@article{armistead_dandekar_mathews_smith_gaskill_girase_ormond_2026, title={Development of an animatronic headform test method for determining the efficacy of medical masks and barrier face coverings—part 1: total filtration efficacy}, url={https://doi.org/10.1080/15459624.2026.2612992}, DOI={10.1080/15459624.2026.2612992}, abstractNote={The effectiveness of face coverings against respiratory viruses is crucial for public health but often lacks realistic performance assessments of protection and comfort. In this study, a system-level test method was developed using an animatronic headform to incorporate fit and dynamic wear into the assessment of total filtration efficacy of medical masks and barrier face coverings. Six commercially available products were evaluated, including an N95 respirator as the control. Total filtration efficacy was calculated from differential particle counts recorded inside and outside of face coverings each minute. The baseline method was able to statistically differentiate between products to a difference in means of 5% at a particle size of 0.3 μm optical diameter. The 16 and 28 L/min sinusoidal flow rates significantly impacted total filtration efficacy, as did the influence of headform movement and duration of wear for select products. There were statistical differences between operators at both flow rates for the KN95 and surgical style masks that were difficult to don consistently, highlighting the variability in performance due to fit. However, the product type remained the most significant cause of variance in the method at 66.10%, demonstrating that the headform test method was able to repeatedly and reproducibly evaluate the efficacy of various face coverings. Furthermore, there were significant decreases in filtration when the facepiece was not sealed properly due to poor fit. This highlights the importance of evaluating these source control devices, including barrier face coverings and public use of medical masks, as they are intended to be worn to incorporate their fit into the reported results.}, journal={Journal of Occupational and Environmental Hygiene}, author={Armistead, Melissa and Dandekar, Anuja and Mathews, Marc and Smith, Madilynn and Gaskill, Mark and Girase, Arjunsing and Ormond, R. Bryan}, year={2026}, month={Feb} }
 @article{armistead_kiryaman_dandekar_gaskill_mathews_girase_ormond_2026, title={Development of an animatronic headform test method for determining the efficacy of medical masks and barrier face coverings—part 2: validation study}, url={https://doi.org/10.1080/15459624.2026.2612983}, DOI={10.1080/15459624.2026.2612983}, abstractNote={There is a need for a realistic method to evaluate the performance of barrier face coverings and medical masks in the wake of growing respiratory concerns among the general public. In this study, the previous animatronic headform test method was optimized to evaluate the total filtration efficacy and breathing resistance of 12 products during a 10-minute simulated fit test. These products included three respiratory devices, three medical masks, and six barrier face covering styles. The revised method was able to differentiate between products with total filtration efficacies ranging from 14% to 93%, down to a difference in means of 2% at 0.3 μm optical diameter. The impact of fit was illustrated by the increase in total filtration efficacy and breathing resistance across all three medical masks when the ear loops were tightened. The coefficient of variation for each product fell below 20% at 0.3 μm optical diameter, indicating good measurement stability. A second operator conducted an intra-lab validation to determine the method's reliability. This analysis confirmed the improved repeatability and reproducibility of the headform test method, which was shown to effectively evaluate the total filtration efficacy of respiratory products as a system in a controlled laboratory setting. However, more research is needed to improve the sensitivity of the breathing resistance measurements. Comparison to the ASTM F3502-21 Standard Specification for Barrier Face Coverings highlighted the differences between evaluating these products as a sealed system or as they are intended to be worn, with an overall decrease in total filtration efficiency and breathing resistance due to leakage when evaluated on the headform.}, journal={Journal of Occupational and Environmental Hygiene}, author={Armistead, Melissa and Kiryaman, Didem and Dandekar, Anuja and Gaskill, Mark and Mathews, Marc and Girase, Arjunsing and Ormond, R. Bryan}, year={2026}, month={Feb} }