The Québec government and educational institutions are continuing to closely monitor the air quality in classrooms and ensure that appropriate mitigation measures are applied when problematic situations occur. 

The Ministère de l’Éducation has implemented a governance structure and is working closely with an independent expert in indoor air quality and industrial ventilation from the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST). This expert is assisting the Ministère in the development of a strategy regarding air quality in schools in order to ensure that the best possible learning and working environment is provided at all times for students and school staff.

Measures implemented

Some of the measures implemented are as follows: 

  • development of a new protocol for ongoing digital monitoring of air quality in classrooms and identification of the required technological solution
  • acquisition comfort parameter sensors to measure carbon dioxide (CO2) concentration, level of relative humidity and temperature to ensure optimal air quality in all classrooms in Québec  
  • installation of these sensors in all schools. It is, however, the responsibility of educational institutions to install them as quickly as possible, based on their plan and the dates on which the sensors are received.
  • implementation of a program for maintenance of ventilation equipment and windows in summer 2021
  • distribution and installation of several hundred air exchange systems within the school network
  • continuation of the program of required corrective measures to address problematic situations and adjustments to mechanical ventilation systems (that is, air evacuation systems and/or forced fresh air systems), such as:  
    • optimization of fresh air intake
    • removal of energy-saving measures
    • continuous operation of ventilation devices
    • replacement of air filters, use of more effective air filters if possible (MERV 13 or higher) and maintenance of ventilation systems, when required

The Ministère and the school network have been working together for several years and sharing their expertise to maintain good air quality in schools, especially by producing guides to best practices: 

The COVID 19 pandemic demonstrated the importance of continuously monitoring indoor air quality, especially in schools, and continuing to maintain safe environments for all occupants. 

Comfort parameter sensors

On September 10, 2021, the Ministère de l’Éducation announced that agreements had been reached with four companies, that is, Honeywell, Nova Biomatique, Assek Technologie and Airthings, which will supply the estimated 90 000 comfort parameter sensors that must be installed in all preschool, elementary, secondary, vocational training and adult general education classrooms in Québec.

This operation, currently underway, is intended to allow for close monitoring of air quality in all elementary and secondary schools as well as in vocational training and adult education centres. Québec is the first government in Canada to implement a program of this type.  

Indoor air quality and the comfort of students are influenced by multiple factors, such as CO2 concentration, temperature and the level of relative humidity. Scientific studies show that an elevated level of CO2 in indoor air may cause students to be uncomfortable and affect their concentration and results, much like when the ambient air temperature is too high, for example. 

Real-time readings of three comfort parameters (CO2 concentration, temperature and the level of relative humidity) allow school staff to make changes more gradually and quickly in the affected rooms by, for example, adjusting the inflow of outdoor air or completely air out a classroom during a break. 

Educational institutions can use the average data to take timely action when the set targets are not reached. 

School service centres and school boards can use the average data to identify trends and target buildings that require broader intervention plans and/or larger scale corrective work. 

This ensures that students and school staff are provided with best possible learning and working conditions in class.

The priority will be to install the sensors in classrooms with natural ventilation, meaning those that are not equipped with mechanical ventilation systems and where the windows and doors must be opened to ensure air exchange. 

It is the responsibility of educational institutions to install them as quickly as possible, based on their plan and the dates on which the sensors are received. 

The goal is to install these sensors in all Québec classrooms as soon as possible. 

The Ministère is working closely with the suppliers and the network to complete this large-scale project involving more than 3 600 buildings and 86 000 classrooms.

To learn more about CO2, see the Carbon dioxide (CO2) page. 

Progress of the installation of comfort parameter sensors

In total, approximately 90 000 comfort parameter sensors will be installed in classrooms in preschools, elementary and secondary schools, and in vocational training and adult education centres.

Of these, a little over 3600 are sensors that make it possible to read the parameters outside the buildings. Therefore, once the operation is complete, approximately 86 400 rooms will be equipped with comfort parameter sensors, in addition to the classrooms where sensors have already been installed. 

The sensors are installed in accordance with the established priorities:

  • Priority 1: Schools where CO2 concentrations over 2 000 ppm have been observed
  • Priority 2: Schools where CO2 concentrations over 1 500 ppm have been observed
  • Priority 3: Schools with natural ventilation
  • Priority 4: Schools with mechanical ventilation

As of May 13, 2022:

  • Number of sensors delivered by suppliers: 89 809 (100,0%)
  • Number of sensors in operation:1 76 596 (85,3%)

Sensors have been delivered to all schools where CO2 concentrations over 1 500 ppm or 2 000 ppm (priority 1 or 2) were observed. The delivery of sensors to schools with natural ventilation (priority 3) is nearly complete. Sensors will soon be delivered to schools with mechanical ventilation (priority 4).

The data will be updated as it becomes available.

Air exchangers

The Ministère has made available to school service centres, school boards and private educational institutions air exchangers that can be installed in classrooms where persistent air quality problems have been observed. Air exchangers are devices that filter out indoor air filled with CO2 and replace it with fresh air brought in from outdoors, thereby improving the indoor air.

Educational institutions are responsible for maintaining their classrooms and ensuring good air quality for students and staff. It is up to them to request an air exchanger from the Ministère. The devices are delivered as quickly as possible.

Total number of air exchangers delivered by the Ministère: 1132.

This data is usually updated on Mondays.

A multidisciplinary working group composed of scientific and technical experts was mandated by the Ministère de la Santé et des Services sociaux to study the issue of ventilation and the transmission of COVID-19 in educational and health care facilities. In its report published in January 2021, this group recommended that air purifiers not be used in classrooms, for the following reasons:

These devices are not, however, capable of countering the transmission of SARS-CoV-2 through close contact with an infected person, which is recognized as the principal mode of transmission.

Furthermore, when there is satisfactory ventilation, these devices are useless and even pose potential risks as they could impede the proper functioning of the ventilation systems in place.

Lastly, they could generate major air currents that could create problems such as spreading more air-borne particles over a longer distance and altering air flows if a mechanical ventilation system is already installed.

Carbon dioxide (CO₂)

CO2 is a natural product of human respiration. Its presence in educational institutions has no effect on the health of the occupants but can have an impact on their level of comfort. For many years now, the Ministère de l’Éducation has been paying attention to this comfort and air quality indicator in order to ensure a healthy environment for students and promote their educational success.

In outdoor air, CO2 comes from different sources, especially the combustion of fossil fuels, and the concentration fluctuates at around 400 ppm. Indoors, CO2 essentially comes from the air the occupants breathe out, and the concentration is over 400 ppm.

Normal concentrations of CO2 in indoor air may vary depending on occupancy density, room volume, type of activity carried out, length of occupancy and ventilation efficiency.

An average weekly CO2 concentration under 1 500 ppm may be used as an indicator of satisfactory ventilation and ensures good comfort for occupants (preventing situations where, for example, students feel drowsy and have difficulty concentrating).

The Regulation respecting occupational health and safety This hyperlink will open in a new window. prescribes a maximum of 5 000 ppm for an 8-hour working day and 30 000 ppm for a short 15-minute exposure. This maximum limit for exposure in the work location is recommended by the American Conference of Governmental Industrial Hygienists.

CO2 is a comfort parameter and one of the air quality indicators. An elevated CO2 concentration indicates that the air is stagnant. The rooms concerned may require ventilation, especially the intake of fresh air.

Air exchanges with the exterior by natural means such as opening the windows or through mechanical ventilation are the main contributors to reducing the concentrations of this non-toxic gas in occupied indoor spaces. Air exchange is therefore one of the first actions recommended if an elevated concentration is observed in a room.

Management parameters

To ensure good interior air quality in educational institutions, the following must be taken into consideration: 

  • An average daily CO2 concentration below 1 500 ppm may be used as a parameter of satisfactory comfort.
  • The optimal goal set for new buildings is an average daily CO2 concentration of under 1 000 ppm.
  • A relative humidity level varying between 30% and 50%, depending on the season.
  • An ambient temperature varying between 20°C and 24°C.

In its Document de référence sur la qualité de l’air dans les établissements scolaires du Québec This hyperlink will open in a new window. (available in French only), the Ministère de l’Éducation sets CO2 concentration levels at: 

  • 700 ppm more than the concentration in the outdoor air, which is around 400 ppm 
  • a maximum of 1 000 ppm for new buildings (constructed after 2016) 

The values measured in our classrooms and school buildings are well below these thresholds. The actions taken in the classrooms are mainly aimed at increasing the comfort levels of students and staff. 

Distinguish between carbon monoxide and carbon dioxide

It is essential to distinguish between these two gases, which have radically different effects on human health.

Carbon monoxide (CO): produced by incomplete burning of wood, hydrocarbons, etc., it is an odourless and colourless poison that can kill a human being, even in small quantities.

Carbon dioxide (CO2): produced by human respiration, it is a natural component of the air that poses no health risks at the concentrations normally found inside buildings.

Provincial data

Provincial dataWeek of March 21Week of March 28Week of April 4Week of April 25*
Number of schools concerned2 8732 9182 9262 956
Number of classrooms concerned69 61471 00371 21872 343
Average weekly CO2 concentration, from all active sensors880 ppm903 ppm846 ppm825 ppm
Number of classrooms with an average weekly CO2 concentration under 1 000 ppm50 577
(72,7 %)
49 478
(69,7 %)
54 494
(76,5 %)
57 178
(79,0 %)
Number of classrooms with an average weekly CO2 concentration between 1 000 and 1 500 ppm16 136
(23,2 %)
18 092
(25,5 %)
14 754
(20,7 %)
13 374
(18,5 %)
Number of classrooms with an average weekly CO2 concentration between 1 500 and 2 000 ppm2 821
(4,1 %)
2 979
(4,2 %)
1 779
(2,5 %)
1 623
(2,2 %)
Number of classrooms with an average weekly CO2 concentration over 2 000 ppm368
(0,5 %)
(0,6 %)
(0,3 %)
(0,2 %)
Average of the average weekly temperatures from all active sensors22 °C22 °C22 °C22 °C
Number of classrooms with an average weekly temperature under 20 °C1 835
(2,9 %)
2 442
(3,8 %)
1 402
(2,2 %)
1 301
(2,0 %)
Number of classrooms with an average weekly temperature between 20°C and 26°C61 253
(96,7 %)
61 744
(96,0 %)
62 807
(97,3 %)
64 039
(97,8 %)
Number of classrooms with an average weekly temperature over 26°C256
(0,4 %)
(0,2 %)
(0,5 %)
(0,2 %)

*Because the Easter break, which included a statutory holiday and several pedagogical days, occurred during the weeks of April 11 and April 18, 2022, the collated data for these weeks has not been published or taken into account for analysis purposes. It is not truly representative because the break reduced the number of students and staff present.

For the weeks presented, the provincial data shows that:

  • On average, more than 96% of rooms recorded an average weekly concentration of CO2 lower than 1500 ppm, which is a sign of satisfactory air quality. 
  • On average, less than 0.4% of rooms recorded an average weekly concentration of CO2 higher than 2000 ppm.
  • More than 96% of rooms had a satisfactory average weekly temperature (between 20°C and 26°C). 
  • Since the week of January 24, 2022, the data has been relatively stable from one week to the next, and the situation has improved slightly over the last week. 
  • The arrival of milder temperatures has had a positive impact on air quality during the week of April 4. 

Based on the provincial data, it can be concluded that our classrooms have satisfactory air quality. 

Go to the Provincial data – Archives page to follow the evolution of air quality in our schools.

Explanatory notes

The data used to calculate the weekly averages was recorded between 8 a.m. and 4 p.m., Monday to Friday. For the moment, the data management and analysis tools do not exclude from the calculations data for days on which the students were absent (pedagogical day, snow day, etc.). Accordingly, this data should be regarded as preliminary. Nevertheless, the necessary action is already being taken for classrooms where values higher than those expected have been measured.

More detailed and refined data that excludes the days on which the students are absent will soon be made available, once the suppliers complete their work on updating and fine-tuning the management and analysis tools.

According to our experts, this data is relevant and it is also encouraging.

For the moment, this data excludes that gathered from wired sensors because the number of sensors delivered and installed remains relatively low. It should be noted that, in total, there are fewer than 7 000 sensors (under 8%) in this situation and that the vast majority are in schools with mechanical ventilation systems that do not pose any problems.

The numbers published in the table include data from sensors that have been installed recently and are still in the breaking-in period.

However, the effect on the final results, whether upward or downward, remains marginal. CO2 concentration levels can fluctuate over the course of a day and from one day to the next. These fluctuations may be explained by various factors, including the outdoor temperature, which affects the opening of windows and doors, and the number of occupants in the room.

School staff know the instructions concerning the opening and closing of windows and doors, and regular reminders are sent out by the material resources departments.

Monitoring of educational organizations by the Ministère and publication of data

In order to provide information and transparency, the Ministère has made a commitment to update the provincial data at regular intervals. The data for previous weeks has been archived and can be consulted.

Educational organizations and private educational institutions are expected to make the data about their schools available. To consult this data, please contact them directly.

The Ministère strictly monitors educational organizations with rooms that have registered average weekly concentrations above 2 000 ppm. Solutions must be implemented by the educational organizations, which are responsible for managing and maintaining school buildings.

For classrooms with an average weekly CO2 concentration over 1 500 ppm, the educational organizations are encouraged to handle these situations by applying the established protocols in order to better manage the ventilation in these classrooms and maintain an acceptable air quality.

Status report on work completed and planned in the school service centres and school boards

Maintenance and upgrading work is being carried out continuously by educational organizations in order to provide healthy, comfortable and safe learning environments:

  • Since July 2020, $293 million has been spent on this work. Investments in the order of $225 million are planned for the coming year, for a total of $518 million. These amounts do not include the costs incurred by the Ministère to acquire hundreds of air exchangers and 90 000 comfort parameter sensors.
  • This work includes, among other things, the calibration of ventilation systems, the installation of air exchangers or implementation of other mechanical solutions, and the replacement or addition of windows that can be opened.
  • Ultimately, more than 35 000 rooms in 2 400 school buildings will have undergone this work.

On January 7, 2022, the Ministère sent the school service centres and school boards a request for information on the work performed with regard to ventilation between July 2020 and December 2021.The school service centres and school boards were also asked to provide information on the work planned between now and the end of 2022.

This procedure is intended to support the deployment of comfort parameter sensors and to help the Ministère ensure that the school service centres and school boards are taking action to improve the air quality in their buildings.

Highlights of the status report on the work

Based on the responses provided by the 72 school service centres and school boards that took part, the main findings are:

  • All of the school service centres and school boards have carried out appropriate work associated with air quality inside their buildings, with the exception of the Kativik Ilisarniliriniq School Board, which was unable to perform any of this work over the past year, mainly due to the COVID-19 restrictions in force throughout its territory.
  • All of the school service centres and school boards have planned or completed projects in connection with the air quality inside their buildings.
  • The work carried out by the school service centres and school boards has had an impact on more than 35 000 learning spaces in nearly 2 400 buildings.
  • Between July 2020 and December 2021, the school service centres and school boards invested $293 million in work to improve air quality.
  • The school service centres and school boards are planning to invest $225 million on ventilation over the course of 2022.

Summary table

The bilan des travaux réalisés et planifiés dans les CSS et les CS This hyperlink will open in a new window., available in French only, contains a summary table of the work completed and the work to be carried out, broken down into categories in accordance with the following parameters:

  • the number of school service centres and school boards that carried out work between July 2020 and December 2021
  • the number of school service centres and school boards planning to carry out work between January 2022 and December 2022
  • the total number of buildings and rooms affected during the two periods and the associated budgets

Three-party committee

A three-party committee (MEQ, CNESST-IRSST, MSSS-INSPQ) was created to oversee and authorize requests from the school system related to air quality and to ensure better coordination of the action taken in this regard by the Ministère and the educational organizations. It provides a high-level perspective in the area of health and safety in learning and work environments.


Ministère de l’Éducation 

  • M. Martin Bérubé, Interim Director, Direction de l’expertise et de l'innovation

Commission des normes, de l'équité, de la santé et de la sécurité du travail 

  • Mme Caroline Monette, Engineer, Direction de la prévention-inspection - Rive-Nord 

Institut de recherche Robert-Sauvé en santé et en sécurité du travail

  • M. Ali Bahloul, Researcher, Prevention of chemical, biological, mechanical and physical risks

Ministère de la Santé et des Services sociaux 

  • M. Christian Roy, Direction de la santé environnementale 

Institut national de santé publique du Québec 

  • Dr Stéphane Perron, Physician specializing in public health and preventive medicine
  • Dre Caroline Huot, Physician specializing in public health and preventive medicine 

[1] A sensor is considered to be in operation once it has been activated by the educational institution concerned and data is transmitted and collected by the suppliers.