Assessment of Proficiency of N95 Mask Donning Among the General Public in Singapore

This cross-sectional study examines factors associated with proper use of N95 masks among residents of Singapore.


Introduction
With the advent of the coronavirus disease 2019 (COVID-19) pandemic, mask-wearing among the general public has become commonplace, leading to a worldwide shortage. 1However, there is little data on mask-wearing proficiency in the general public.A single study performed in the US after Hurricane Katrina, when individuals donned masks for mold remediation, found that only 24% of participants demonstrated proper technique. 2Incorrectly worn masks may not confer effective protection against COVID-19.
We conducted this cross-sectional study to evaluate the proficiency of members of the Singapore public in wearing N95 masks, which the local government distributed to households in 2014 as part of an emergency preparedness program 3 targeted at episodes of haze.The duck-bill foldable N95 mask (3M VFlex 9105) was selected for ease of mailing and was distributed along with pictorial instructions.

Methods
The institutional review board of the National University of Singapore granted approval for our study.
Verbal informed consent was obtained from all participants, and a participant information sheet was provided.This study is reported following Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.
We conducted a cross-sectional study in the Jurong district in Singapore from February 9 to 15, 2015.Participants were recruited by simple random sampling without replacement.Inclusion criteria were Singapore citizens or permanent residents aged 21 years or older who lived in Singapore in June through July 2013 (during a severe episode of transboundary haze) and who were physically able to independently don the N95 mask.N95 masks, with accompanying multilingual pictorial instructions, were given to respondents.These masks and instruction sheets were of the same model as those mailed out to Singapore residents in 2014.The participant was then asked to put on the mask, with no prompting to refer to the instruction sheet.Interviewers administered a visual mask fit (VMF) test 2 and a user seal check following the manufacturer's instructions. 4Our primary outcome was passing the VMF test.
Pearson χ 2 tests and Welch t test were used for bivariate analyses, and a log-binomial regression model was used for multivariable analyses.Data were analyzed using R statistical software (R Project for Statistical Computing).P values were 2-sided, and statistical significance was set at .05. Analysis was conducted from February to March 2015.

Discussion
Our study found a low N95 VMF pass rate of 12.6%.The observation that reading pictorial instructions was not associated with increased VMF pass rates may suggest an inherent complexity to N95 mask wearing.Limitations of this study include nonresponse and recall bias.
These findings support ongoing recommendations against the use of N95 masks by the general public during the COVID-19 pandemic. 5N95 mask use by the general public may not translate into effective protection but instead provide false reassurance.Beyond N95 masks, proficiency among the general public in donning surgical masks needs to be assessed.Policy measures that encourage mask use in the general public must be coupled with effective training materials beyond instruction leaflets, which our study and a 2013 study by Harber et al 6 found to be inadequate.Other public health measures, such as social distancing, handwashing, and self-isolation when ill, are also critical.

Table 1 .
Demographic Characteristics of Study Participants a Missing data for 1 participant.