Face mask fit modifications that improve source control performance

Abstract

BACKGROUND During the COVID-19 pandemic, face masks are used as source control devices to reduce the expulsion of respiratory aerosols from infected people. Modifications such as mask braces, earloop straps, knotting and tucking, and double masking have been proposed to improve mask fit however the data on source control are limited. METHODS The effectiveness of mask fit modifications was determined by conducting fit tests on human subjects and simulator manikins and by performing simulated coughs and exhalations using a source control measurement system. RESULTS Medical masks without modification blocked ≥56% of cough aerosols and ≥42% of exhaled aerosols. Modifying fit by crossing the earloops or placing a bracket under the mask did not increase performance, while using earloop toggles, an earloop strap, and knotting and tucking the mask increased performance. The most effective modifications for improving source control performance were double masking and using a mask brace. Placing a cloth mask over a medical mask blocked ≥85% of cough aerosols and ≥91% of exhaled aerosols. Placing a brace over a medical mask blocked ≥95% of cough aerosols and ≥99% of exhaled aerosols. CONCLUSION Fit modifications can greatly improve the performance of face masks as source control devices for respiratory aerosols.

High efficacy of layered controls for reducing exposure to airborne pathogens

“…44 Masks can be further adjusted to improve fit. 45 Reductions in risk will likely be greater than reported in this study if either party is wearing an N95 respirator 43 or layering a wellfitting cotton mask on top of a non-medical surgical mask. 46 While the present modeling study is intended to provide mechanistic insights into the impact of nonpharmaceutical interventions on airborne transmission of pathogens, the modeling framework is intentionally idealized.…”

A conformable sensory face mask for decoding biological and environmental signals

“…This good reliability is attributed to the low aspect ratio of the pillar (0.7) in the adhesion layer, which makes it less likely to collapse during the attaching and detaching cycles 33 . The adhesion requires an improved understanding of the factors related to face mask non-compliance, gathered in the form of feedback and data from users under real-world scenarios, as well as proactive conformable decoding of this information 19,20 . Considering the difficulty in self-assessing the fit quality and the prevalence of counterfeits, providing real-time fit quality feedback directly to users is also of great value 9 .…”

What We Are Learning from COVID-19 for Respiratory Protection: Contemporary and Emerging Issues

“…Thus, surgical masks alone do not provide effective inward protection against bioaerosols [ 53 ]. However, they can significantly reduce outward leakage of droplets which makes them popular for source control as it reduces the spread of viruses [ 58 , 59 ].…”