The transfer of dust from Africa to the central Mediterranean and our country is characterized by episodes that last from two to four days. Central Algeria is the most frequent source of the dust that affects us, as well as the mountains of northern Chad. The largest dust production in the world is in the Bodélé Depression in Chad and the Sahara.
During the spring season, barometric lows - cyclones moving from Morocco to Libya and Egypt along the northern coastline of Africa, transport dust to the eastern Mediterranean. A typical sandstorm that has a range of 200 kilometers carries 20 to 30 million tons of dust and rarely up to 100.
Globally, 1.270 million tons of dust are released into the atmosphere annually, ten times more than when measurements began in 1947. Overall from across the Sahara, dust volumes have increased 4 to 6 times since the 1960s. The consequences of this rapid increase are certain to cause significant changes in climate and directly affect human health. The effect of this transfer and deposition of dust and sand reaches great distances, thousands of miles away from the desert.
Dust can particularly affect the most vulnerable groups of the population with chronic respiratory problems, but mud rain is known to bother many more, especially drivers due to their dusty cars. In our area, however, dust and mud rains date back to the era of horse-drawn chariots, thousands of years ago.
The first written record of mud rain is by Homer, in verses (Rhapsody P) 458- 460 of the Iliad in which he describes the "bloody drops", sent by Zeus to avenge the killing of Sarpedon's son by Patroclus in the Trojan War.

The dust makes its journey to the upper layers of the atmosphere – between a height of 1,500 meters to just over 8,000 meters. The dust will then either pick up water vapor and merge with it as mud rain, or it will end up suspended on the ground. However, the depositing of dust affects the environment, changing the levels of carbon dioxide in the atmosphere. Dust falling into the oceans multiplies plankton which absorb carbon dioxide and lower the sea surface temperature, resulting in fewer clouds and less precipitation. This is a vicious circle that worsens the dust problem. The mere suspension of dust in the atmosphere on the one hand reflects heat to space, but on the other hand it also covers the earth, preventing it from radiating its own heat.
According to Oxford University Geography Professor Andrew Goudie, “Dust in the atmosphere and its rapid increase especially in recent years is due to the use of cars in the desert and started at the end of the Second World War but continues to increase until the present day. We also have tourists who come to drive around the desert in their various SUVs." "I'm serious," Mr. Goudie clarifies. “If you take a look at the deserts from satellites, you will see that their entire surface is etched with wheel tracks. If it were up to me, I would only allow these vehicles to be driven on roads."
"The world is getting increasingly dustier. Along with urbanization caused by earth’s growing population, the destruction of forests, environmental disruption caused by the use of 4X4 vehicles in the desert is a key element. The desert surface has been stable for thousands of years because it usually has a thin crust of either lichens, algae or small pebbles that protects the fine sand below. But as soon as this thin crust is broken by the wheel tracks, the fine sand is immediately released into the air and creates sandstorms. The phenomenon is particularly visible near cities, such as Nouakchott, the capital of Mauritania, around which there are wheel tracks leading in all directions into the desert.”"Dust", continues Professor Goudie, "is one of the least understood factors that affect the earth's atmosphere, but it is more important than we imagined for the climate crisis".
On the other hand, the German professor Tegen of the German research group that studies the dispersion of dust at a planetary level, calculates that only 10% of dust movement can be directly attributed to human activities, with the largest percentage depending on air humidity, wind strength and other meteorological parameters. However, with the data we have so far, it is not possible to fully confirm or to completely dispute the case of Mr. Goudie's work. What is your opinion?
Tassos Arniakos