This study presents real-time measurements of particulate matter (PM1, PM2.5, PM10) and carbon dioxide (CO2) concentrations across five university indoor environments with varying occupancy levels and natural ventilation conditions. CO2 concentrations frequently exceeded the 1000 ppm guideline, with peak values reaching 3018 ppm and 2715 ppm in lecture spaces, whereas one workshop environment maintained levels well below limits (mean = 668 ppm). PM concentrations varied widely: PM10 reached 541.5 µg/m3 in a carpeted amphitheater, significantly surpassing the 50 µg/m3 legal daily limit, while a well-ventilated classroom exhibited lower levels despite moderate occupancy (PM10 max = 116.9 µg/m3). Elevated PM values were strongly associated with flooring type and occupant movement, not just activity type. Notably, window ventilation during breaks reduced CO2 concentrations by up to 305 ppm (p < 1 × 10−47) and PM10 by over 20% in rooms with favorable layouts. These findings highlight the importance of ventilation strategy, spatial orientation, and surface materials in shaping indoor air quality. The study emphasizes the need for targeted, non-invasive interventions to reduce pollutant exposure in historic university buildings where mechanical ventilation upgrades are often restricted.
Mustață et al. (Sat,) studied this question.