• Users Online: 96
  • Print this page
  • Email this page

Table of Contents
Year : 2022  |  Volume : 8  |  Issue : 1  |  Page : 79-80

An easy, efficient, and safe method to extend utilization of N95 masks: A physician's perspective

1 Department of Otorhinolaryngology, RG Kar Medical College Hospital, Kolkata, West Bengal, India
2 Department of General Surgery, All India Institute of Medical Sciences, Raipur, Chhattisgarh, India
3 Department of Obstetrics and Gynaecology, SSIMS, Bhilai, Raipur, India

Date of Submission19-Aug-2020
Date of Acceptance27-Feb-2022
Date of Web Publication30-Jun-2022

Correspondence Address:
Rubik Ray
Department of General Surgery, All India Institute of Medical Sciences, Raipur, Chhattisgarh
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJCFM.IJCFM_98_20

Rights and Permissions

How to cite this article:
Biswas D, Ray R, Biswas D. An easy, efficient, and safe method to extend utilization of N95 masks: A physician's perspective. Indian J Community Fam Med 2022;8:79-80

How to cite this URL:
Biswas D, Ray R, Biswas D. An easy, efficient, and safe method to extend utilization of N95 masks: A physician's perspective. Indian J Community Fam Med [serial online] 2022 [cited 2022 Nov 27];8:79-80. Available from: https://www.ijcfm.org/text.asp?2022/8/1/79/349393

Dear Editor,

We want to inform the readership about a relatively easy, efficient, and safe method to extend the utilization of N95 respirators from the perspective of a practicing physician. Risk of contracting infection was always an occupational hazard for doctors, but COVID-19 pandemic has taken that to unprecedented levels. N95 masks are the current cornerstone of protection against COVID-19.[1] While the common medical or surgical masks are quite abundantly available to use, studies indicate that filtration efficiency of surgical masks is quite low varying from 38.5% (with ear loops) to 71.5% (with ties behind the head/head loops), whereas for N-95 masks, it approaches 98%.[2] According to the Centers for Disease Control and Prevention, surgical masks are not considered as “respiratory protection.”[3] Moreover, it is not just the filtration capacity of the mask, also equally important is the fit of the mask to the contour of the individual's face, which is much poorer in case of surgical masks.[4]

N95 masks and personal protective equipment might be somewhat abundant in larger cities and hospitals; however, for physicians having their practice in semiurban and rural setups, attending to outpatients with a fresh N95 mask everyday, let alone after every patient, becomes quite unfeasible. Availability and financial factors among others are major limiting factors.

At present, recommendations for reuse or extending the life of N95 masks may include methods such as hot air oven and ultraviolet-sterilization, that protect the filtration efficiency of N95, but are quite inconvenient to carry out on a daily basis and outside of well-equipped bigger hospitals. Other methods such as washing with alcohol-based solution, soaps, and chlorine-based solutions are not recommended as it degrades the filtration efficiency of such masks significantly.[5] Washable masks are generally cloth-based, which may or may not have an added meltblown filter layer in between, but their filtration efficiency does not approach N95 standards, and are not indicated for handling patients where chances of exposure to COVID-19 is relatively high.

Few institutions in India including the All India Institute of Medical Sciences, Delhi,[6] are following the practice of issuing five N95 masks to its residents and faculty, to be used on a rotational basis over a period of 20 days, but this practice has not become widespread so far. The basis for this appears to be a lot of studies, which show that the surrogates of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), namely HCov-229E, and the erstwhile SARS-CoV-1 virus is inactivated mostly within a period of 5 days, when considering its survival on common inanimate surfaces such as paper, rubber, metal, ceramic, glass, and plastic.[7] While studies also claim that SARS-CoV-2 which is more similar to SARS-CoV-1, is considerably more stable than HCoV-229E and can remain viable for 6 days in dried state.[8] It was also noted by the authors that rotational use of the mask on every 6th day was becoming increasingly confusing, as it was difficult to keep track of the sequence, thereby exposing the, doctor to potential risk of unintentional use of a “wrong” mask on a “wrong” day!

This led us to improvise, to think of an simple, easy but effective way to maximize the available resources at hand. We like to call it the “day-mask policy.” Seven paper bags are taken and marked from “Monday” through “Sunday” [Figure 1]. Each bag contains one N95 and one 3-layered surgical mask. The 3-layered surgical mask is worn over the N95 mask, only to prevent gross external soiling of the N95 while clinically managing patients and also during surgeries where it is more prone to accidental body fluid splashes, so that the longevity of the N95 is prolonged. It is not advocated with an intent to provide additional filtration efficiency against COVID-19. The surgical mask, as they come cheap, may be discarded daily after use.
Figure 1: One envelope per day, each containing a N95 and a triple layered surgical mask

Click here to view

We consider the “day-mask policy” to be superior to wearing the same N95 mask for 6 days on one go with or without a cloth mask on, it as the main principle behind our “day mask policy” is to allow time for the entrapped viral particles over the outer surface of the mask to be destroyed or inactivated without the need for any active intervention. Using the same mask on consecutive days defeats this very idea and thus increases the exposure. Again, this same policy allows for the mask to be used better in regions of excess humidity, or where sweating is more, as it eliminates the factor of moisture and odor accumulation which soon becomes an issue with continuous usage.

While the maximum possible number of safe reuses for a N95 mask has still not been determined,[9] we have found that each N95 masks can usually be used in a normal working day (8–9 h approximately) for 6 days (therefore 6 such cycles), before it is rendered potentially unusable due to deformity, smell and concerns of reduced efficacy.

The “day-mask policy” makes it extremely easy to identify the “right packet for the day,” thus preventing the chance of picking the wrong mask before the virus becomes potentially unviable and noninfective. This practice not only simplifies and extends N95 mask usage, but makes it financially more feasible when we consider physicians and other health-care workers working in small setups in rural and semiurban areas. We hope that fellow physicians find this technique rational, practical, and useful.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Wang X, Pan Z, Cheng Z. Association between 2019-nCoV transmission and N95 respirator use. J Hosp Infect 2020;105:104-5.  Back to cited text no. 1
Steinbrook R. Filtration efficiency of face masks used by the public during the COVID-19 pandemic. JAMA Intern Med 2021;181:470.  Back to cited text no. 2
Available from: https://www.cdc.gov/niosh/npptl/pdfs/understanddifferenceinfographic-508.pdf. [Last accessed on 2022 Apr 29].  Back to cited text no. 3
O'Kelly E, Arora A, Pirog S, Ward J, Clarkson PJ. Comparing the fit of N95, KN95, surgical, and cloth face masks and assessing the accuracy of fit checking. PLoS One 2021;16:e0245688.  Back to cited text no. 4
Liao L, Xiao W, Zhao M, Yu X, Wang H, Wang Q, et al. Can N95 respirators be reused after disinfection? How many times? ACS Nano 2020;14:6348-56.  Back to cited text no. 5
Available from: https://www.aiims.edu/images/pdf/notice/SOP_N95_09_04_20.pdf. [Last accessed on 2022 Apr 29].  Back to cited text no. 6
Ren SY, Wang WB, Hao YG, Zhang HR, Wang ZC, Chen YL, et al. Stability and infectivity of coronaviruses in inanimate environments. World J Clin Cases 2020;8:1391-9.  Back to cited text no. 7
Rabenau HF, Cinatl J, Morgenstern B, Bauer G, Preiser W, Doerr HW. Stability and inactivation of SARS coronavirus. Med Microbiol Immunol 2005;194:1-6.  Back to cited text no. 8
Available from: https://www.cdc.gov/niosh/topics/hcwcontrols/recommendedguidanceextuse.html. [Last accessed on 2022 Apr 25].  Back to cited text no. 9


  [Figure 1]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
Article Figures

 Article Access Statistics
    PDF Downloaded22    
    Comments [Add]    

Recommend this journal