[The influence of face masks and a nasal nozzle on nasal airflow]

In an attempt to detect the influence of various kinds of face masks and a nasal nozzle on nasal airflow, we made measurements of nasal resistance by a head-out body plethysmograph with or without the masks on the face or the nozzle to the nostril of the normal adult subjects. The mean values of nasal resistance with the masks differed from the mean values without the masks significantly. No significant difference between values with and without the nozzle was found. The coefficient variations of 40 consecutive measurements of nasal resistance with the masks or the nozzle had wider ranges than those without the apparatuses. But the variation due to the nozzle was the minimum in the apparatuses.