ABSTRACT
Following a COVID-19 outbreak in an elderly-care home in Belgium by winter/2020, an assessment of the ventilation conditions at said care home was conducted in summer/2021. Four common-rooms were selected as the most-likely involved in the outbreak and assessed via (artificially-injected) CO2-decay test for average air change rates (ACHs) measurement. Two of the rooms were also assessed via passive tracer gas test for long-term ACHs measurement, using decane-D22 as tracer. The average ACHs measured (via both methods) ranged from 1, 8 to 3, 6 h-1 in summertime, being thus probably higher than the ACHs during the outbreak. Nevertheless, none of the ACHs measured comply with the latest recommendations for COVID-19 prevention. Ventilation grilles and decentralized ventilation systems in common areas could enhance the building's ventilation, but thoughtful installation is essential;experience shows that thermal discomfort often leads to closing ventilation grilles even during a pandemic, resulting in significantly diminished fresh-air supply. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.