Suspended particulate matter or SPM are fine solids or liquids particles that may be dispersed through the air because of activities like combustion processes, industrial activities or natural sources (like volcanic eruptions.)

Two sources which may cause air pollution due to SPM are:

a) Automobiles: Automobiles run on petrol and diesel burning of which produces SPM which get suspended in the air.

b) Industrial activities: Activities like mining, construction, building demolition also release SPM in the air. These activities release a large amount of dust particles in the air which get picked up by the wind and get suspended in the air around.