The following are definitions for airborne various materials: dust, fumes, smoke, aerosols, mists, gases, and vapors.
- Dust – solid particles produced by applying significant mechanical force to separate them from an object, such as wooden dust from drilling or sawing or minuscule pieces of metal from hammering or friction.
- Fumes – solid airborne particles that are generated from the condensation process. For example, fumes are released into the air during soldering. Some dangerous fumes can be caused by heating lead-containing paint.
- Smoke – an aerosol that is generated as a part of the combustion process, often consists of carbon. It includes byproducts that are released into the air from burning fuel or smoking.
- Aerosols – small particles of solid or liquid material that are suspended in the air. They are separated by their source, which can be human-made, such as air pollutants, or environmental, such as fog.
- Mists – thinly spread floating liquid droplets that are generated by condensation. For example, mists occur when moist air is being cooled; however, a mist can be caused by spraying paint.
- Gases – substances that are in their gaseous state, without volume or shape. They include oxygen, carbon dioxide, helium, and other chemical elements and compounds.
- Vapors – are gases that can be condensed into liquid form under normal circumstances. An example of this state is steam from heating water or vapor from e-cigarettes.