Human Nasal Mucosal Function under Four Controlled Humidities1–3

Abstract

Human nasal mucus flow was measured with a radioactive tagged particle technique in 58 young healthy subjects divided into 4 groups and exposed to 70, 50, 30, and 10 per cent relative humidity at 23° C. Each subject was measured 4 times at intervals of 2 hours and served as his own control. No change was observed in the mucus flow or in nasal airflow resistance during a stay of 8 hours at 70 per cent relative humidity and no significant difference existed among the mucus flows and nasal resistances at the 4 humidity levels. The mucus flows in the anterior and the posterior half of the nasal cavity were identical. The mucus flows in the 58 subjects were log-normal distributed with an interindividual variation far greater than the intraindividual variation. The mucus flows ranged from 0 to 2.36 cm per min, with an average of 0.48 cm per min. No relationship existed between a subject's mucus flow during one day and history of susceptibility to infections of the upper respiratory tract.