Safe Work Australia - Monitoring indoor ventilation
Although carbon dioxide (CO2) levels are not a direct measure of possible exposure to the COVID-19 virus, checking levels using a CO2 monitor may help identify poorly ventilated areas. However, CO2 levels will depend on the occupancy density and do not measure the effectiveness of other infection prevention and control measures put in place.
According to the UK Health and Safety Executive, a consistent indoor air concentration of less than 800 parts per million (ppm) CO2 is likely to indicate that a space is well ventilated.
When CO2 concentration measurements average between 800-1500ppm over the occupied period this is an indicator to take action to improve indoor ventilation. An average of 1500ppm CO2 concentration over the occupied period in a space is likely an indicator of poor ventilation. You should particularly take action to improve ventilation where CO2 readings are consistently higher than 1500ppm. However, where there is continuous talking or singing, or high levels of physical activity (such as dancing, playing sport or exercising), a higher level of ventilation may be required to keep CO2 levels below 800ppm, given the higher risks of transmission.
Measurements of CO2 should be taken at different times with different occupancies to get a better indication of how the ventilation system is working under different conditions. There are some situations where CO2 monitors may be less informative, such as areas that rely on air cleaning units, or large, open spaces with high ceilings (e.g. warehouses), or areas with very limited occupation density (e.g. large office areas with one or two occupants). There are many different types of CO2 monitors available and you should consult a ventilation engineer or occupational hygienist about whether CO2 monitoring is required, and which type is best for your circumstances.
You can read more about the Safe Work Australia guidelines here....
