ABSTRACT
In this study, a method was proposed to predict the infection probability distribution rather than the room-averaged value. The infection probability by airborne transmission was predicted based on the CO2 concentration. The infection probability by droplet transmission was predicted based on occupant position information. Applying the proposed method to an actual office confirmed that it could be used for quantitatively predicting the infection probability by integrating the ventilation efficiency and distance between occupants. The infection probability by airborne transmission was relatively high in a zone where the amount of outdoor air supply was relatively small. The infection probability by droplet transmission varied with the position of the occupants. The ability of the proposed method to analyze the relative effectiveness of countermeasures for airborne transmission and droplet transmission was verified in this study. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.
ABSTRACT
To quantitatively evaluate the effect of increasing ventilation using the immediately practicable method on infection risk, the ventilation rate in a classroom was measured by the concentration decay method using CO2. The measured value was then substituted into the Wells-Riley model to evaluate aerosol infection risk in steady and non-steady states. In the classroom, the air change rate per hour (ACH) ranged from 3.1 to 10.2, and the local mean age of air tended to be larger near the outlet. It was also shown that opening the windows increased the ventilation rate the most, resulting in a more evenly distributed local mean age of air. We also showed that the aerosol infection risk in the classroom could be significantly reduced by increasing ventilation, suppressing vocalization, and wearing a mask, compared to some outbreaks of COVID-19. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.