A material such as a salt or a drug is hygroscopic if it absorbs water vapour from the air when the relative humidity (RH) of the air is larger than a certain value specific for this material. A material is non-hygroscopic, if it doesn’t absorb water vapour at RH’s below saturation. According to this definition a salt or drug is hygroscopic, that is all soluble in water. Hygroscopic materials are widely used in medicine for therapeutic and diagnostic purposes. Hygroscopic materials are present in atmospheric aerosol particles. High concentrations, mainly NaCl, are found near to the sea (Keith and Arons, 1954; Winkler and Junge, 1972). Continental aerosols also have a hygroscopic fraction (Hänel, 1976; Hicks and Megaw, 1985; McMurry and Stolzenburg, 1989; Busch et al., 1994; Busch, 1995). Hygroscopic aerosols play an important role in the formation of clouds (Pruppacher and Klett, 1980).
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- Deposition of Hygroscopic Aerosol Particles in the Lungs
George A. Ferron
- Springer Netherlands
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