Is a dangerous cloud of “corrosive and acidic” gas hovering over France?

Several Internet users are warning about the presence of a thick cloud of sulfur dioxide over France, without anyone talking about it. However, there is no reason to worry.

“Be careful today, warns Silvano Trotta on X on Monday morning, August 26, France will be plunged into a cloud of sulfur dioxide.” The entrepreneur with 200,000 subscribers, accustomed to spreading false information, had already warned the day before about this cloud. According to him, “Britons have been warned to stay indoors as a cloud of corrosive, acidic gas [provoqué par l’éruption volcanique du 22 août en Islande]which can cause serious health problems, is engulfing the UK”. Alarmist, he wonders if “This gas cloud, like the one from Chernobyl, stops at the borders?”

However, not only is this cloud not dangerous, but it also did not fly over France.

Britons have been warned to stay indoors as a cloud of corrosive and acidic gas, which can cause serious health problems, engulfs the UK in the early hours of this morning.

Weather maps show that a huge cloud of… pic.twitter.com/XXVxOHjcW8

— SILVANO TROTTA OFFICIAL (@silvano_trotta) August 25, 2024

The conspiracy theorist shares a worrying screenshot from the Windy app, which specializes in weather forecasting. It shows a thick cloud of sulfur dioxide (SO2), shown in red, passing over the United Kingdom and France, raising fears of serious health consequences, respiratory problems and even irritations.

But the color is deceptive because, in reality, “The SO2 level is limited and does not represent a health hazard”assures meteorologist Guillaume Séchet on X, especially since SO2 tends to disperse and therefore to be less concentrated. However, “There have to be hundreds of micrograms per cubic meter for several hours for it to be dangerous, especially for babies and people with asthmaexplains to franceinfo Marie Boichu, researcher at the atmospheric optics laboratory of the CNRS and the University of Lille. There, we are at a few micrograms per cubic meter.”

>> Read also: “Is the sulfur cloud linked to the eruption of a volcano in Iceland dangerous for health in France?”

By the way, the map does not represent the level of sulphur dioxide pollution in the air we breathe. It uses the forecasts of the European Centre for Medium-Range Weather Forecasts, which has put its own map online. But when you look at the map, you will see that it shows forecasts of sulphur dioxide concentrations not only at the Earth’s surface, but in a sort of column that starts at the Earth’s surface and rises to the top of the atmosphere. If you only look at the air at the Earth’s surface, the air we breathe, the sulphur dioxide concentrations should actually have been barely higher than usual (always shown in blue – the best air quality – or even in green – air that is always of good quality).

In reality, the forecasts estimated that the sulfur dioxide cloud would pass several kilometers above our heads, without landing in our lungs. There was therefore no reason to worry. Furthermore, contrary to what has been written, the British have not been called to stay at home by the authorities. This false information comes from a false headline in the tabloid Daily Mailwhose rigor and reliability are so doubtful that the newspaper was banned from Wikipedia sources in 2017 as reported by The World.

Besides, all this was just predictions and “Satellite observations available since this eruption do not confirm this prediction”assures Météo France to franceinfo. “Various instruments on board satellites showed that this plume of SO2 had circulated at altitude (between 4 and 7 km altitude) above the British Isles on August 24, and was located off the coast of Norway on August 25, 2024. Very low quantities were also detected at high altitude over northern France and the Benelux on Sunday, August 25.”

“With the observations available at this time, the cloud is still off the coast of Norway, and these satellite instruments do not detect any significant presence of SO2 over France.”continues the public meteorology and climatology service. Indeed, the Support to Aviation Control Service (SACS) of the Belgian Institute for Aeronomy depicted the cloud of sulfur dioxide still next to the Scandinavian country on Monday evening.

Geod’air, the French air quality data platform, shows sulfur dioxide levels in France well below the World Health Organization (WHO) alert threshold of 40 μg/m3 over 24 hours. The same observation can be made on the maps of the European Center for Medium-Range Weather Forecasts following air pollution, and on the Prev’Air platform. In short: the Icelandic eruption has no reason to worry the French.