Inert organic particles come from non-reactive organic material, which is material derived from living organisms and includes carbon-based compounds. Viable organic particles are capable of living, developing, or germinating under favorable conditions; bacteria and fungi are examples of viable organic compounds. Inert inorganic particles are non-reactive materials such as sand, salt, iron, calcium salts, and other mineral-based materials.
In general, organic particles come from carbon-based living matter, like animals or plants, but the particles are not necessarily alive. Inorganic particles come from matter that was never alive, like minerals. A dead skin cell is an inert organic particle, a protozoan is a viable organic particle, and a grain of copper dust is an inert inorganic particle.
Particles are produced from a large variety of sources. Inert particles usually develop when rubbing one item against another, such as the dust produced when you cut through a piece of wood. Humans shed many thousands of inert particles through the continuous sloughing of dead skin and large quantities of viable particles through other natural processes. Electric motors generate inert particles when their wire brushes rub against the rotating components. Plastics, when exposed to ultraviolet light, slowly release inert particles.