Berlin (dpa) - Germany-wide anti-racism protests have triggered a debate about demonstrations in Corona times. Some politicians were concerned about the crowds.

Despite the criticism, the demos of the alliance "Unteilbar" have already set the next major events this weekend. Does this fuel the infection in Germany? 

CONDITION: During demonstrations, there is an increased risk of infection with the corona virus.

EVALUATION: With a face mask and distance, there is no particular danger in demonstrations. However, experts do not recommend loud chants.

FACTS: Demonstrations in the fresh air are initially less dangerous than events in closed rooms, as Christian Kähler from the Institute of Fluid Mechanics and Aerodynamics at the University of the Bundeswehr in Munich explains. "The viral load decreases due to the fresh air." Exhaled air can rise and mix there with the ambient air. The Berlin-based virologist Christian Drosten had also explained - albeit with a view to restaurants and pubs - that a two-meter distance outside was probably not necessary at all. The wind blow the virus away.

But despite the "fresh air" factor, experts believe that there are a few basic rules that must be followed to make demonstrations somewhat corona-proof: mouth guards, distance - and no loud slogans.

For example, when around 15,000 people demonstrated at Alexanderplatz in Berlin, many of them were wearing self-made masks - but minimum distances were often not kept. "A few people will have been infected by then," estimates Kähler.

Wearing masks prevents infectious droplets from flying long distances and also reduces the speed at which air is exhaled and droplets are spread. "But everyday masks are never quite tight." Therefore, the minimum distance must also be maintained if all participants, without exception, wear an everyday mask. Then demonstrations could also be relatively safe.

A view shared by the virologist Jonas Schmidt-Chanasit from the Bernhard Nocht Institute for Tropical Medicine (BNITM) in Hamburg: "The mask is only an additional aid, but should not be an alibi measure." The minimum distance and general hygiene rules are still decisive.

The alliance “Unteilbar”, which is calling for demonstrations in several German cities this Sunday (June 14), wants to take this into account. Demonstrators are expected to line up along a long road to form a “band of solidarity” three meters apart. "We will not endanger each other, we will not have large crowds or crowds as we know from demonstrations," the alliance promises on its website.

The demonstrators should also avoid loud slogans. "The advice is to demonstrate silently," says Schmidt-Chanasit. "If you scream a lot for a long time, a lot of droplets fly and that creates aerosols." These small air particles fly more than a meter and a half and could increase the risk of transmission. However, the role of aerosols in the spread of the virus has not yet been fully clarified.

Aerodynamicist Kähler is also very pragmatic when it comes to quiet demos: "If it's loud and I want to talk to someone, I automatically get closer to them or speak louder." But the louder you talk, the more droplets you produce - the risk of infection increases.

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