Self-purification of the atmosphere from aerosol particles has several basic mechanisms. One of them is the gravitational deposition of particles, which depends on the size, mass, density of the particle, and also on the height at which it is located. For particles with a diameter <1 μm, gravitational sedimentation is often not considered, since their lifetime in the atmosphere is relatively high. The most important factors for settling particles are their size and air density. The processes of turbulent mixing play an important role in the self-purification of the atmosphere. Atmospheric convection of different scale acts as a transport agent and transfers particles to areas of precipitation, for example, showers and thunderstorms.
Another mechanism is the coalescence of particles, which, due to turbulent or Brownian diffusion, forms particles of a larger diameter. For them, inertial precipitation becomes significant. The influence on the processes of particle sedimentation can also be exerted by the eclectic field of the Earth.
The cleaning of the atmosphere is also facilitated by the mechanism of aerosol leaching. Atmospheric precipitation purifies the atmosphere of aerosol admixtures in the air. Researchers share cloud and drip aerosol leaching. For both types, the most important factor is the particle size, since drip capture occurs from the rear part of the drop, and the smaller the aerosol particle, the more efficient and faster
there is a seizure. Intra-cloud leaching is important for a fine-dispersed aerosol and is proportional to the total radius of all drops.
Snow and ice precipitation also clears the atmosphere.
Due to diffusion processes, aerosol particles transfer from the area sources (for example, the ocean) to higher layers of the atmosphere. Aerosol pollution from point sources (for example, plants or cities) is transformed and transported with prevailing wind currents (according to the wind rose), forming peculiar trails-geochemical fields, and then gradually dissipating.