Aerosol
A colloidal system in which solid or liquid particles are dispersed in a gas.
Unit
nm
In depth
Aerosol particles remain suspended because their small size makes gravitational settling slower than air currents. They dominate atmospheric optics and chemistry, providing surfaces for reactions, seeding cloud droplets, and, in the case of fine particulates, penetrating deep into the lungs.
Examples in the real world
Fog and mist as liquid aerosols; smoke and volcanic ash as solid ones; asthma inhalers delivering medication.