Now that society's sights are set on increasingly relaxing the rules, meeting with others much more often and doing things together once again, the importance of measures and interventions that ensure this can be done safely is also increasing. That is why VITO and eu.reca vzw joined forces to host a webinar devoted entirely to the topic of indoor air purification, or the use of devices that actively purify the air by trapping and/or inactivating virus particles.  

The importance of ventilation

By now we should know that even if they are without symptoms, an infected person spreads virus particles while breathing, speaking, singing or coughing. While a decent mouth mask is able to capture large droplets perfectly adequately, the very tiny particles, called aerosols, can still persist and linger in a room for up to 3 hours. Even the WHO is also now emphasising the fact that the virus spreads through the air. Keeping our distance, wearing mouth masks and making sure that we thoroughly ventilate living rooms, offices or restaurants could well be more important than constantly disinfecting door handles or shopping carts.

"Coronavirus floats in the air for hours and travels much further than one-and-a-half metres. It also accumulates indoors, which is why we need to ventilate a whole lot more," emphasised Marianne Stranger, an expert in indoor air quality at VITO. "Ventilation is a preventative measure that everyone should use. Especially if you are with several people in a room, regularly opening a window as wide as you can is a necessity. The concentration of carbon dioxide (CO2) is easy to monitor, so knowing when you need to aerate a particular room is easy to determine." 

Air purification

But what about spaces that you can't adequately ventilate, for example because the windows cannot be fully opened? "Devices are available that actively purify the air. That, in itself, is not new: air purification has already been in use for a long time in operating theatres at hospitals and in other places too. However, if you are going to deploy such devices widely, you want to be sure that they can be used safely by everyone and, of course, that they have been proven effective in the fight against COVID-19," says Jade Verrept, coordinator of the eu.reca network. "In a pandemic like this, one thing you definitely don't want to do is instil a false sense of security in people." 

This is also the reason why VITO and eu.reca invited a series of international experts to give their views on the airborne character of COVID-19, on existing air purification techniques, and on when and where they are useful and where additional research is necessary. 

Jade Verrept (eu.reca) and Marriane Stranger (VITO)

"Though it's a fact that installing an air purification device can be very useful in some circumstances, the introduction of air purification devices must be done with the necessary caution. Not only the effectiveness and safety of the device in question are relevant, but also the flow rate at which the air is purified, the place where you put the device itself and the way you maintain it," explains Marianne Stranger.  

How to obtain healthy indoor air?

It is therefore a good thing that air purification is also being included as a preventative measure. The recent ministerial decree and the Task Force Air Purification of the Coronavirus Commission have already created a framework for this. "That's right, Belgium is opting to respond to this crisis by pursuing new developments. But that is just a start. Consumers need to be informed and guided in their choice. Just like you can find information about fire safety and there is a regulatory framework for it – what type of fire extinguisher to buy, where to hang a smoke detector so that it is effective, when to install a fire ladder or smoke evacuation system – there should be a procedure for healthy indoor air and how best to obtain it," agreed Marianne Stranger and Jade Verrept. 

That is a conclusion that Nico Seymus from Vinçotte can also support. "We support this initiative because we too, as an inspection and certification body, receive a huge number of questions from companies that want to create a safe indoor climate, but are looking for guidance and advice. In April last year, we launched the SafeZone certificate, which allows you to demonstrate that you are following the COVID-19 guidelines, but we also carry out check-ups into the effectiveness of HVAC systems. In order to create a safe indoor climate, many factors must be taken into account and it's a continuous learning curve. For individual companies, this is very difficult, therefore, I hope that the government will involve the TIC (Testing Inspection & Certification) companies to provide the necessary support." 

Whatever the situation, it remains important to consider air purification as one of the preventative steps needed to reduce the risk of COVID-19. The rules of thumb are simple. Tackle the problem at source – avoid places where many people sit inside, wear a mask and get vaccinated, so fewer particles can spread into the air. And other than that, avoid contamination by ventilating all the time and, if necessary, additionally purifying the air. 

You can obtain a comprehensive summary of the webinar via

Webinar supported by Flanders Innovation & Entrepreneurship (VLAIO) by means of the industry 4.0 partnership SIRRIS/AGORIA.