Aerosols
Q&A
The minerals in the air.
Atmospheric dust refers to the mixture of particles in the atmosphere, which originate from the world´s deserts.
They vary in size, composition, and origin, and can remain airborne for days to weeks, crossing entire ocean basins before settling back to Earth through rain or gravity. Dust is not a curiosity: it is one of the dominant aerosol types by mass, and its effects on climate, health, and ecosystems are the subject of active scientific research.
Where does the dust come from?
Most of it starts in a handful of places.
The majority of mineral dust in the atmosphere originates from the Sahara and the broader Northern Hemisphere Dust Belt. Strong surface winds erode dry, unvegetated soils, lofting particles into the boundary layer and, under the right conditions, into the free troposphere. From there, large-scale atmospheric circulation carries them across the Atlantic to the Caribbean and Amazon basin, or over Europe and Asia.
What about biological aerosols ?
Not all aerosols are mineral dust. Take pollen.
Pollen grains are released by plants during their reproductive cycle and can reach the atmosphere in large quantities. Their role is different from that of mineral dust. During a thunderstorm pollen can fragment into sub-micron particles that penetrate deeper into the respiratory system.