Title: particle size
Long Title: IUPAC Gold Book - particle size
DOI: 10.1351/goldbook.P04430
Status: current

Definition
To describe the size of liquid or solid particles (aerosol) the average or equivalent diameter 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.

Related Terms
- aerosol: https://goldbook.iupac.org/terms/view/A00176
- equivalent diameter: https://goldbook.iupac.org/terms/view/E02191

Source
- PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2205 (https://doi.org/10.1351/pac199062112167)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/P04430/html
- json: https://goldbook.iupac.org/terms/view/P04430/json
- xml: https://goldbook.iupac.org/terms/view/P04430/xml

Citation: Citation: 'particle size' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.P04430
License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.
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Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.
Accessed: 2026-07-26T05:51:55+00:00