The school has conducted retro commissioning of the mechanical ventilation systems in each of our buildings to verify that all teaching spaces meet the NYC Department of Buildings mechanical code for ventilation. In spaces that have ducted supply and return HVAC fresh air, supply and room exhaust is through that system. In those rooms that have an exhaust only system and use windows as the fresh air source, teachers will be asked to open windows immediately upon entering the room and maintain them in an open position in order to introduce outside air into classroom spaces.