5. Glossary

Aerosols; Aerosols

Particles or clusters of particles suspended in the air with a low speed of fall. They may be solid (dust) or liquid (spray), organic (soot) or mineral (eroded rock) in nature, and of varying size (from a few tenths of a nanometer to a hundred micrometers). Aerosols can be classified according to their origin (natural or not), their nature, their mode of formation or their size. In the latter case, they are called PMx (PM stands for Particulate Matter) and represent the quantity of aerosols with an aerodynamic diameter of less than x μm. A distinction is made, for example, between PM10, particles with a diameter of less than 10 μm, and PM2.5, those with a diameter of less than 2.5 μm, whose concentrations are regulated at national and European level.

Atmospheric boundary layer; Couche limite atmosphérique

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