AHAL

In a previous blog, I made my readers familiar with the triad AHA, i.e., distance, handwashing, and wearing a simple mask, a German rule in times of Corona. Now, this triad has been enlarged to a foursome by adding the letter L to it, standing for the German word lüften (airing).

We all had our meetings and shared meals at outdoor restaurants during the warm, sometimes hot, summer. Even in these October days, I see people in Freiburg dressed in pullovers, coats, and ski jackets sitting on sidewalks outside restaurants and cafés being served. They try to catch the last rays of the sun that are no longer warm.

When we have to stay indoors in the coming cold season, the magic word is lüften to make those nasty Corona-contaminated aerosols "gone with the wind."

The tilted window in my kitchen.
Note that the window is like a door that reaches down to the floor.

In Germany, lüften seems to be an easy job. We tilt the kitchen window and briefly tear it open in the bathroom.

When the British "Guardian" writes, "Aeration is something of a national obsession, Germans open their windows twice a day, even in winter!" the world apparently marvels at our domestic ventilation measures. 

Here is an enthusiastic video about German windows:

 

 But richtig lüften is a complicated procedure because just opening or tilting a window is not sufficient. Get familiar with Stoßlüften (push ventilation) and Querlüften (cross ventilation), as only these techniques allow a full exchange of "used" air with fresh air.

My kitchen window is wide open.

During Stoßlüften, you open all the windows in a room "wide" for a short time, allowing for a full exchange of air but causing heat to escape as a side effect.

Querlüften is recommended for improved air exchange. It is more efficient to open windows at opposite ends of your house or apartment, allowing for Durchzug (draught).

Here is where the trouble starts. Germans abhor draughts. Whenever you sit in a ventilated room, e.g., on a plane, the outcry, "Hier ziehts!*" is frequent.

*Help! I feel a draught.

During the dinner at my class reunion, I sat at the end of a table near a window that I liked to keep ajar. Soon, the classmate sitting opposite whined, "Es zieht," and the window was closed. 

This afternoon in my apartment, I am in the green range

After a while, I demonstrated with my pocket CO₂ meter that we had reached a concentration of more than 1400 ppm inside the room instead of the usual 450 ppm in the environment, and the window was opened again. 

N.B.: This meter does not test the SARS-CoV-2 concentration in aerosols, but clearly shows whether the air has become stale with CO₂, and lüften is called for.

The same is true at my Kieser Training. With most windows open, I now support draughts rather than accept billowing aerosol clouds. What will happen when it is freezing cold outside? Can we hope for a mild winter as in recent years?

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