Aerosol

photograph of heavy mist
Mist and fog are aerosols

An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas.[1] Aerosols can be generated from natural or human causes. The term aerosol commonly refers to the mixture of particulates in air, and not to the particulate matter alone.[2] Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of human caused aerosols include particulate air pollutants, mist from the discharge at hydroelectric dams, irrigation mist, perfume from atomizers, smoke, dust, sprayed pesticides, and medical treatments for respiratory illnesses.[3] When a person inhales the contents of a vape pen or e-cigarette, they are inhaling an aerosol, too.[4]

The liquid or solid particles in an aerosol have diameters typically less than 1 μm. Larger particles with a significant settling speed make the mixture a suspension, but the distinction is not clear-cut. In everyday language, aerosol often refers to a dispensing system that delivers a consumer product from a spray can.

Diseases can spread by means of small droplets in the breath,[5] sometimes called bioaerosols.[6] One example was the transmission of the virus that lead to the COVID-19 pandemic.[7]

  1. ^ Hinds 1999, p. 3.
  2. ^ Seinfeld J, Pandis S (1998). Atmospheric Chemistry and Physics: From Air Pollution to Climate Change (2nd ed.). Hoboken, New Jersey: John Wiley & Sons. p. 97. ISBN 978-0-471-17816-3.
  3. ^ Hidy 1984, p. 254.
  4. ^ "Tobacco: E-cigarettes". www.who.int. Retrieved 2021-08-24.
  5. ^ Hunziker, Patrick (2021-10-01). "Minimising exposure to respiratory droplets, 'jet riders' and aerosols in air-conditioned hospital rooms by a 'Shield-and-Sink' strategy". BMJ Open. 11 (10): e047772. doi:10.1136/bmjopen-2020-047772. ISSN 2044-6055. PMC 8520596. PMID 34642190.
  6. ^ Fuller, Joanna Kotcher (2017-01-31). Surgical Technology – E-Book: Principles and Practice. Elsevier Health Sciences. ISBN 978-0-323-43056-2.
  7. ^ McNeill VF (June 2022). "Airborne Transmission of SARS-CoV-2: Evidence and Implications for Engineering Controls". Annual Review of Chemical and Biomolecular Engineering. 13 (1): 123–140. doi:10.1146/annurev-chembioeng-092220-111631. PMID 35300517. S2CID 247520571.