Topic summary
Fine particles
Extracted from the Wikipedia article Particulate matter.
Categories of atmospheric particles include inhalable coarse particles, designated PM10, which are particles of coarse granularity, with a particle diameter of 10 micrometers (μm) or less; fine particles, designated PM2.5, with a diameter of 2.5 μm or less; ultrafine particles, PM.10 with a diameter of 100 nanometers (nm) or less; and soot (fine or ultrafine particles primarily made up of carbon).