Particulates

n. substance that is composed of separate particles

Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. They range in size from less than 10 nanometres to more than 100 micrometres in diameter. The notation PM10 is used to describe particles of 10 micrometres or less and PM2.5 represents particles less than 2.5 micrometres in aerodynamic diameter; other numeric values may also be used. This range of sizes represent scales from a gathering of a few molecules to the size where the particles no longer can be carried by the gas. Sources of particulate matter can be anthropogenic or natural.
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Noun
1. a small discrete mass of solid or liquid matter that remains individually dispersed in gas or liquid emissions (usually considered to be an atmospheric pollutant)
(synonym) particulate matter
(hypernym) material, stuff
(hyponym) dust
Adjective
1. composed of distinct particles
(antonym) nonparticulate

Carbon particles formed by partial oxidation and reduction of the hydrocarbon fuel. Also included are trace quantities of metal oxides and nitrides, originating from engine wear, component degradation, and inorganic fuel additives. In the transportation sector, particulates are emitted mainly from diesel engines. (DOE6)

1. Fine liquid or solid particles such as dust, smoke, mist, fumes, or smog, found in air or emissions. 2. Very small solids suspended in water; they can vary in size, shape, density and electrical charge and can be gathered together by coagulation and flocculation.