(SI) Aerosoli so trdni ali tekoče delci suspendirani v zraku oziroma atmosferi. Delci se v atmosfero emitirajo neposredno iz različnih virov (primarni delci), ali pa nastanejo v atmosferi preko različnih foto-kemijskih pretvorb (sekundarni delci). Prašni delci različnega izvora imajo različno kemijsko sestavo, obliko in različna fizikalna stanja. Aerosoli so vpleteni v številne procese v atmosferi – sodelujejo pri različnih kemijskih in fizikalnih pretvorbah atmosferi, nastanku kislih padavin, vplivajo na prosojnost in električne lastnosti atmosfere. Delci v ozračju pomembno vplivajo na klimo, vreme in tudi na zdravje ljudi.

(EN) Aerosols are solid or liquid particles suspended in the air or atmosphere. Particles are emitted directly into the atmosphere from various sources (primary particles) or are formed in the atmosphere through various photochemical transformations (secondary particles). Dust particles of different origins have different chemical compositions, shapes, and physical states. Aerosols are involved in many processes in the atmosphere - they are involved in various chemical and physical transformations of the atmosphere, in the formation of acid precipitation, and in the transparency and electrical properties of the atmosphere. Particulate matter in the atmosphere has a significant impact on climate, weather, and human health.