Abstract

Recently, total inward leakage (TIL) for filtering facepiece and elastomeric half-mask respirators (EHRs) was measured according to the International Organization for Standardization (ISO) test method standard 16900-1:2014 that showed larger TIL for corn oil aerosol than for NaCl aerosol. Comparison of TIL measured for different aerosols for higher protection level respirators is lacking. The objective of this study was to determine TIL for EHRs, full-facepiece respirators, and loose-fitting and tight-fitting powered air-purifying respirators (PAPRs) using NaCl and corn oil aerosols to compare. TIL was measured for two models each of EHRs, full-facepiece respirators, and loose-fitting and tight-fitting PAPRs. After fit testing with a PortaCount (TSI, St. Paul, MN) using the Occupational Safety and Health Administration (OSHA) protocol, eight subjects were tested in the NaCl aerosol chamber first and then in the corn oil aerosol chamber, while another eight subjects tested in the reverse order. Subjects were randomly assigned to one of the two groups. TIL was measured as a ratio of mass-based aerosol concentrations inside the mask to the test chamber while the subjects performed ISO 16900-1-defined exercises using continuous sampling methods. The concentration of corn oil aerosol was measured with one light scattering photometer, alternately, and NaCl aerosol was measured using two flame photometers. Results showed the geometric mean TIL for EHR was significantly (p < 0.05) larger for corn oil aerosol than for NaCl aerosol. EHR models equipped with P100 filters showed relatively smaller TIL values than the same models with N95 filters showing that TIL was inversely related to filter efficiency. Interestingly, TIL was significantly (p < 0.05) larger for NaCl aerosol than for corn oil aerosol for PAPRs, but not for full-facepiece respirators. TIL was inversely related to fit factors of respirator types. Overall, filter efficiency and faceseal leakage determine TIL. The relative trends in TIL for the two aerosols’ test methods differ between respirator types indicating that generalization of TIL for respirator types may not be appropriate when using different test agents.

摘要

最近，根据国际标准化组织 (ISO) 测试方法标准 16900-1:2014 对过滤面罩和弹性半面罩呼吸器 (EHR) 的总向内泄漏 (TIL) 进行了测量，结果显示玉米油气溶胶的 TIL 大于氯化钠气溶胶。缺乏对较高防护级别呼吸器的不同气溶胶测量的 TIL 的比较。本研究的目的是使用 NaCl 和玉米油气溶胶来确定 EHR、全面罩呼吸器以及松配合和紧配合动力空气净化呼吸器 (PAPR) 的 TIL，并进行比较。TIL 是针对两种型号的 EHR、全面罩呼吸器以及宽松型和紧身型 PAPR 进行测量的。根据职业安全与健康管理局 (OSHA) 协议，使用 PortaCount（TSI，圣保罗，明尼苏达州）进行适合性测试后，八名受试者首先在氯化钠气溶胶室中进行测试，然后在玉米油气溶胶室中进行测试，另外八名受试者则在以相反的顺序进行测试。受试者被随机分配到两组中的一组。TIL 被测量为面罩内与测试室内基于质量的气溶胶浓度的比率，同时受试者使用连续采样方法进行 ISO 16900-1 定义的练习。玉米油气溶胶的浓度用一台光散射光度计交替测量，氯化钠气溶胶的浓度用两台火焰光度计测量。 结果显示，玉米油气溶胶的 EHR 几何平均 TIL 显着大于 NaCl 气溶胶 ( p < 0.05)。配备 P100 过滤器的 EHR 模型显示出比配备 N95 过滤器的相同模型相对较小的 TIL 值，这表明 TIL 与过滤器效率成反比。有趣的是，对于 PAPR，氯化钠气溶胶的 TIL 明显大于玉米油气溶胶的 TIL（p  < 0.05），但对于全面罩呼吸器则不然。TIL 与呼吸器类型的适合因素呈负相关。总体而言，过滤器效率和端面密封泄漏决定了 TIL。两种气溶胶测试方法的 TIL 相对趋势在呼吸器类型之间有所不同，这表明在使用不同的测试剂时，呼吸器类型的 TIL 概括可能不合适。