For several days, the southern half of France as well as the overseas territories of Guadeloupe and Martinique have been victims of an unusual phenomenon: the dust of the Sahara. But what exactly is that?
After the fumes of fires in Canada, southern France, but also two overseas territories have been affected by dust came from the Sahara. The latter have strongly damaged air quality in these areas, where Regulatory thresholds for PM10 pollution (fine particles with a diameter less than 10 micrometers), have been exceeded many times. These particles can cause serious health problemslike breathing difficulties Or Merge the state of health of people with lung or heart disease.
Explanation
At this time of year breathes a very powerful wind in West Africa: The African Jet Use of East. On the other hand, the desert of Saharain addition to being very hot, is extremely dry and therefore its surface very easily erodes. This is why when the African jet current arrives at the Sahara, it snatches many particles on the ground and projects them with very high altitudes. The hot air chaasted by the current, is pushed to the westto the Atlantic Ocean where a damp and cold sea air mass is located on the surface.
Before continuing, you should know that thehot air is less dense than cold air. For example, You cannot store so much water vapor in the same volume of hot aironly cold air. Therefore, since theAir above the sea is cold, the air of the Jet-Africain current of is hot,, The latter goes like water on oil, pass over the cold air mass. This phenomenon, coupled with the power of the wind, gives it enough energy to go to the Caribbean, where the air on the surface is less warm, and therefore, the particles go down.
It is for the moment Impossible to know if in the future, climate change could or may not influence this phenomenon.
Consequences
In addition to the health consequences mentioned above, these dust can influence the climate by reflecting or absorbing solar energy. In addition, these dust can fertilize certain floors or oceans or on the contrary saturate them with mineral elements,, making them sterile. Finally, an obvious consequence is obviously Visibility reduction.
