NIOSHTIC-2 Publications Search

Risk-based selection of respirators against infectious aerosols: application to anthrax spores.

Nicas M; Neuhaus J; Spear RC

J Occup Environ Med 2000 Jul; 42(7):737-748

https://doi.org/10.1097/00043764-200007000-00009

20024656

This article presents two methods for estimating infection risk among individuals wearing air-purifying respirators against airborne pathogens, with the overall aim of selecting appropriate respiratory protection. Necessary data inputs are the parameters for the ambient pathogen concentration distribution, the respirator penetration distribution, and the infectious dose distribution, along with the breathing rate, duration of a respirator use period, and the number of use periods. The first method assumes that the pathogen does not exhibit a cumulative dose effect, whereas the second accounts for a cumulative dose effect. The methods are illustrated with hypothetical scenarios involving Bacillus anthracis (anthrax) spores. Available data suggest that anthrax spores would exhibit a cumulative dose effect for multiple exposures occurring close in time, as would likely affect personnel responding to a bioterrorist release. The analysis shows that failure to account for a cumulative dose effect when present leads to underestimating infection risk. Three types of air-purifying respirators are compared for their predicted efficacy in reducing the risk of inhalation anthrax. Although uncertainty analyses are not performed, a general conclusion is that a full-facepiece powered air-purifying respirator would be the best air-purifying device for responding to an anthrax spore release. Because such respirators would not prevent all personnel from inhaling an infectious dose, it would be advisable for users not previously vaccinated against anthrax to receive post-exposure prophylactic therapy.

Statistical-analysis; Models; Respirators; Air-contamination; Respiration; Air-purification; Air-purifiers; Air-purifying-respirators; Personal-protective-equipment; Protective-equipment; Respiratory-protection; Respiratory-protective-equipment; Microorganisms; Bacterial-dusts

Dr Mark Nicas, Center for Occupational and Environmental Health, School of Public Health, University of California, Berkeley, CA 94720

JOEMFM

20000701

Journal Article

mnicas@berkeley.edu

412603

Grant

2000

Grant-Number-R01-OH-003570

7

1076-2752

Research Tools and Approaches: Control Technology and Personal Protective Equipment

Journal of Occupational and Environmental Medicine

CA

University of California, Berkeley, California