Using CO2 as a Ventilation Clue in Classrooms

ABSTRACT

In the era of COVID19, we need to quickly find and fix classrooms that have inadequate ventilation to reduce long-range airborne transmission of diseases. Historically, the limited available data has shown classrooms in the United States to be under ventilated in relation to consensus standard ventilation values that do not consider airborne infectious disease risk. Carbon dioxide (CO2) is a reasonable proxy of emissions from humans. This presentation will discuss the assumptions and uncertainties in using carbon dioxide concentrations as a proxy for ventilation in classrooms. Specifically, the influence of student density and activity level on carbon dioxide concentration will be modeled for a range of student ages and activities. This analysis shows classrooms with high carbon dioxide concentrations (above 2, 000 ppmv) are unlikely to be meeting United States ventilation standards. However, uncertainties mean conclusions cannot be easily made about ventilation rates in classrooms with lower carbon dioxide concentrations. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.