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HOME-FIT: HOmemade Masks for Everyone Fit and Improvement Testing
CANDICE SIRMOLLO, Karl Haro von Mogel, Don Collins, Mikeal Roose, University of California, Riverside
Abstract Number: 521
Working Group: The Role of Aerosol Science in the Understanding of the Spread and Control of COVID-19 and Other Infectious Diseases
Abstract
Homemade masks are commonly used to protect the general public from the spread of infectious respiratory diseases such as COVID-19 when surgical masks and N95 respirators are in short supply or are limited to healthcare workers. The usage of masks is recognized to play an integral role in reducing droplet transmission from the wearer to others, but can also reduce airborne transmission from the surrounding environment to the wearer. Airborne transmission via virus-containing particles can be an important form of transmission for many types of infectious diseases and its mechanisms should be considered when selecting a mask. Mask designs and materials vary significantly, resulting in a wide range of particle filtration and breathability levels. Several recent studies have investigated the filtration efficiency of particles through mask materials alone, providing the public with better informed guidance on what materials to select for a mask. However, very little is understood concerning different mask designs and the fit of the masks on different face shapes and sizes. To investigate this critical knowledge gap, testing has been conducted with human volunteers to evaluate different mask designs. Tests were conducted while various exercises are performed that are representative of real-world activities including normal breathing, deep breathing, turning head side to side, raising head up and down, talking out loud, grimacing, and bending over. Common mask designs have been tested for different face shapes and sizes, as well as variations of mask sizes, nose bridges, elastic vs. tie options, and fabric types. The size dependence of the filtration efficiency of particles between 0.01 and 1 µm that are able to leak inside of different mask designs are investigated. The results of this testing have guided the development of improved mask designs to provide optimal protection from the transmission of airborne respiratory diseases.