“Clouds in the atmosphere contain condensed water mixed with fine particles. The conditions of supersaturation in the atmosphere show that the formation of water droplets happens with heterogeneous nucleation, which requires aerosol particles. The aerosol particles that nucleate liquid cloud droplets are known as cloud condensation nuclei (CCN), while particles that stimulate the formation of ice crystals are named ice nuclei (IN). A mechanism of change between water vapor and aerosol particles occurs to produce condensed water state from gas state. Hygroscopic cloud seeding uses particles such as salt crystals, which can adsorb water vapor in warm clouds. Hence, the progression of condensation is directly dependent of the hydrophilic or hydrophobic characters of the particles.
Nanoparticles play an important role in the water droplet formation.”