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Extending The Lifetime of N95 Masks - Recommendations For The Healthcare Industry

By Kirsten Koehler And Ana Rule | April 2, 2020

Kirsten Koehler, PhD
Associate Professor
Environmental Health and Engineering
Johns Hopkins Bloomberg School of Public Health 

Ana Rule, PhD
Assistant Professor
Environmental Health and Engineering
Johns Hopkins Bloomberg School of Public Health

There is a severe global shortage of supply of personal protective equipment (PPE), which is affecting the ability of hospitals and clinics to respond to the COVID-19 pandemic. PPE is one of the ways in which hospitals protect their most valuable resource: health care workers who are at the frontlines of the disease.

Recent WHO guidance recommends several ways in which health care settings can optimize availability of PPE. These guidelines include minimizing PPE need, appropriate use of PPE, and coordination of the supply chain. Unfortunately, the need has reached a critical point in which these guidelines are not enough and hospitals all over the world are looking for ways to extend the life of existing PPE.

One of the most critical pieces of PPE for a disease like COVID-19, which has the potential to be transmitted through very small droplets,1-3 are N95 respirators. These respirators are made of special material that removes at least 95% of these droplets. They’re also manufactured to fit with a tight seal around the nose and mouth so air and viral particles can’t get around the side of the respirator.

There are several ways to extend the availability of N95 respirator supplies, if we reuse them until they are visibly soiled, structurally damaged, or hard to breathe through.

Several decontamination methods have been proven to disinfect masks and respirators for reuse. Heat treatment (70oC for 30 min), UV-C radiation, and treatment with hydrogen peroxide gas have been shown to disinfect masks. (See this report from Stanford Medicine, this protocol from Nebraska Medicine, and this one from Duke Health for more information.)

Another way to safely reuse masks and respirators (both N95 and surgical masks) is to assign seven of them, one for each day of the week, to those health care workers who can reuse the same mask or respirator throughout the day. At the end of each day each mask or respirator is stored in a separate breathable paper bag at room temperature. Write the name and date on each bag to keep track of time in storage. Wait at least 7 days before reusing the same mask. Time will deactivate the virus between uses.

Continue to follow best practices for 95 mask use. Masks conform to the face of individuals, so masks should be labeled and returned to the same individual for reuse to ensure a good fit. N95 mask use is not recommended for individuals, and individuals should not attempt to disinfect masks at home.


  1. van Doremalen N, Bushmaker T, Morris DH, et al. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV- New England Journal of Medicine. 2020.
  2. Brosseau L. COMMENTARY: COVID-19 transmission messages should hinge on science. Published 2020. Accessed.
  3. Santarpia JL, Rivera DN, Herrera V, et al. Transmission Potential of SARS-CoV-2 in Viral Shedding Observed at the University of Nebraska Medical Center. medRxiv. 2020:2020.2002023.20039446.
  4. Alex W H Chin, Julie T S Chu, Mahen R A Perera, Kenrie P Y Hui, Hui-Ling Yen, Michael C W Chan, Malik Peiris, Leo L M Poon, Stability of SARS-CoV-2 in different environmental conditions, The Lancet Microbe, 2020.