PM 10 are particles suspended in the air with a diameter of less than 10 micrometers, hence the name particulate matter 10, abbreviated as PM 10.
Of natural origin (e.g. erosion, volcanism) or anthropic origin (smoke, wear, etc.), these particles remain in the atmosphere for a generally long time. The biggest (over 2.5 micrometers) fall back quite quickly, while the finest can remain suspended for several days and cover thousands of kilometres.
Given that the finer the particle the more dangerous it is to health, PM 10 are subdivided into categories of smaller particles:
- PM 2.5 (fine particles with a diameter less than 2.5 microns);
- PM 1 (very fine particles less than 1 micron);
- PM 0.1 (ultrafine particles less than 0.1 micron) or nanoparticles.
Public health policies and regulations are increasingly addressing these particles, as they are discovered to be toxic (e.g. asbestos, polycyclic aromatic hydrocarbons) and as measurement methods improve.
Some activities produce a large amount of dust. The finer the dust, the more dangerous it is to the health of exposed persons. © Lamiot, Wikimedia CC by 3.0