Ventilation in Schools

Along with vaccinations, masks, physical distancing and proper hand hygiene, ventilation is another measure that can help prevent and slow the spread of COVID-19 in schools.

Thames Valley is making ongoing efforts to optimize air quality in classrooms and learning environments through improving ventilation and/or filtration. 

Parents and the community can be assured that all TVDSB schools will be operating within full compliance with all Ministry of Education and Public Health guidelines. 


Most TVDSB schools have full mechanical ventilation, which is routinely inspected and in good working order throughout the year. The frequency of the filter changes has been increased. In tandem with this, filter quality has also been improved where possible. Ventilation systems are also operated for extended hours, pre and post occupancy, to increase the daily air exchange. 

Thames Valley has invested more than $64.5 million to install or upgrade school mechanical ventilation systems over the last five years – with an additional $15 million in system improvements during the summer of 2021.   

By 2022, mechanical ventilation is expected to be installed at approximately 93 per cent of TVDSB schools.   

Understanding Ventilation Systems

Ventilation is the process of supplying or removing air from a space for the purpose of controlling the indoor air quality within the space. The types of ventilation systems commonly in use at TVDSB schools are:

  • Mechanical Ventilation – This is ventilation provided by motor-driven fans. These systems may include supply fans which push outdoor air into a building and exhaust fans which expel air out of a building.  These systems also condition the air through the use of heating and/or cooling equipment so that air is delivered to the space at comfortable temperatures. 
  • Passive Ventilation – This is ventilation delivered to the space primarily by air diffusion through doors, windows or other intentional openings in buildings, assisted by exhaust fans to draw fresh air into a building. 
  • Combined Ventilation – Schools that have had one or more additions built over time may have a combination of mechanical and passive ventilation systems. Passive ventilation would typically be found in older sections of a school while newer sections would most likely be served by mechanical ventilation systems.

View a list of Ventilation Systems at TVDSB Schools.

HEPA (High Efficiency Particulate Air) Filters

A mobile HEPA filter in a classroomMedical-grade, fan-powered HEPA filtration units have been shown to reduce the spread of airborne infections in health care facilities by removing viruses, bacteria and allergens as small as 0.3 microns from the air. 

The use of HEPA filtration units, in combination with improved ventilation strategies and existing health and safety protocols, work together to reduce the risk of COVID-19 transmission and support a safer environment for staff and students.

As of August 15, 2021, 1,405 HEPA filter units were in the process of being delivered and installed in Thames Valley schools.   

For schools with passive or partial mechanical ventilation, portable HEPA filtration will be installed in a variety of classrooms and other spaces.  

The HEPA filter units will be deployed to:  

  • Kindergarten classrooms in all 130 TVDSB elementary schools  
  • All classrooms with students with complex medical and physical needs  
  • All common areas (classrooms, libraries, gymnasiums, guidance offices, staff rooms, etc.) in schools without mechanical ventilation  

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