Because of the coronapandemic, there is increasing attention for the indoor air in buildings. The Dutch advisory report of 8 July states that the Health Council of the Netherlands and advisory bodies in other European countries recommend the use of CO2 measuring devices to control the air quality in indoor spaces. It is also mentioned that it could be investigated whether the determination of CO2 content in the Dutch setting could be of added value. Is CO2 a good indicator of the risk of contamination in indoor spaces?
What is in the air you breathe out?
Most infections take place in indoor spaces, where people breathe in oxygen and breathe out carbon dioxide, or CO2. The exhaled air consists of 78% nitrogen (N2), 17% oxygen (O2) and around 4% carbon dioxide (CO2). The remaining 1% consists of other components such as gases. Via the exhaled air, the finest droplets of water vapour (aerosols) are released. In the case of an infected person, the aerosols may also contain viruses.
Is there a relationship between aerosols and CO2?
If a healthy person inhales aerosols from an infected person, he may become infected with the coronavirus via the mucous membranes. Provided that it exceeds the minimum dose required for infection. But the more exhaled air (and thus aerosols) are present in the room air, the greater the chance of infection. The concentration of aerosols and CO2 is thus directly related. From the current CO2 concentration, concrete conclusions about the aerosol contamination can be derived. The higher the CO2 value, the greater the aerosol load and the risk of COVID-19 infection.
At which CO2 values should you take action?
The value that a CO2 sensor measures is expressed in ppm (parts per million). CO2 sensors therefore display the proportion of CO2 in the air. It is generally accepted that measured CO2 values of 0 – 800 ppm are safe values. If the CO2 meter indicates a CO2 value of 800 – 1200 ppm, this means that attention is required. An upper limit of 1200 ppm is set for the permissible value for CO2 content in an indoor area. When CO2 values exceed 1200 ppm, it is necessary to take measures.
What can you do if the CO2 value is too high?
When the CO2 meter shows that the value is too high, extra ventilation is recommended. However, in many cases this is not possible based on the available ventilation options. Adjusting a ventilation system is not that simple and buying a new system is very expensive and takes a long time. The use of a (mobile) air cleaner helps to reduce the risk of contamination.
What is the policy of other countries regarding air cleaning?
In Belgium and Germany, mobile air cleaners are used to reduce the risk of infections in rooms with insufficient ventilation possibilities. In Germany, subsidies are available for the investment in mobile air cleaners and the Belgian government has developed a ventilation policy around corona. Our devices, which remove up to 99.95% of the viruses from the air, have been approved in Belgium. Hopefully, the Dutch government will soon adopt the policy of our neighbours before the number of infections rises further as people spend a lot of time indoors again in the autumn.