CO2 levels as an indicator of ventilation performance in mechanical ventilated buildings

The current COVID-19 pandemic has attracted considerable attention from the general public and researchers. To increase this resilience toward global pandemics, we urgently need a deeper understanding of effective protection strategies. During the COVID-19 pandemic, more evidence confirms that airborne transmission plays an essential role in spreading pathogens. The ventilation systems play an important role in removing pathogens from indoor air. The current paper focuses on examining the air ventilation performance of the existing building stock before Covid 19 pandemic. The study was carried out in mechanical ventilated 440 spaces in four different building types by comparing the obtained individual CO2 concentration data with the maximum concentration values given by official regulations, recommendations and guides. The data was obtained from the property maintenance program for one month at 5-15 minutes intervals. The risk spaces were studied in detail, and the risk analysis was conducted by applying the Wells-Riley approach. The research proposes recommendations for utilising air ventilation systems in different applied cases.