Visibility across vast swaths of northern and central Africa and the Arabian Peninsula has been severely reduced since Thursday as a large-scale disturbance has resulted in huge quantities of Saharan dust being dispersed across the region.
A low pressure system developed over the desert region of Libya and the resulting circulation was responsible for dust being lifted high into the atmosphere. It swept from Egypt and Sudan, across the Arabian Peninsula and on into Kajikistan, Kyrgyzstan and Tajikistan.
There were no reports of flight cancellations, but visibility was severely reduced and many people reported increased respiratory problems.
While much of the dust swept eastwards, some was swept up from Chad and transported southwards and westwards on the northeasterly trade wind known as the Harmatten. Niger, Mali, northern Nigeria, Benin, Ghana, Ivory Coast and Burkina Faso have all been affected.
Chad is the main source of Saharan dust. There are two key locations here. One is the Bodele Depression - the dried up remains of the ancient Lake Megachad.
The other is the Tibesti mountain area in the north of the country. Here, the volcanic mountains are rapidly eroded to dust by the harsh climate.
On a positive note, this mineral dust has great benefits. It will eventually find its way around much of the globe before being deposited in the Caribbean, Asia, South America, Europe and elsewhere.
The dust helps to build soil fertility, being rich in phosphorus, potassium, calcium and iron, depending on its source.
