Review: Assessment of the qualitative fit test and quantitative single-pass filtration efficiency of disposable N95 masks following gamma irradiation

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Review: Assessment of the qualitative fit test and quantitative single-pass filtration efficiency of disposable N95 masks following gamma irradiation

Review: Assessment of the qualitative fit test and quantitative single-pass filtration efficiency of disposable N95 masks following gamma irradiation

Findings from this small study suggested that a qualitative fit test alone is unable to fully assess mask integrity and that at the doses required for sterilization, gamma radiation degrades the filtration efficiency of N95 masks.

  • A set of 3M 8210, 1805, and 9105 masks were irradiated using a cobalt-60 irradiator at the Massachusetts Institute of Technology. Three masks of each type received 0 kGy (control), 1 kGy, 10 kGy, and 50 kGy of approximately 1.3 MeV gamma radiation from the source, at a dose rate of 2.2 kGy per hour.
  • Three different particle sizes—0.3, 0.5, and 1 μm—were tested, and the single-pass filtration efficiency was measured using an optical particle counter (Aerotrak 9306; TSI Inc). The measurement system, which was not calibrated for N95 mask certification, was only used to assess the relative changes in the filtration efficiency.
  • All masks (both control and irradiated masks) passed the qualitative fit test.
  • There was statistically significant degradation of filtration efficiency for treated masks.
|2020-05-27T08:40:40-04:00May 26th, 2020|COVID-19 Literature|0 Comments

About the Author: Megan McHenry

Megan McHenry
Megan S. McHenry, MD, MS, FAAP is a pediatrician and an Assistant Professor of Pediatrics in the Ryan White Center for Pediatric Infectious Disease and Global Health at Indiana University School of Medicine. Dr. McHenry's research focuses on early childhood development in children living in resource-limited settings. This work is frequently aligned with community-engaged research and dissemination and implementation science frameworks. She primarily conducts research in collaboration with the Academic Model for Providing Access to Healthcare (AMPATH) Research Network in Kenya. Dr. McHenry currently has a career development award through the National Institutes of Health to develop a neurodevelopmental screening program for children born to HIV-infected mothers in Kenya. Dr. McHenry is also the Director of Pediatric Global Health Education and a co-Director of the Morris Green Physician-Scientist Development Program at Indiana University School of Medicine. In additional to global health lectures, she also educates residents and students on early childhood development, basic biostatistical techniques, research methodologies, and research ethics. She mentors multiple pediatric fellows, residents, and medical students interested in early childhood development within global contexts.

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