Gouttelettes

Gouttelettes, the French term for small liquid droplets, refer to tiny spheres of liquid expelled into air or onto surfaces. In respiratory contexts they range in size from roughly 0.5 to 100 micrometers in diameter. Size influences how they behave: larger droplets tend to settle quickly, while smaller ones can evaporate and persist as airborne particles called droplet nuclei.

Formation and sources: They are produced by speaking, singing, coughing, sneezing, or technical devices such as spray nozzles and humidifiers. Breath and saliva mixing generate particles containing microorganisms or chemical substances.

Physical behavior and transmission: Droplets larger than about 5–10 micrometers usually travel short distances (about 1–2 meters) before settling; smaller droplets may be carried by air currents and linger longer. Evaporation can shrink droplets into nuclei, which can remain suspended and potentially participate in airborne transmission. Humidity, temperature, and air flow influence their fate.

Health and safety context: In medicine and public health, gouttelettes are recognized as a route for transmission of respiratory infections. Preventive measures include masks, physical distancing, ventilation, air filtration, hand hygiene, and surface cleaning to reduce contact with contaminated droplets.

Other contexts: In science and industry, gouttelettes are studied in aerosol science, spray coating, and inhalation therapies. Their size distribution, composition, and generation mechanisms determine deposition in the respiratory tract and the effectiveness of sprays and aerosols.