3 September 2025
hc

Winter is approaching, which often means we prefer to keep the windows in the workplace closed to keep out the cold. However, this can pose a problem for indoor air quality. In enclosed spaces without sufficient ventilation, harmful substances accumulate more quickly, including the CO2 we exhale. Too high a concentration of CO2 can lead to fatigue, loss of concentration, and even health complaints such as headaches and dizziness.

Good ventilation is crucial to keep the air fresh and healthy and can help limit the spread of diseases. It is a legal obligation according to the welfare at work code. An alternative to a well-functioning mechanical ventilation system is opening windows and doors for fresh air, which is a simple and effective way to refresh the air in your workplace. Ventilation and airing are most effective; an air purification system is a last resort that you can install if the first two options are not possible. Be careful to purchase air purification devices that actually work and that you know what you are buying.

How do you know if the air quality is still sufficient, especially if the outdoor air is cold and you want to keep windows open to a minimum?

Portable CO2 meters as a tool

A convenient solution to monitor air quality in the workplace is the use of portable CO2 meters. These small, mobile devices measure the amount of carbon dioxide (CO2) in the air and indicate when the concentration becomes too high. The meters provide real-time insight into air quality, so you know exactly when additional ventilation or airing is needed.

How does it work? A CO2 meter measures the amount of CO2 in the air, which is an important indicator of air quality. When the CO2 level exceeds the recommended limit of 900 ppm (parts per million) is reached, it's time to provide extra ventilation or airing to the room. Especially in spaces where people are together for extended periods, such as offices, meeting rooms, or workshops, the CO2 level rises quickly if there is insufficient air supply.

Not sure which device to choose? Then follow the recommendations from the Practical Guide for Air Quality Meters from the FPS Public Health; because there are also bad devices available on the market!

```html <p class="mb-0">co2</p> ```

Maintenance of CO2 meters

Also, don't forget that these CO2 meters need to be maintained. To ensure that the CO2 meter continues to provide accurate data, regular maintenance is of great importance. Here are some tips:

  • Calibration: CO2 meters must be calibrated periodically. This ensures that measurements remain accurate. Depending on the model and manufacturer, it is recommended to calibrate the meter once a year or every two years. Be sure to check the operating instructions.
  • Cleaning: Ensure that the ventilation openings of the meter are free of dust and dirt. This can affect measurements and shorten the lifespan of the meter. A simple cleaning with a soft cloth may be sufficient.
  • Check batteries: For portable meters, it is essential to check the batteries regularly. Low battery voltage can affect the operation of the device. So make sure you always have spare batteries at hand or charge the meter regularly.

Air purification systems

As mentioned earlier, it is advisable to purchase air purification systems only when mechanical ventilation or traditional ventilation are not possible. To help you with your choice, you can use the Practical guide for choosing an air purification system | Federal Public Service Health. In this guide, the Federal Public Service Health refers to a database of recognized air purification systems.

Currently, this database contains only one manufacturer, which is not an accurate reflection of reality. There are indeed multiple devices on the market that meet the government's criteria. However, devices are only included in the list when manufacturers themselves submit an application for recognition; therefore, over time, the list will be supplemented with other devices and manufacturers.

Last but not least

Since November 6, 2022, the "indoor air quality law" exists in Belgium, which has been drawn up to improve air quality in publicly accessible enclosed spaces (e.g., cafes, restaurants, sports halls, theaters, etc., these are not yet precisely defined in the legislation). Homes and office meeting rooms do not fall under this law.

The law has four main objectives, which will only become enforceable after the publication of royal decrees (RD):

From 1/10/2024, the following provisions can be applied on a voluntary basis. Only from 2027 will these become mandatory.

  • use at least 1 CO2 meter per room;

  • perform a risk assessment and, if necessary, draw up an action plan; and

  • at the request of the public, provide information on the current or expected air quality in the location.

  • Codex on well-being at work (and the standards included therein on air quality by means of CO2 concentration thresholds and ventilation rates), applicable to everyone who employs workers.

  • Legislation on product standards (air purification systems and CO2 meters), applicable when placing these products on the market.

The exact places/sectors where this obligation will apply will only be defined later in a Royal Decree (not yet published). This will happen in phases, but eventually, all enclosed places accessible to the public will fall under these obligations (target date: 2037).

Other legal provisions that are already applicable:

  • Codex on well-being at work (and the standards included therein on air quality by means of CO2 concentration thresholds and ventilation rates), applicable to everyone who employs workers.

  • Legislation on product standards (air purification systems and CO2 meters), applicable when placing these products on the market.