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

INTRODUCTION: Personal 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. METHODS: Portions 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. RESULTS: Ozone 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. DISCUSSION: These results suggest that ozone is a feasible strategy to disinfect N95 respirators for reuse during this and future pandemics.