Center for Health-Related Aerosol Studies, Department of Environmental and Public Health Sciences, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267, USA.
Critical Fit Technologies LLC, 1 John Hoft Rd., Tisbury, MA 02568, USA.
Ann Work Expo Health. 2023 Jan 12;67(1):50-58. doi: 10.1093/annweh/wxac051.
Throughout the COVID-19 pandemic, hundreds of millions of people worldwide have become new users of respiratory protective devices. Facemasks and KN95 respirators utilizing an ear loop straps system (ELSS) have recently become popular among occupational and non-occupational populations. Part of this popularity is due to the ease of wearability as compared with traditional devices utilizing two headbands, one worn over the head and the other behind the neck-a universal strap system used in NIOSH-certified N95 filtering facepiece respirators (FFRs). Some users convert the two-strap configuration to an adjustable ELSS. The first objective of this pilot study was to quantitatively characterize how such a conversion impacts the respirator fit. Additionally, a novel faceseal (NFS) technology, which has been previously demonstrated to enhance the fit of N95 FFRs, was deployed to modify the ELSS-converted N95 FFRs. The second objective of this study was to quantify the fit improvement that results from adding the NFS to the ELSS. The study was conducted by performing the Occupational Safety and Health Administration (OSHA)-approved quantitative fit testing (QNFT) on 16 human subjects featuring different facial shapes and dimensions. Three models of cup-shaped N95 FFRs were tested in three versions: the standard version with manufacturer's strap system, the ELSS-converted, and the ELSS-converted version modified by adding the NFS. QNFT demonstrated that the fit of an N95 FFR featuring the traditional/standard headbands strap system is negatively impacted when this system is converted to an ELSS. The fit of an ELSS-converted respirator can be significantly improved by the addition of the NFS. We found that the FFR model and the strap system version are significant factors affecting the QNFT-determined respirator fit factor (FF), as well as the OSHA QNFT pass rate (FF ≥100). The findings suggest that the current NFS, if further improved, has a potential for developing a 'universally fitting' ELSS-equipped N95 FFR that can be used by the general public, the vast majority of whom do not have access to OSHA fit requirements.
在整个 COVID-19 大流行期间，数亿人成为呼吸防护设备的新用户。耳带式系统（ELSS）的口罩和 KN95 呼吸器最近在职业和非职业人群中变得流行。这种流行的部分原因是与传统设备相比，它具有佩戴方便的特点，传统设备使用两条头带，一条戴在头上，另一条戴在脖子后面——这是 NIOSH 认证的 N95 过滤式面罩呼吸器（FFR）中使用的通用带系统。一些用户将双带配置转换为可调节的 ELSS。这项初步研究的第一个目标是定量描述这种转换如何影响呼吸器的贴合度。此外，还部署了一种新的面部密封（NFS）技术，该技术已被证明可以增强 N95 FFR 的贴合度，用于修改转换为 ELSS 的 N95 FFR。本研究的第二个目标是量化添加 NFS 到 ELSS 所带来的贴合度改进。这项研究通过对 16 名具有不同面部形状和尺寸的人体受试者进行职业安全与健康管理局（OSHA）批准的定量贴合测试（QNFT）来进行。测试了三种杯形 N95 FFR 模型，有三种版本：带有制造商的带系统的标准版本、转换为 ELSS 的版本以及通过添加 NFS 进行修改的 ELSS 转换版本。QNFT 表明，当传统/标准头带带系统转换为 ELSS 时，带有传统/标准头带带系统的 N95 FFR 的贴合度会受到负面影响。通过添加 NFS，可以显著提高 ELSS 转换呼吸器的贴合度。我们发现，FFR 模型和带系统版本是影响 QNFT 确定的呼吸器贴合因子（FF）以及 OSHA QNFT 合格率（FF≥100）的重要因素。研究结果表明，如果进一步改进当前的 NFS，它有可能开发出一种“通用贴合”的配备 ELSS 的 N95 FFR，可供大多数无法获得 OSHA 贴合要求的公众使用。
