Abstract:
In addition to the traditional gas/liquid/solid division of the physical states of matter, there is the combination of the three: aerosols. Aerosols are solid or liquid particles so small that they make a stable suspension in a gas, usually air. They are comprised of stable airborne particles less than 100 micrometers in aerodynamic width, whereas particles about that size range settle relatively quickly (Baron, 2001).
Aerosols are found in almost every environment. They may be homogenous particles of a particular chemical, such as a mist of diesel particles, or metal fumes condensing above a foundry operation. Or, they may be heterogeneous clusters of solids attached to water droplets or to dusty debris, such as airborne microscopic raindrops containing tiny soot particles accumulated during their journey from cloud to earth. Alternatively, an aerosol particle may be airborne dust contaminated with Hantavirus originating from rodent droppings. This would be included in a subclass called bioaerosols, which are Airborne suspensions of solid or liquid particles that contain or are derived from living organisms (ACGIH, 2005).
Such bioaerosols are of particular public health concern because they are the vectors for many diseases, and in addition may be artificially produced and dispersed for purposes of profit, war, and terrorism. Classed among biological weapons, bioaerosols are heavily regulated.
Taken from the beginning of thesis.