NIOSHTIC-2 Publications Search

The effect of ambient aerosol concentration and exercise on Portacount quantitative fit factors.

Zhuang Z; Lawrence R; Campbell D; Coffey C
American Industrial Hygiene Conference and Exposition, May 8-13, 2004, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 2004 May; :83
The PortaCount is a quantitative fit-test instrument which uses ambient aerosol to determine respirator fit. Ambient aerosol concentration levels vary greatly among workplaces. The standard fit test currently uses eight one-minute exercises. Considerable time and financial commitments are needed to select a properly fitting respirator for a given worker. The purposes of this study were to determine: (1) if PortaCount fit factors are affected by ambient aerosol concentration, and (2) if any of the exercises are the most critical in determining the overall fit factor. Fit-test data for 30 elastomeric and filtering-facepiece respirator models from a recent NIOSH study were analyzed. Each model was tested on a 25-subject panel using the PortaCount and seven exercises. The analyses determined: (1) if fit factor varies among five levels of ambient aerosol concentration, (2) the frequency of each exercise having the lowest within-fit-test fit factor, and (3) the average within-fit-test ratio of each exercise fit factor to the highest fit factor among all exercises. Ambient aerosol concentration had no practical effect on fit factor. "Reading," "bending," and "moving head up/down" exercises had the lowest fit factor in about 66% of the tests. They also had the lowest average within-fit-test ratios of exercise fit factor to the highest fit factor (0.56, 0.62, and 0.67, respectively). Fit factors for each exercise were found to be highly correlated with fit factors for each of the other six exercises. There was no significant fit-factor difference between the first and second normal breathing exercises. We conclude that the fit test pass/fail criterion need not be adjusted for ambient aerosol concentration level and that "reading," "bending," and "moving head up/down" are the three most critical exercises in determining the overall fit factor. Further study is needed to determine if fit-test procedures can include only these three exercises.
Aerosols; Quantitative-analysis; Respirators; Respiratory-protective-equipment; Models
Publication Date
Document Type
Fiscal Year
NIOSH Division
Priority Area
Research Tools and Approaches: Control Technology and Personal Protective Equipment
Source Name
American Industrial Hygiene Conference and Exposition, May 8-13, 2004, Atlanta, Georgia
Page last reviewed: August 26, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division