Atmospheric aerosols and properties of aerosol particles

In physics, an aerosol is defined as the dispersion of solids or liquids (the dispersed phase) in a gas (the dispersant). More generally, dispersion is a heterogeneous mixture of at least two substances that are not soluble within each other (in contrast to molecular dispersion). However, the classical scientific terms are colloid and colloidal system. Colloids exist between all gas, solid and liquid combinations with the exception of gas-gas (all gases are mutually miscible) L - liquid, S - solid, G - gaseous  

The eonfusion in using different terms for elassifying atmospheric disperse systems was diseussed by Grimm (1931). The WMO elassification (manual of eodes) of horizontal obscuration into categories of fog, iee fog, steam fog, mist, haze. 

The phrase Bioaerosol is defined as airborne particles, large molecules that are living. .. (Ge-lencser 2004, p. 70) contains two more errors Aerosol is more than a particle and even the largest existing molecule is not living (Chapter 2.2.2.1). 

If we can see less than 1 km through the cloud of water droplets, it is known as fog. If we can see between 1 and 2 km, we call it mist. A fog is a cloud that has come into contact with the earth s surface. Mist is very thin (concerning number density) fog. 

In contrast to hydrometeors, APs are always in the air, but not all types of APs can be observed at any time because of different sources and formation conditions (Table 4.11). The entity of APs is called PM or simply dust. Suspended matter in air was separated by Carl Wilhelm von Ndgeli in 1879 into the three classes a) coarse (visible through human eyes), b) sun-dust (visible through light scattering) and c) non-visible, only through water vapor condensation detectable (cited after Rubner et al. 1907). 

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