Disinfection of Pseudomonas aeruginosa from N95 respirators with ozone: a pilot study

• Published in: BMJ open respiratory research Vol. 8; no. 1; p. e000781
• Main Authors: Manning, Edward P, Stephens, Matthew D, Dufresne, Sylvie, Silver, Bruce, Gerbarg, Patricia, Gerbarg, Zach, Dela Cruz, Charles S, Sharma, Lokesh
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01-01-2021; BMJ Publishing Group
• Subjects: Bacteria; Coronaviruses; COVID-19; Disease control; Efficiency; Humidity; Masks; Medical supplies; Organisms; Personal protective equipment; Respiratory Infection; Severe acute respiratory syndrome coronavirus 2; Tensile strength; Viruses; United States > US; occupational lung disease; viral infection; respiratory infection
• ISSN: 2052-4439; 2052-4439
• DOI: 10.1136/bmjresp-2020-000781

IntroductionPersonal protective equipment shortages require the reuse of N95 respirators. We sought the necessary conditions for ozone to disinfect N95 respirators for reuse and the effects of multiple cycles of exposure.MethodsPortions of 3M 1870 N95 respirators were exposed to ozone at 400 ppm with 80% humidity for 2 hours to determine effectiveness of ozone on killing Pseudomonas aeruginosa. Entire 3M 1870 N95 respirators were exposed to five cycles of 400 ppm with 80% or higher humidity for 2 hours then evaluated for ozone’s effects on airflow resistance, filtration efficiency, strap strength and quantitative fit.ResultsOzone exposure disinfected 3M 1870 N95 respirators heavily inoculated with P. aeruginosa. Ozone exposure did not negatively affect the airflow resistance, filtration efficiency, strap strength or fit of the 3M 1870 N95 respirator.DiscussionThese results suggest that ozone is a feasible strategy to disinfect N95 respirators for reuse during this and future pandemics.