Schoolteachers will be free to concentrate on teaching in their classes, children can behave normally - and take exams again in safety.  The Roboscientific Room Monitor will be as invisible in a classroom as an air conditioning unit.  It will be programmed to take air samples a regular intervals during the day - defined by the programme of class changes within the space.  So if a new group of pupils stay in the room for an entire morning of afternoon, it can sample the air shortly after everyone is settled in the room.  As long as there is no infection present in the room, nothing will happen, but if someone in there is emitting the invisible symptoms of Covid-19, the Monitor will detect it and alert the designated person within the school to take action - probably by isolating the class and organising individual tests.  

As an automated monitor of the space, like a smoke alarm, after the initial investment of the monitor, costs are minimal as the unit automatically purges and recallibrates after each testing session.  The sensors are expected to last for at least twelve months (experience in agricultural environments suggests over two years) with no maintenance regardless of the number of positive events discovered.