Dust cloud from the Sahara caused extremely high particulate matter pollution
Published: Sunday, Mar 31st 2024, 13:00
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The large amount of Saharan dust over Switzerland has caused exceptionally high levels of particulate matter. Some of the particulate matter values recorded by the measuring stations were "massively above the limit value", as meteorologist Urs Graf from MeteoSwiss told the Keystone-SDA news agency on Sunday.
In some cases, the scale had been "blown up", he said. The daily limit is 50 micrograms per cubic meter of air. On Friday, the average value at the measuring station in Davos GR was 134 micrograms, on Saturday it was 107 micrograms. High values were also measured in Lausanne (81) and Bern (54).
The thick layer of Saharan dust that reached Switzerland on Friday had largely cleared away by Sunday, as Graf said. Some of it was also washed away by precipitation during the night.
According to meteorologists, a dust cloud as thick as the one Switzerland experienced was rare. Saharan dust clouds with a lower dust content, on the other hand, are quite common.
The dust cloud clouded the skies in Switzerland on Friday and Saturday. Swiss meteorologist Roman Brogli said on SRF radio that according to model calculations, there were 180,000 tons of Saharan dust over Switzerland on Saturday alone, an "exceptionally large amount".
The dust was deposited on snow, among other things, and turned it yellowish. According to MeteoSwiss, the dust generally accelerates the melting of snow - at least as long as no significant fresh snow covers the dust layer again.
The Sahara Desert in northern Africa is the largest source of mineral dust, with 60 million to 200 million tons of dust being released every year. Large particles quickly fall to the ground again, while the smallest particles can be blown thousands of kilometers to Europe.
©Keystone/SDA
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