COVID-19 has put the burden of clean air on hospitals and schools around the globe, as well as other commercial establishments such as dental surgeries, gyms, offices etc. In any indoor setting, fresh air is key to diluting the air and high CO2 levels is a good indicator for when more ventilation is required.
Fresh air should always be available either through open windows/doors or through your mechanical HVAC system (check this uses fresh air rather than recirculated air). When CO2 levels are high, open the windows or turn up the HVAC system - this will dilute smaller airborne particles that can hover in the air for several hours.
"A ventilation policy is NOT the same thing as an Indoor Air Quality Strategy"
Indoor Air Quality
Although CO2 is an important part of Indoor Air Quality (IAQ), it is NOT the primary consideration. If you are not also monitoring particulates or chemicals in the air, how will you know if you are providing a healthy environment for your employees?
An HVAC system will provide fresh air for ventilation, but will most likely not purify the air without an expensive upgrade.
Windows or an HVAC system will help you meet your ventilation targets but an air purifier helps you meet your IAQ targets. Choose a good commercial purifier suitable for your room size and the speed you are likely to r