Abstract
The scope of this study is to illustrate the effectiveness of ventilation and air purification systems in reducing indoor pollutants concentrations in densely seated classrooms. Real-time measurements of particulate mass (PM), particle numbers (PN), and CO2 concentrations were conducted in occupied classrooms. In addition, a series of tests employing an aerosol-generating system were carried in an empty classroom in order to evaluate air cleaner removal efficiency in the existence of indoor pollution source (i.e., NaCl). The results of this study show a significant contribution of the ventilation systems equipped with efficient filters in maintaining the indoor air quality in classrooms. In the first scenario, the mechanical ventilation system reduced ambient PM and PN by more than 80%. The indoor-to-outdoor concentration ratios (I/O) were relatively low (0.1 or less) in most classrooms due to the presence of in-line air filters in the ventilation systems, which did not allow the air cleaner to show considerable reductions in indoor PM and PN. The results in the empty classroom showed the efficient use of HEPA air cleaner since it significantly increased the particles decay rates. The decay rate value increased on average from 4-4.7 hr-1 in the natural condition to 6.5-6.7 hr-1 with the use of cleaner at high flow rate, which indicates the effective work of the cleaner unit in reducing indoor air pollution. This work highlighted the importance of classroom air pollution mitigation measures in light of the continuous spread of SARS-CoV-2 variants and the return of classes in-person attendance.
Presenters
Constantinos SioutasProfessor, Civil and Environmental Engineering, University of Southern California, California, United States
Details
Presentation Type
Paper Presentation in a Themed Session
Theme
KEYWORDS
AIR POLLUTION, INDOOR AIR QUALITY, AIR PURIFIERS, PARTICULATE MATTER, VENTILATION
