果冻传媒

Management Summary

This PPP combined expertise from virology, aerodynamics, droplet physics, transport in porous media and crowd control towards the safe and full reopening of (semi-) indoor sports venues during the COVID-19 pandemic. The consortium consisted of Eindhoven University of Technology, Leiden University and Medical Center, Utrecht University, Johannes Kepler University in Linz (Austria), Johan Cruijff ArenA, Bovano Basketball (Maaspoort), PlasmaMade.

Infection risks exist for athletes and spectators in crowded football stadiums, indoor sports halls and fitness centers. Top sports 鈥渓ead by example鈥� and stimulate mass participation in recreational sports. This way, they help reduce the burden of disease and on healthcare services by promoting a healthy lifestyle. They also generate substantial economic revenue. Decreased fitness activity, empty or near-empty stadiums and sport halls, lower sports goods sales, diminished social revenue in health and well-being and cancelling 鈥渉allmark鈥� events were having detrimental consequences due to measures related to the COVID-19 pandemic.

This project aimed to develop fundamental knowledge towards safe and full reopening of sport venues in five work packages: Virus dose and duration in aerosols; Individual droplet and aerosol emission; Aerosol concentrations inside sports venues; Crowd control; Overall risk assessment methodology, guidelines, communication, dissemination.

In WP1 an extensive literature study was undertaken, led by researchers from LUMC and involving 16 experts from various disciplines. The main aim of this study was to gather novel insights in the routes of transmission of SARS-CoV-2 from both scientific literature as well as broadly available data. These insights can be used as a and air cleaning were carefully controlled and varied. Detailed high-resolution measurements were made of aerosol particle concentrations in this room. The study showed that a powerful air cleaner or mechanical ventilation can improve the indoor air quality by means of aerosol particle removal in a reasonable and acceptable time. When these two systems are used in combination, it requires only about 15 minutes to remove most (80%) of the aerosol particles of all size fractions in the room used for this study.
WP3 consisted of in-situ measurements of aerosol concentrations in a large (semi-) enclosure stadium (Johan Cruijff ArenA). Due to restrictions during the pandemic it was not possible to perform extensive measurements in a stadium full of spectators, hence, a measurement protocol including the use of artificial aerosol generators and the use of portable aerosol concentration measurement devices needed to be developed. Subsequently, a measurement team of 8-10 persons performed intensive measurements in the stadium for several weeks. This generated a massive amount of data that have been processed in the past years, including aerosol concentrations, air temperature, relative humidity and CO2 and TVOC concentrations. The effect of air cleaning on the aerosol concentrations in the stadium was assessed by employing systems by the Dutch company PlasmaMade. In addition to the in-situ measurements, detailed computer simulations (computational fluid dynamics; CFD) were performed that reached a record number of 6 billion cells. A successful press conference was organised in the Johan Cruijff ArenA in December 2020, and a scientific publication is pending completion.
In WP4, an efficient modelling framework for the investigation of aerosol-based COVID transmission among moving pedestrians was developed. In essence, further developed recurrence CFD (rCFD) simulations (accounting for aerosol transport by airflow) were combined with pedestrian crowd simulations. Despite their three-dimensional nature, these comprehensive simulations run in real-time, thus enabling the consideration of a large number of different spreader-to-victim transmission scenarios.
After validation of this novel version of rCFD, its applicability was showcased using a generic configuration of pedestrians lining-up in front of a cubic building (e.g. a ticket counter). It was shown that the ambient airflow significantly influences transmission probability. More specifically, it was shown that the amount of infected aerosol transmission increased by a factor of three, if the pedestrians queue up in the sheltered wake of the building instead of the wind-exposed side.
Finally, in WP5, a COVID-19 risk assessment methodology (RAM) has been developed based on the results from WP1-4 and has the objective that visiting sports venues would not lead to an unacceptable risk on SARS-CoV-2 infection. The RAM takes into account the three potential transmission routes, and considers human behaviour and building characteristics. It should be demonstrated in the risk model (ISO-31000) that ventilation and/or air cleaning measures with sufficiently high intensity enable visiting the sports venue without unacceptably high infection risk.