“This phenomenon shows us that air pollution can also have a natural origin. The Atmo Bourgogne Franche-Comté network, the body in charge of monitoring air quality, analyzed the consequences of the passage of the Saharan dust that turned the sky yellow on Saturday.
In fact, it is Sirocco, a southern wind that is usually summer, that blew from Provence towards Alsace, carrying with it the tiny dust that raised a storm in the Sahara. Although the phenomenon is not uncommon, most of the time this dust is transported to very high altitudes, between 1 and 5 km. There, they circulated much closer to the ground and a fine rain pushed these tiny grains of sand to the ground. The devices responsible for measuring air quality have obviously recorded the unusual concentration of these particles, particularly throughout the eastern part of Bourgogne Franche-Comté. So much so that in Besançon and Lons-le-Saunier, the information and recommendation threshold for sensitive people has been exceeded (Atmo’s first alert level).
“In normal times,” explains the organization, “the consequences on our health are still limited. In fact, due to their relatively large diameter (on the order of 1/5 of the diameter of a hair), these particles are retained in the upper ducts of our respiratory system and, therefore, have less facility to enter the body, than it is less the case with less combustion dust (road traffic, biomass heating). “
A possible discomfort for sensitive people
However, the high concentration of these particles may have caused some respiratory discomfort in sensitive people, infants, pregnant women, smokers, the elderly, people suffering from respiratory diseases … Atmo however points out that the duration was very short since the episode was almost completed the next day, the rains having allowed the atmosphere to “leach” these sand particles.