Germans embrace fresh air to ward off coronavirus

Ventilating rooms has been added to the German government’s formula for tackling coronavirus, in refreshing news for the country’s air hygiene experts who have been calling for it to become official for months.

The custom is something of a national obsession, with many Germans habitually opening windows twice a day, even in winter. Often the requirement is included as a legally binding clause in rental agreements, mainly to protect against mould and bad smells.

But while some people may dismiss the method as primitive, “it may be one of the cheapest and most effective ways” of containing the spread of the virus, Angela Merkel insisted on Tuesday.

The German chancellor explained that the government’s guidelines to tackle the virus, encapsulated in the acronym AHA, which stands for distancing, hygiene and face coverings, will be extended to become AHACL. The “C” stands for the government’s coronavirus warning app, and “L” for Lüften or airing a room.

“Regular impact ventilation in all private and public rooms can considerably reduce the danger of infection,” the government’s recommendation explains.

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Impact ventilation, or Stosslüften, which needs explanation for most people unfamiliar with Germany except for experts in air hygiene, involves widely opening a window in the morning and evening for at least five minutes to allow the air to circulate. Even more efficient is Querlüften, or cross ventilation, whereby all the windows in a house or apartment are opened letting stale air flow out and fresh air come in.

In Germany, windows are designed with sophisticated hinge technology that allows them to be opened in various directions to enable varying degrees of Lüften.

Since it has become known that 90% of Covid-19 patients pick up the virus indoors, the practice has come into its own. With winter on the doorstep, it will become even more important, experts insist.

The country’s leading coronavirus expert, Christian Drosten, who is head virologist at the Charité hospital in Berlin, has already dedicated an edition of his hit pandemic podcast to the importance of Luftverdünnung and Luftbewegung – air rarefaction and movement – in which he extols the praises for frequent airing, while the weekly Die Zeit has published a 10-page feature on ventilation, including the science behind it and, especially how to do it in winter.

Even without coronavirus, Martin Kriegel, an engineer and air current analyst at the Technical University in Berlin, told Die Zeit, “there is clear evidence that air quality in offices correlates with the number of days workers are off sick”.

Schools, which have increasingly been viewed as a testing ground for how society can learn to live with the disease, have long since adopted the practice. A recent gathering of the ministers of education for Germany’s 16 states was dedicated to how to air a classroom. Five experts, from fluid mechanics to indoor air hygienists and aerodynamicists, reinforced the importance of airing a room every 15 to 20 minutes, for five minutes in spring and autumn, and three minutes in winter.

But although the custom is well-established in Germany, it is also a frequent cause of tension, which some fear is only likely to increase this winter the more people practise it.

The typical grumpy German response of someone objecting to an open window, is erfroren sind schon viele, erstunken ist noch keiner – many people have frozen to death, but no one has ever died from a bad smell.

Helen, a 34-year-old primary school teacher from Cologne, who did not want to give her full name, said: “A typical scenario in Germany is someone opening the window in an office or on a train, say, then the next person comes in and complains it’s draughty – that’s another German obsession – and insists on closing it. That’s also why Germans often wear scarves.”

She has been following the recommendations and airing her classroom every 20 minutes, she said. “I do enjoy regularly airing, whether in the classroom or at home, and now because of the coronavirus it seems more important than ever. Though I am concerned how I will manage with the kids in winter when it’s really cold.”