Spit hits the fan: Scientists fill Dutch football ground with aerosol sprays to see how cheering crowds might spread Covid-19
- The fine droplets resembling saliva are sprayed from seats at the Dutch stadium
- Researchers want to find ways to remove the droplets and get fans back inside
- Tests are ongoing at the Johann Cruyff Arena in Amsterdam, Ajax’s home ground
The fine droplets, meant to resemble saliva, are being sprayed from the stands in the Amsterdam ground to find out more about how they behave.
Researchers hope they will be able to develop ways to remove the droplets from the air and get fans back into stadiums and concert halls.
‘There is almost no information in scientific literature about the behaviour of aerosols in this kind of environment’, lead researcher Bert Blocken said.
An aerosol generator sprays fine droplets into the air at the Johann Cruyff Arena in Amsterdam where scientists are testing how Covid-19 might spread among a packed football crowd
A researcher operates some of the equipment which was set up in the stands of the Dutch stadium to prepare for a possible return of fans
The tests are taking place at the Johan Cruyff Arena in Amsterdam, the home of 34-time Dutch champions Ajax.
‘We want to get a fundamental insight in the behaviour of in a stadium filled with football supporters,’ Blocken said.
‘By air cleaning technologies you can drastically reduce concentrations and make stadiums safe in terms of aerosol transmission of the virus,’ he added.
There is growing consensus among scientists that transmission via aerosols plays a part in the spread of the novel coronavirus, although it is unclear to what extent.
The research could provide insight in how to minimise the concentration of aerosols and limit their epidemic risk, said Blocken, a professor in aerodynamics at the Technical University of Eindhoven.
A computer model will extrapolate the data gathered during weeks of testing to show the effects for a full capacity crowd of around 55,000.
Researchers also hope to get permission soon to experiment with a real crowd of 730 football fans, seated close together.
An artificial green aerosol is sprayed by researchers from Eindhoven University of Technology during the experiment in Amsterdam
The green aerosol spray is watched by one of the researchers in the stands of Ajax’s home ground last Thursday
Researchers hope these stands could be full of chanting football fans again if they can remove the infectious particles from the air
Some of the researchers stand among the empty seats in Ajax’s home ground on Monday
The final goal is to get capacity crowds back into stadiums, Blocken said, possibly through the use of large scale Covid-19 testing, face masks and ventilation.
That would be exactly what the Johan Cruyff Arena needs to survive, its director told Reuters.
‘This is a very costly building, and the income is less than half of what is normal, so we are making a loss every month’, said Henk Markerink.
‘We try to keep the ship afloat, but this shouldn’t take too long because in the end this cannot be financed.’
Dutch football was suspended on March 12 as Europe headed into lockdown, and the 2019/20 season was ended in April with no title being awarded.
Some fans were allowed into grounds when the 2020/21 season began, but the experiment was short-lived as spectators were banned again in September.
The Netherlands has seen 573,750 cases and 9,786 deaths in total, according to Johns Hopkins University figures.