particle size

in atmospheric chemistry
To describe the size of liquid or solid particles (@[email protected]) the average or @[email protected] is used. For non-spherical particles collected in an impactor, for example, the aerodynamic diameter of a particle of arbitrary shape and density refers to the size of a spherical particle of unit density that would deposit on a given impactor surface.
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2205 [Terms] [Paper]