There are various ways to ventilate an indoor area: by leaving windows open at a tilt, by opening ventilation grilles or gaps, or by using mechanical ventilation systems. Airing out an indoor space is also a form of ventilation. For example, you can open windows and doors across from each other and leave them wide open for 10 to 15 minutes. This is a good idea after cooking, showering or hosting groups of people in a shared indoor space. Airing out the room is a way to let in lots of fresh air at once.

Cooling

When the weather is warm, you may want to use a fan or air conditioner to cool your home. Keep in mind that these devices do not introduce fresh outdoor air, but only move the indoor air around. If you have guests in your home, make sure that your devices are not creating an air flow from one person to another. See also the National Heat Plan.

Portable air purifiers

Air purifiers can reduce any viruses or bacteria present in the air flowing through the device. They achieve this by blocking viruses and bacteria (for example using filters) and/or killing them (for example using UV-C). A portable electrical device that can be placed in a room is called a standalone or portable air purifier. It is not yet known whether this type of air purifier prevents or reduces transmission of the coronavirus SARS-CoV-2 in public places or at home, in the context of sufficient ventilation. It is unlikely that an air purifier situated in a different part of the room will affect transmission of the virus between two people who are less than 1.5 metres apart.  This also applies to transmission via hands and surfaces. 

Air purifiers are not an alternative to ventilation. Ventilating brings in fresh outdoor air to replace stale indoor air. Air purifiers remove particles from indoor air, but do not introduce fresh air from outdoors. To ensure a pleasant and healthy indoor climate, a space should in any case comply with the applicable regulations for ventilation. Also, air purifiers and ventilation cannot be used as suitable replacements for the basic recommendations to prevent the spread of COVID-19: staying home and testing if you have symptoms, distancing, and maintaining good hand hygiene. These measures are aimed at preventing all forms of transmission. They prevent infection with the coronavirus SARS-CoV-2. RIVM does not play any role in approving or advising a particular type of air purifier.

What are RIVM’s recommendations about ventilation?

At a minimum, RIVM recommends compliance with the requirements of the Dutch Buildings Decree (Bouwbesluit) and all current recommendations and guidelines. In addition, RIVM recommends the following: 

• Ventilate indoor spaces 24 hours a day
• Use and maintain the ventilation system according to the user manual
• Check that the ventilation capacity for the space is suitable for how it is being used
• Consult an expert if you are unsure whether ventilation is sufficient 
• Air out indoor spaces regularly (between meetings or classes, during breaks).  

See the LCI website for a full list of recommendations (in Dutch only).