Particles are classified according to the so-called fractions (size of fragments).
In the classification of particles of the fractions to be taken into account that non-spherical particles are frequently (such as asbestos fibers).
Therefore, theoretical models must be used.
The most widespread is the definition of aerodynamic diameter . This is a theoretical size to not be able to assign a spherical particle size.
In the classification of particles of the fractions to be taken into account that non-spherical particles are frequently (such as asbestos fibers).
Therefore, theoretical models must be used.
The most widespread is the definition of aerodynamic diameter . This is a theoretical size to not be able to assign a spherical particle size.
A particle having an aerodynamic diameter of 10 microns is moved, for example, in a gas such as a sphere with the normalized density of 1 g / cm 3 in the same settling velocity in still air or with a laminar diameter of 10 microns , that is the same size.
Diameter of particles extending from less than 0.01 microns to greater than 10 microns. These dimensions correspond to the size of several molecules up to a size wherein the particles are no longer carried by a gas.
| Group | magnitude | |
|---|---|---|
| PM 10 (common thoracic fraction) | <= | 10.0 ? |
| PM 2.5 (respirable fraction) | <= | 2.5 ? |
| PM 1 | <= | 1.0 ? |
| ultrafine (UFP or UP) | <= | 0.1 ? |
Click the image to the different circles to see the different fractions.
