The pandemic has accelerated awareness of the influence of indoor air quality on health. COVID-19, like other respiratory diseases, is spread mainly by aerosols, a kind of tiny droplets, released through the nose and mouth as soon as we breathe, cough, speak ... These aerosols can be removed from the air by ventilation and/or air purification.
Ventilation/purification is fundamental to the control of COVID-19
Ventilation is the continuous addition of fresh outside air into the room and the removal of polluted inside air. Air purification technology has been around for a long time but has only recently been used on a larger scale to remove infectious aerosols from indoor air.
A good ventilation rate can be determined from the CO2 concentration in the air. Outside air contains about 400 ppm of CO2 (which means that CO2 represents 0.04% of the volume of air considered). Indoors, when people in a room exhale air, they add CO2 to it. If the indoor CO2 concentration level remains below 900 ppm, ventilation is considered very good and there is at least 40 m³/h of fresh outdoor air per person.
A completely innovative calculation method
The experts of the FPS Public Health have developed a calculation method to evaluate and quantify indoor air quality. As part of the pilot project "Here, only the film will take your breath away!", this tool is being tested in a "real world" test by the cinema operators, the initiative's partners.
The project, based on self-monitoring, allows operators to:
- map ventilation and/or air purification flows
- comply with a certain maximum CO2 concentration
- combine these two approaches.
The tool determines the room's maximum capacity (maximum number of people allowed in the room). It also calculates the CO2 concentration that will be reached if the systems are working properly.
The higher the ventilation or air purification flows, the greater the number of people allowed in the room.
Operators perform these analyses for each room and submit the data to the FPS. This data can be used in case of inspection by the authorities.
The capacity is determined not only by the number of seats in a room but also by the amount of fresh or purified air that enters it. This dynamic makes this approach innovative and unique.
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