Impact on health



Air purifiers

The Law of 6 November 2022 for the improvement of indoor air quality

Impact on health

What effects does poor indoor air quality have on health?

In one of its publications, the Superior Health Council lists the most frequently reported health problems associated with poor air quality.

They include:

  • respiratory symptoms,
  • fatigue,
  • allergies,
  • irritation of the mucous membranes,
  • irritation of the eyes,
  • skin irritation,
  • headaches,
  • dizziness.

International research also links exposure to poor air quality with a number of diseases such as:

  • asthma (and asthma symptoms);
  • lung cancer;
  • cardiovascular disease (CVD);
  • upper and lower respiratory tract infections/symptoms;
  • acute poisoning.

(IAIAQ, 2011).


What is ventilation? And why is it important?

Ventilating a room allows its air to be constantly replaced.

Natural ventilation involves leaving the doors or windows open to allow air to circulate inside the building, and some of the indoor air to be replaced by air from outdoors.

Mechanical ventilation requires the installation of a ventilation system that pumps outdoor air inside the premises or building and/or removes indoor air at the same time. This kind of system can be installed either in a specific place (toilet, for example), or throughout the building (automatically controlled system).

Whether natural or mechanical, ventilation helps to dilute the contaminants that may be present in the air inside buildings; these could be microorganisms, bacteria or chemical pollutants such as fine particles or volatile organic compounds, for example.

What is the difference between ventilation and aeration?

Ventilation is the process through which "clean" air (normally outdoor air) is intentionally and continuously fed into an indoor space, while stale is removed. This can be done through natural or mechanical means.

Aeration is the natural process through which indoor air is replaced by outdoor air when doors or windows are open, for a short period of time.

How can ventilation stop the spread of viruses?

When we breathe, speak, cough or sneeze, we emit a larger or smaller amount of water droplets in the air we exhale. If we are infected by viruses or microbes, these droplets are loaded with them.

The largest drops fall very quickly onto surfaces and the ground, but can contaminate people in close proximity, which is why it is important to maintain a certain physical distance between people, wear a mask and respect barrier gestures.
The finer drops or micro-droplets, on the other hand, remain suspended in the air for several hours; these are called "aerosols".

In a room, these aerosols gradually spread throughout the space. Their diffusion is comparable to that of perfumes or cigarette smoke.

The higher the concentration of aerosols in a room, the higher the risk of contamination.

Thanks to ventilation, the outdoor air combines with the aerosol-laden indoor air, which reduces the concentration of aerosols in the room, and thus the risk of contamination by the bio-pollutants (such as viruses) that the aerosols are likely to contain. This makes it possible to limit the risk of serious respiratory diseases.

Are there any threshold values above which the air is decontaminated?

There is no threshold value for ventilation rate, air change rate or CO2 concentration above which the risk of contamination by viruses or other types of pollutants can be excluded.

The more intense and regular the ventilation, the lower the risk.

This is why we must strive to achieve a CO2 concentration rate indoors that is comparable to that of the outdoor air (i.e. approximately 400 ppm).

A room is considered well ventilated if the CO2 concentration is less than 900 ppm (or 500 ppm above the outdoor concentration).

In practice, if the ventilation or purification flow rate is 40 m³/hour per person, an adult engaged in gentle activity will almost never exceed 900 ppm (or 500 ppm above the outdoor concentration).

This air ventilation or purification rate corresponds to the World Health Organization (WHO) recommendations and is also contained in the Code of Well-being at Work.

This minimum ventilation rate must be higher for intense activities, since the production of CO2 and the production of aerosols (and therefore the breathing of these aerosols) are then higher. It must also be higher if the number of people present increases, or if the nature of the activities is itself a source of pollution (for example, by producing fine particles).

Is ventilation a good idea in these times of high energy prices?

Energy consumption remains an important point of attention.  Maintaining a CO2 concentration in indoor air below a threshold of 1,200 ppm and a minimum ventilation rate of 25 m³/h, for example, does not result in a large increase in consumption PROVIDED that the ventilation rate is adapted to the number of people in the room and/or the CO2 concentration measured.

From an energy point of view, it is beneficial to have, if possible, a system with heat recovery and a demand control system. The demand control system automatically increases and decreases the ventilation rates depending on whether there are more or fewer people in the room and therefore depending on the CO2 concentration measured by the CO2 meter. Heat recovery involves the use of a heat exchanger built into the ventilation system that can achieve an efficiency level of 80% or more.

These concepts were explained in more detail during the kick-off meeting of the Indoor Air Quality Platform on 12 October 2022.

Are there any quality criteria for ventilation systems?

There are no specific technical or quality requirements for ventilation systems. It is recommended that the system be tested on delivery to check that the intended rate is achieved.

In the context of the Covid-19 pandemic, marketing criteria have been determined for air purification systems but not for mechanical ventilation equipment.

However, attention should be paid to the equipment's acoustics, as it is important to avoid "cutting off" the mechanical ventilation (or air purification) in the rooms because the noise is considered excessive. However, if the facility has to be shut down, it is important to monitor the CO2 concentration to ensure that it remains as low as possible, preferably below the recommended limits (below 900 ppm if possible and not exceeding 1,200 ppm). If the CO2 concentration exceeds these thresholds, it is strongly recommended that the ventilation system be reactivated to limit the risk of contamination.

CO2 meters

What is a CO2 meter? Is it the same thing as a CO2 sensor or an indoor air quality meter? ​

A CO2 meter is a device that measures the concentration of CO2 in a given space.
All these names designate the same type of device, with the distinction that an indoor air quality meter does not just focus on measuring CO2, but can also measure other air quality criteria, such as the concentration of fine particles in the air.

Why is it useful to measure CO2 in indoor spaces? 

Measuring the concentration of viral particles in the air is complicated. CO2, which we also emit when we breathe, is much easier to detect and measure. The concentration of CO2 in indoor air depends mainly on the number of people in the room, the physical activity taking place there and the effective ventilation rate.

Measuring the concentration of CO2 in the air is a good indicator of the ambient air quality in an enclosed space; a high concentration of CO2 shows that the ventilation is insufficient in this space. As the air exhaled by the people present is loaded with aerosols (microdroplets produced by respiration) that can be contaminated with microorganisms, bacteria or viruses, a high concentration of CO2 in a room is therefore an indicator that the air quality is probably not good.

To maintain healthy air quality and reduce the risk of being contaminated by aerosols, it is necessary to aerate and ventilate to replace the air in enclosed spaces.

A high concentration of CO2 in an enclosed space does not necessarily mean that the air is loaded with viruses. Measuring the CO2 level makes it possible to detect reference thresholds above which the air in the room should be replaced or an air purification device should be used.

Ideally, the CO2 rate in the air should not exceed 900 ppm (or a maximum of 1,200 ppm). Some scientific studies have shown that above a concentration of 1,000 ppm, CO2 has effects on human performance (particularly intellectual performance) and that it is preferable to remain below this threshold.

The natural CO2 concentration of the outdoor air is an average of 400 ppm. Ideally, it should be close to this threshold in enclosed spaces.

CO2 meters measure the CO2 content of a room. They do not act as a ventilation or aeration device.

What are the legal requirements for a CO2 meter?

From 22 March 2024, the marketing of these devices  is subject to certain criteria, under the law on product standards [FR, NL]. These new criteria will steer the market towards more reliable CO2 meters and ensure better monitoring of indoor air quality. They are set out in the Royal Decree of 7 February 2024 [FR/NL].
Before placing a CO2 meter on the market, the manufacturer or the person responsible for placing the CO2 meter on the market must have these criteria tested and measured by an accredited laboratory.

Are all CO2 meters concerned?

No, only portable and transportable CO2 meters. In other words, devices that can be easily transported from one place to another (whether or not they are specifically designed for this purpose), and that can be used during transport.

Is this royal decree retroactive?

No, all appliances placed on the market before 22 March 2024 do not have to meet these conditions.

How to choose a CO2 meter? What should I look out for?

To choose a CO2 meter that is both suitable and easy to use, we recommend that you take a number of factors into account:

  • The type of device: Choose a sensor that actually measures CO2.
  • The possibility of calibration, i.e. the possibility of adjusting the sensor to compensate for measurement errors that appear over time: Choose a sensor with automatic calibration or with manual calibration based on measurement of the outside air. Avoid devices that require a laboratory to be calibrated.
  • Measurement range: Choose a measurement range of at least 2000 ppm and, if possible, up to 5000 ppm.
  • Measurement error: A sensor, like any measuring device, has a measurement error. This is the difference between the measurement result and the actual value. A maximum error of less than or equal to 10% of the measurement up to 2000 ppm is considered acceptable.

For more advice, you can continue to refer to the federal recommendations drawn up as part of the Covid-19 pandemic, over:

Where is it preferable to install (a) CO2 meter(s)?

Ideally, the unit should be installed:

  • in a prominent and central location;
  • at least 1.5 m from people because the air they breathe out can influence the measurements.

It should not be placed:

  • next to a door, window or other opening that is open frequently or for long periods of time;
  • near the ventilation system air intake.  

It is also advisable to start by monitoring the areas in which the air quality is potentially less good, i.e. in the corners of a room, near the air extraction point (if there is one), in areas where there is the highest density of people, etc.

How do I know if my CO2 meter is measuring correctly?

Do some preliminary tests before using your CO2 meter.
Place the appliance outdoors or near an open window. The concentration of CO2 outdoors is between 400 and 500 ppm. This concentration is higher in towns than in the countryside.

  • If your device measures a value well below 400 ppm or well above 500 ppm, report it to the person responsible for monitoring indoor air quality (management, prevention advisor) or contact the supplier or manufacturer.
  • If your device measures a value of around 400 to 500 ppm, then your CO2 meter is working properly.

Don't forget to calibrate your equipment regularly, in accordance with the manufacturer's instructions.


Air purifiers

What is an air purification system?

An air purification system captures and/or inactivates the contaminants (microorganisms, fine particles, etc.) present in the air. It provides air that is decontaminated and, therefore, purified of pollutants (such as fine particles).

 There are two main categories of devices based on:

  • capture: capture of particles that potentially contain viruses or bacteria (HEPA filter, electrostatic precipitation);
  • inactivation: damage to all or some of the microorganisms in an air stream, so that they can no longer multiply or propagate (e.g. UV-C).  

Why is the use of an air purifier recommended?

The use of air purification systems, in addition to ventilation and limiting sources of pollution, further reduces the risk of contamination. 

In some places, it may be easier to install an air purification system because installing a ventilation system would require major renovation work. Air purification systems reduce the presence of certain pollutants. Their use is therefore recommended as a way of significantly improving indoor air quality, pending the possible installation of a ventilation system at a later date. Air purification is therefore an option for ensuring healthier indoor air by reducing the pollutants present.

If I use an air purifier, do I also need to install a ventilation system?

Affordable air purification systems do not currently eliminate the many indoor air pollutants with the same efficacy, which means that a minimum level of ventilation remains necessary. This minimum is set at 25 m³/hr per person by both the CODEX (if the sources of indoor air pollution are controlled) and by the Law of 6 November 2022 on improving indoor air quality in closed spaces accessible to the public.

Technically, it would be possible to work only with an air purification system, but that requires strict monitoring of the pollution sources and good installation. Such installations currently only exist in certain fields, such as space travel.

Why install a purification system if it does not lower CO2 concentrations?

The use of this type of device makes it possible to purify indoor air and improve its quality. Clean air guarantees a lesser presence of biological contaminants (moulds, bacteria and viruses) and possibly also chemical contaminants (particles, formaldehyde that can be released from furniture or floor coverings, etc.). See on this subject: Indoor air pollution: we are all exposed to it!

Aerating, ventilating, purifying and treating the air help limit the spread of these contaminants as explained in the short video by the SPF Employment: Ventilate - YouTube.

The measurement of the CO2 concentration is an indicator of air quality, but CO2 is not a contaminant in itself.

Which air purification systems are authorised?

From 18 May 2024, criteria will apply to the marketing of air purification systems that use technologies capable of effectively eliminating aerosols from contaminated air or deactivating viruses. These criteria are set out in the Royal Decree of 9 February 2024 [NL/FR].

This legislation provides users with an additional guarantee of the quality of the air purification systems on the market that combat viral aerosols. Thanks to a recognition label awarded to each recognised air purification system, users can easily identify devices whose high effectiveness against viral aerosols and safety have been recognised by the FPS. A list of all recognised air purification systems will also be published on the FPS website.
Are all air purification systems that combat viral aerosols affected?

No, only systems with an efficiency equivalent to that of class E12 (99.5%), H13 (99.95%) filters, or higher.
In addition, systems used for medical purposes fall outside the scope of this Royal Decree.

How can I find out if an air purifier has been recognised by the FPS?

You can find out whether a purification system has been recognised by the FPS :

  • by looking for the following pictogram on the appliance packaging and/or on the online sales website.
    The first recognition labels will be visible from early summer 2024. 
  • by consulting the list of recognised purification systems.
    This list will be published on this site from the summer of 2024, and updated regularly.

Do I have to buy an air purification system recognised by the FPS?

No, this is by no means an obligation. However, if you are specifically looking for a system to combat viral diseases, we recommend that you choose one with a quality label.  

Can air purifiers used against tobacco smoke also be used for the prevention of respiratory diseases? ​

If the purification device is suitable for cigarette smoke, it will also have a positive effect on aerosols. It should be noted that the particles that make up smoke (PM 2.5 or less) are as fine as those in aerosols containing respiratory pathogens.  Therefore, a purifier capable of measuring a CADR of type PM 2.5 or a second-hand smoke (SHS) flow, can also be used to prevent respiratory diseases. It is therefore advisable to read the documentation accompanying the device carefully to verify its performance levels. The use of these purifiers is recommended provided that the CADR (Clean Air Delivery Rate) value or the purified air flow rate mentioned in the documentation is used. It should also be noted that the CADR is only guaranteed if the device has been well maintained.


The Law of 6 November 2022 for the improvement of indoor air quality

Which spaces are targeted by the Law of 6 November 2022?

The law aims to improve indoor air quality in all closed spaces accessible to the public, i.e. all places enclosed by doors or walls and fitted with a ceiling or floor that are not limited to the family sphere or purely to the professional sphere.

In other words, your home and meeting rooms at the office, for example, are not affected by this law.

Where is it best to display the CO2 meter results to the public?

It is recommended that the CO2 meter be installed in a location that is clearly visible to visitors, unless an alternative, publicly accessible, real-time display system is provided.

Is one CO2 meter per venue sufficient?

At least one device per venue is recommended.

If two units installed in the same space in an area frequented or likely to be frequented by the public show very different concentrations, this may be the result of a build-up of stale air in certain areas or a faulty measurement device.