory measurements included.
Useful infographic 👍
