NIOSHTIC-2 Publications Search
Gas and particle motion.
Aerosol measurement: principles, techniques, and applications. Willeke K, Baron PA, eds. New York: Van Nostrand Reinhold, 1993 Jan; :23-40
Aerosols consist of two components: a gas or gas mixture, most commonly air, and the particles suspended in it. The behavior of the particles within the aerosol depends to a large extent on the motion and intrinsic properties of the suspending gas. Submicrometer-sized particles, especially those <0.1 um diameter, are affected by the motion of individual gas molecules (the free molecular regime). Thus, the kinetic theory of gases is useful in understanding the behavior of these particles. Larger particles can be treated as being submersed in a continuous gaseous medium or, more broadly, a fluid (the continuum regime). The tools of gas or fluid dynamics are more useful for this size range. Intermediate-sized particles can usually be treated by an adjustment of equations from the continuum regime. This intermediate range is termed the transition or slip regime. Whether considering a molecular ensemble or a continuous fluid, the motion of the gas will largely dictate the behavior of the suspended particles. In this chapter, concepts and parameters that affect gas and particle motion will be discussed and quantified as migration and deposition parameters in specific force fields.
Aerosols; Gas-mixtures; Gases; Fluids; Behavior
Aerosol measurement: principles, techniques, and applications
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division