Using AirVisual app I notice there is a huge patch of pollution in Africa. I cannot imagine there is a big economic activity to support that huge pollution across almost the whole continent. What could be the cause of those pollution in Africa.
What you can see in your image is mostly dust from the shara desert https://earth.nullschool.net/#current/particulates/surface/level/overlay=pm10/orthographic=13.33,5.70,766
You will be able to see other types of particles like smoke from combustion like cars-industry-forrest fires,the picture show particles that is 10 microns in size.
On the linked page you can find details of other types of chemical and particulate emissions too like SO2 and CO2 it is a good source for information about the atmosphere.