Aerosols & Particulate Matter

Introduction & Definitions

Aerosols are suspensions of solid or liquid particles in a gas (usually air). The particulate portion of an aerosol is referred to as Particluate Matter, or PM. Particulate Matter is a generic term applied to chemically heterogeneous discrete liquid droplets or solid particles. The metric used for describing PM is the micron, or micrometer (1e-6 meters). The PM in an aerosol can range in size from 0.001 to greater than 100 microns in diameter.

Particulates are generally categorized based on size:

Most aerosol particles are polydisperse -- they have a wide range of particle sizes that must be characterized by statistical measures. In some cases, such as with an ink jet printer, it is desirable to have a monodisperse aerosol with particles of equal size.

Aerosol Terminology


Solid-Particle Aerosols:

Liquid-Droplet Aerosols:

Solid/Liquid particle aerosols:


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