Paul Whiteman, general secretary of school leaders' union NAHT, said:

"NAHT has been calling on the government to take action on ventilation in schools for some time and so we welcome this response - it is a much needed step in the right direction. 

"It is essential that this now becomes part of a comprehensive national strategy to ensure that every school and classroom is properly ventilated.

"We need to remember that identifying problems with ventilation, whilst absolutely necessary, are not the same as solving them. Where inadequate ventilation is identified, this needs to be addressed without delay, and the necessary resources provided. There is no escaping the fact that this is likely to require further investment from government. 

"Time is clearly of the essence here. The majority of schools will be returning in a matter of weeks, some sooner. We need these monitors to get into schools without delay so that classrooms can be made as safe as possible for everyone.

“We look forward to working with the DfE on the detail of how these devices can best be used to improve ventilation in classrooms.”