Effects Of Powered Air-purifying Respirators On Relative Inspiratory Time During Rest And Exercise

Powered air-purifying respirators (PAPRs) approved by the National Institute for Occupational Safety and Health (NIOSH) are preferred respiratory protection among air-purifying respirators due to low inhalation resistance and decreased effective dead space. PURPOSE: This study evaluated effects from PAPR hood size (small, medium, and large loose-fitting hoods) and hood type (loose-fitting hood and tight-fitting mask) on relative inspiratory time (expressed as duty cycle) during standing rest and treadmill exercise. METHODS: Men (n=12) and women (n=12) were calibrated (same absolute energy expenditure) on a treadmill at VO2 = 1, 2, and Max (3.0 for men, 2.7 for women) L/min (STPD). Four NIOSH-approved PAPRs from different manufacturers with HEPA filters were randomly selected and worn by each participant for four minutes at standing rest and four minutes at each energy expenditure. Results were averaged during the last minute of each activity period and expressed for both men and women. PAPR results were compared to exercise trials using only the instrument mask (baseline). Repeated measures ANOVA for duty cycle (inspiratory time/total time each breath, x100) was used for Table 1. RESULTS: