Eindhoven University of Technology: Studying aerosol dispersal by supporters at Netherlands-Latvia match

A new Fieldlab Events study will take place during the international soccer match between the Netherlands and Latvia on Saturday 27 March. A total of 5,000 spectators will be present in the Johan Cruijff ArenA, while social distancing and wearing a facemask will not be required. Among the scientific studies during this match is an aerosol study led by Eindhoven University of Technology.

The researchers will be looking at tiny saliva droplets produced by shouting and singing supporters during a soccer match in the stadium. More and more scientists are convinced that these tiny droplets, called aerosols, can play an important role in the spread of the coronavirus. On Saturday, research will be conducted into the build-up of aerosol concentrations and the effectiveness of measures to reduce these concentrations, for example by means of ventilation.

TU/e researcher Bert Blocken, who is leading the study, explains. “Many modern stadiums, including the ArenA, are built in a relatively closed structure, with round enclosed corners and a small roof opening. That is best for the comfort of the spectators and for the acoustics. But that also limits the ventilation. We want to investigate how we can better ventilate these kinds of stadiums.” With this new research, the researchers hope to develop a model that can predict the aerosol concentrations in stadiums such as the ArenA.

MAJOR WEATHER INFLUENCES
During the match, the researchers will set up accurate measuring devices in sections 114 and 115, and monitor the temperature, relative humidity, CO2 concentration and aerosol concentration at more than 300 positions. The latter will be measured by continuously counting the number and size of droplets exhaled by soccer fans. In addition, wind speed and direction are being measured at various locations in the stadium. Two different ventilation systems will try to lower the concentrations during the game. One system before halftime, and the other after halftime.


During the match, the researchers will set up accurate measuring devices in sections 114 and 115, and monitor the temperature, relative humidity, CO2 concentration and aerosol concentration at 300 positions. Photo: Bert Blocken
This new test with real supporters follows an earlier study by Bert Blocken in the stadium when the same test was conducted but without supporters. Artificial aerosol generators mimicked the aerosols generated by singing and shouting spectators in that earlier research project. Blocken: “From those tests we learned that, even more than expected, the weather is by far the most important factor in determining how high the aerosol concentrations can rise. Even for a relatively ‘closed’ stadium like the ArenA.”

RECALIBRATION FOR A FULL STADIUM
TU/e is building a large computer model of the ArenA that should be able to predict aerosol concentrations for 55,000 spectators. The measurements of the test on Saturday will serve to calibrate that model. The ultimate goal: to optimize ventilation in the stadium. COVID-19 requires addition interventions, such as ventilation openings at strategic positions and interventions based on the weather forecast and activity in the stadium. Blocken: “Such as ventilation units. But we’re going to investigate that extensively in follow-up studies.”

The research project on aerosol concentrations is taking place under the leadership of TU Eindhoven and in cooperation with Leiden University Medical Center, Utrecht University, Johannes Kepler University in Linz, PlasmaMade, GO2Sure, TeamNL and the test sites Johan Cruijff ArenA, Maaspoort Sports and Events via Heroes Den Bosch and CTO Papendal and CTO The Hague.

The collaborative project is co-financed by a PPP allowance made available by Health~Holland and Top Sector Life Sciences & Health to stimulate public-private partnerships. The study is also being facilitated by Sportinnovator.

For the computer simulations, TU Eindhoven receives help from the High Performance Computing Consortium that, under the leadership of the White House in the United States, supports a number of important COVID-19 projects worldwide with powerful computing infrastructure. This system has been made available by Microsoft and Ansys.