Physiologic and subjective effects of respirator mask type.
Harber P; Beck J; Brown C; Luo J
Am Ind Hyg Assoc J 1991 Sep; 52(9):357-362
This study was performed as part of a multiyear research project assessing the physiologic, subjective, and psychophysical effects of respirators. Fourteen volunteers (seven men and seven women, 20 to 39 years old) participated in three sessions of testing, each of which included exercise in a controlled laboratory setting using a bicycle ergometer and in an outdoor shaded field course where the subject walked on the level or on a slight incline in a standardized fashion. The results reported here are from the outdoor sessions only. Respirator designs evaluated included no respirator (NR), full face mask dual cartridge with no nasal deflector (FN), full face mask respirator with nasal deflector (FD), and a powered air purifying respirator (PA). Respiratory inductive plethysmography and subjective responses by two visual analog scales were used to measure physiologic effects. There were significant effects of airflow path design on the physiologic parameters of ventilation, tidal volume, and mean flow rate. FN and FD respirators both showed increased tidal volume relative to the NR condition. PA tidal volume was similar to the NR value. Mean flow rate and ventilation data were similarly affected. Inspiratory time was increased and the respiratory rate decreased by all respirators. The mean inspiratory flow rate was increased by the nonpowered full face masks. Subjective measures showed that all three respirator loads resulted in decreases in the estimated ability to continue working and increases in reported discomfort. The PA had less physiologic impact than the nonpowered models but did not show any significant subjective benefit. The authors suggest that alternative respirator designs should be evaluated for both their physiologic and subjective effects.
NIOSH-Publication; NIOSH-Grant; Respirators; Personal-protective-equipment; Respiratory-protective-equipment; Breathing; Equipment-design; Physiological-testing; Physical-exercise
Medicine University of California School of Medicine Los Angeles, Calif 90024
American Industrial Hygiene Association Journal
University of California Los Angeles, Los Angeles, California