Toronto District School Board
Skip to main content

Ventilation in Schools

Ventilation is one strategy to help reduce the number of contaminants in the air and improve indoor air quality.

Please download the TDSB's ventilation report to learn more about the Board's ventilation strategies and recent investments , as well as details on the ventilation systems and strategies for each school.

The TDSB has focused on several areas to improve ventilation in schools and keep students and staff healthy.

Filtering the Air

  • Maintaining approximately 16,000 institutional-grade HEPA units in TDSB schools to enhance air cleaning in every occupied classroom, portable, and resource room, as well as other instructional spaces that do not have mechanical ventilation (library, cafeteria, and gymnasium.)
  • Maintaining frequent and regular filter changes in existing ventilation system throughout the school year.
  • Specifying MERV 13 filters for any new mechanical equipment Existing Mechanical equipment has the highest MERV rated filter that its design will allow.

Ensuring Heating, Ventilation and Air Conditioning Settings are Maximizing Ventilation

  • Caretaking staff check that the mechanical system is functioning in the building and submit service notifications to Maintenance staff when there is an issue.
  • Maintenance staff respond to work notifications and undertake repairs, including preventive maintenance checks, of the mechanical systems.
  • Adjusting the operating schedules for all mechanical systems to increase the amount of air exchanges per day in the building. 
  • Setting the systems to run at increased outside airflows during the school day whenever possible, further improving air exchange rates.
  • Ensuring that where possible, indoor spaces receive three to six equivalent air changes per hour (ACHeq). Air exchange rates vary per building, based on many factors. Equivalent air changes include the contribution of natural infiltration and HEPA filter units.

Maximizing Outdoor Air

  • Encouraging schools to open windows for short periods of time throughout the day to increase ventilation and bring in natural fresh air.
  • Promoting and supporting classes, activities and lunches to be held outside where possible.

Addressing Local Projects to Improve Ventilation

  • Although there is no building code or legislative requirement to install CO2 monitoring devices in individual classrooms, the TDSB is installing CO2 sensors and occupancy sensors on new ventilation equipment, to monitor fresh air delivered to the school and occupancy levels. This program is closely coordinated with Building Automation Systems (BAS) upgrades and new installations, and the recommissioning of ventilation system controls.
  • TDSB Health and Safety webpage provides principals and caretaking staff with a process to report and follow up on an Indoor Air Quality concern. This procedure follows Ontario Occupational Health and Safety regulations and guidelines, as well as ASHRAE or Health Canada guidelines, where applicable.

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 TDSB has nearly 600 schools that use a variety of ventilation systems; the complexity and reach of the ventilation systems in each building varies with the age of the school and subsequent additions. The types of ventilation systems commonly in use 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 filtered and delivered to the space at comfortable temperatures.
  • Passive Ventilation – This is ventilation, also called non-mechanical or natural ventilation, delivered to the space primarily by air infiltration through doors, windows or other openings in buildings. In TDSB schools, motor driven exhaust fans are often used to induce infiltration, drawing fresh air into a building.
  • Combined Ventilation – Also called partial mechanical 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.

To learn more about the ventilation system in each TDSB school, please download the Excel Ventilation Report, and select individual schools from the pull-down menu list.

HEPA (High Efficiency Particulate Air) Filters

Regardless of the ventilation system(s) in use at a school, all TDSB classrooms have been equipped with medical-grade, fan-powered HEPA filtration units. HEPA filters are clinically proven 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 airborne contaminants such as respiratory viruses and smoke particles, and support a safer environment for staff and students.

HEPA units will remain in schools for the 2024/2025 school year. School administrators and Caretaking staff have been provided with guidelines regarding the care and use of the HEPA units, as well as the process to report and replace any non-functioning units. Units are inspected over the summer months and filters are replaced as per manufacturers guidelines.