Nasal-air conditioning]

We present a review of nasal-air conditioning, a process essential to undisturbed gas exchange and cleansing of the respiratory mucosa in the nose.A selective literature review was made on the basis of in vivo measurements and computer simulation of the upper airways as well as the authors' own clinical and experimental data.Healthy subjects normally breathe through the nose, although the nasal airways have significantly higher airway resistance compared to the oral cavity, which is opened for breathing during exercise, in the case of nasal airway blockage, or in allergic rhinitis. In addition to olfaction, the main tasks of nasal breathing include: cleansing, defense, and conditioning (i.e., humidification and heating). The current knowledge of nasal conditioning processes will be discussed. In addition, research activities of particular relevance for diagnosis and intervention in various pathologies of the upper airways will be presented.