Similar term(s): PM, suspended particulate matter, total suspended particulates, black smoke, inhalable particles, thoracic particles, respirable particles.
Sum of all microscopic solid and liquid particles, of human and natural
origin, that remain suspended in a medium such as air for some time. These
particles vary greatly in size, composition, and origin, and may be harmful.
Particulate matter may be in the form of fly ash, soot, dust, fog, fumes etc.
Based on the size of their aerodynamic diameter particles can be classified as
PM10 (coarse and fine particles), PM2.5 (fine
particles) or PM0.1 (ultrafine particles).