aerosol(s)

Solid or liquid particles suspended in the atmosphere. Strictly speaking, the gas in which these elements are immersed also constitutes the aerosol. The use of the singular or plural form is interchangeable, although the latter is more widespread. Aerosols are of highly variable nature and sizes (microscopic in all cases) and their presence in the air can reduce visibility. Their origin can be natural (volcanic ash, desert dust, pollen clouds...) or anthropogenic (burning of fossil fuels, industrial waste...). In both cases, they play a role in cloud formation processes - acting as condensation nuclei - and influence the climate system, both through that direct - yet complex - relationship with cloud cover, and through the role they play in the Earth's energy balance.