Ventilation performance in cultural centres in Flanders

Ventilation impacts the quality of the indoor environment. Indoor air quality (IAQ) contributes to the overall personal exposure of occupants of a building to certain pollutants and is therefore an important environmental determinant of health. Research shows that European citizens spend on average 90% of their time indoors. The Flemish government, and more specifically the Flemish Department of Environment & Spatial Development, has been conducting research on IAQ in homes and schools to inform and develop policy since 2007. In 2019, the Environment and Health research team at the Flemish Department of Environment & Spatial Development, together with VITO (Flemish Institute for Technological Research) developed a sensor box with innovative and high-quality sensor technology — indoor@box, which allows continuous, real-time measurement of several pollutants and parameters. This makes it possible to communicate results real time, to collect a lot of data over longer periods and to make links with other data (e.g. weather, questionnaires, occupancy rates). 
With these indoor@boxes, the Flemish Department of Environment & Spatial Development has been conducting various measurement campaigns in (semi-)public buildings where many people gather or stay, such as schools, sports centres, residential care centres and cultural centres, since 2020. The analysis mainly focuses on CO₂ measurements and ventilation performance. The reports aim at providing concrete advice that considers the specific situation of the building, so that the ventilation improves. In addition, the research gives advice to the policy, which uses existing health guidelines that were important during the COVID-19 pandemic (e.g. in terms of CO₂ values in (semi)public buildings). The research allows to check whether those guidelines are feasible and effective for the different sectors. Ventilation performance can be assessed thanks to a thorough technical screening of the ventilation systems in place.  
This paper elaborates on the campaign in ten different cultural centres in Flanders and Brussels, which varied in size, building type, ventilation system and audience capacity (2022). Overall, the cultural centres' ventilation systems are unable to meet the CO2 guidelines at higher occupancies. The thorough technical screening uncovered that having a ventilation system with sufficient flow rate pulse, in relation to the maximum capacity of the event space does not always guarantee desirable CO2 values. Additional parameters have an influence, e.g. settings of the ventilation system, activity degree and flow rate per person (m³/hr/person), composition of the audience, maintenance and management of the system…The combination of CO2 measurements and technical screenings complement each other well, showing where improvements are needed, and how the ventilation performance can be improved. In the future, the findings from this research could be summarised and incorporated into technical guidelines.