Following the COVID-19 pandemic, considerable attention is now being paid to building ventilation as a key measure to control the transmission of respiratory diseases and promote well-being among the occupants. This is especially critical in high turnover environments of public buildings, such as waiting rooms, where ensuring adequate Indoor Air Quality (IAQ) through mechanical ventilation (MV) systems is essential, as the daily constant exchange of individuals can facilitate cross-infections. This work presents a comprehensive investigation of long-term air monitoring conducted in a waiting room in Milan, Italy, equipped with a conventional MV system featuring schedule-based activation. Environmental parameters such as air temperature, relative humidity, CO2, and other common indoor pollutants were recorded, along with the turnover of individuals. Analyses showed that the installed MV system can provide suitable IAQ levels and limited infection risk during the considered periods. Additionally, a CO2-based control strategy was proposed to balance IAQ and energy consumption in these kinds of environments, revealing 50% potential energy savings compared to the schedule-based control without compromising IAQ levels.