Cloth Face Mask Fit and Functionality for Children 4-6 Years Old

Abstract

IRB exemption approval. Of the three participants, the 6-year-old boy Size 7 and a head form in size 8R (based on ASTM D6458-12) 3D printed from the scan of a sixyear-old boy from Size North America dataset were included in the fit analysis. The selection of the scan was based on 3D-printability of the ears in consideration of all the head anthropometry data in a normative band. The two heads were scanned with a Structure sensor, capturing their faces with and without wearing the eight purchased commercial face masks. Visual fit analyses then conducted by two researcher expert-judges evaluated set and ease using a 5-point Likerttype rating scale (1=too tight, 3=good fit, 5=too loose). Face masks patterns were traced and imported to Adobe Illustrator and ImageJ to illustrate the nested patterns and obtain their surface area. Chi-square non-parametric test were used for statistical analysis with JMP Pro 15.0.0 software. Fabric performance for breathability and FE was evaluated on deconstructed mask samples. Multilayer samples were assembled in the sequence of the original mask. Air permeability was measured following ASTM D737-18. A simulated breathing apparatus consisting of a large animal respirator, aerosol generator, filter holder, and multi-channel particle counter was employed to assess the exhaled aerosol capture of 0.3 μm, 0.5 μm, and 1.0 μm sized particles by the various flat fabric samples. Samples were weighed by their individual layers before testing, directly after testing (wet), and 24 hours after testing (dry). Wet Pickup was calculated as a ratio of the difference between the wet and dry weights and the initial weight. Results, Discussion, and ConclusionResults of this study indicate issues with the fit, filtration, size, wear, and comfort of masks for children ages 4-6 including poor overall fit leading to slippage from proper positioning and fogging of glasses, thermal and ear discomfort, and difficulty with donning/doffing. From the market research and Qualtrics survey, the most common mask attributes were a shaped style, stretch ear loops, two layers of woven cotton, and an all-over surface print. Masks with a fitted shape around the nose, mouth and under chin coverage were most preferred, and those with highest coverage area were found to provide better fit based on results from the structured set and ease analysis of scanned heads. Evaluation of FE and air permeability showed a weak correlation between aerosol capture and breathability. No significant difference in wet pickup was measured between masks made of hydrophobic materials and masks made of hydrophilic materials, except for the 3-layered tightly woven cotton poplin mask. A balance between breathability and FE is impacted by the types of mask materials and number of layers, including moisture retention against the wearer's face, overall thermal comfort, and protection. Concerns of poor fit, comfort, and breathability among commercially available children's face masks are consistently indicated by these collective results. For the fit a...