A huge dust storm swirling over Europe from the Sahara desert made it hard to breathe in large parts of Spain for a second straight day on Wednesday and gave cleaning crews as far away as Paris, London and Belgrade extra work to remove the film of dirt falling on cars and buildings.
Europeans woke up to eerie skies, from the grimy grey in Madrid to orange hues in the Swiss Alps, caused by the tiny particles that had travelled thousands of kilometres across the Mediterranean Sea.
The European Union's Copernicus Atmosphere Monitoring Service said it was tracking the large mass of dust that has "degraded air quality across large parts of Spain, Portugal and France."
While Spain is bearing the brunt of the storm, dust was flung far beyond, dumping ochre-coloured blobs on cars in a rainy Paris and sifting a fine powder down on a huge swath of the continent.
Experts, including Spain's national weather service, described the event as "extraordinary" for the amount of dust in the air but noted that it had not broken any records.
"This is an intense event, but this type of event typically occurs once or twice a year, normally in February or March, when a low-pressure system over Algeria and Tunisia gathers up dust and carries it north to Europe. Dust can reach the U.K., or even Iceland, as it did last year," Carlos Perez Garcia, a researcher studying atmospheric dust at the Barcelona Supercomputing Center, told The Associated Press.
The area of Spain rated by its national air quality index as "extremely unfavourable" — its worst rating — expanded from the start of the European event on Tuesday to include most of the nation's southern and central regions, including Madrid and other major cities like Seville.
Authorities recommended for people to wear face masks — still in wide use because of the pandemic — and avoid outdoor exercise, especially for those people suffering respiratory diseases. Emergency services for Madrid told the AP that so far there had been no increase in calls for care to people with breathing problems.
Ruben del Campo, spokesperson for Spain's weather service, said that the largest quantities of air-born dust will accumulate on Wednesday afternoon in Spain's southeast and central regions.
"The air will then begin to clear little by little, although some floating dust will reach the Canary Islands (in the Atlantic Ocean) over the weekend," Del Campo said.
To the relief of farmers, the storm front that pulled in the African dust is also forecast to bring more rain over the coming days to Spain's parched fields and descending reservoirs.