The aim of this study was to develop a new method to measure respirator protection factors for aerosol particles using portable instruments while workers conduct their normal work. The portable instruments, including a set of two handheld condensation particle counters (CPCs) and two portable aerosol mobility spectrometers (PAMSs), were evaluated with a set of two reference scanning mobility particle sizers (SMPSs). The portable instruments were mounted to a tactical load-bearing vest or backpack and worn by the test subject while conducting their simulated workplace activities. Simulated workplace protection factors (SWPFs) were measured using human subjects exposed to sodium chloride aerosols at three different steady state concentration levels: low (8x103 particles/cm3), medium (5x104 particles/cm3), and high (1x105 particles/cm3). Eight subjects were required to pass a quantitative fit test before beginning a SWPF test for the respirators. Each SWPF test was performed using a protocol of five exercises for 3 min each: (1) normal breathing while standing; (2) bending at the waist; (3) a simulated laboratory-vessel cleaning motion; (4) slow walking in place; and (5) deep breathing. Two instrument sets (one portable instrument {CPC or PAMS} and one reference SMPS for each set) were used to simultaneously measure the aerosol concentrations outside and inside the respirator. The SWPF was calculated as a ratio of the outside and inside particles. Generally, the overall SWPFs measured with the handheld CPCs had a relatively good agreement with those measured with the reference SMPSs, followed by the PAMSs. Under simulated workplace activities, all handheld CPCs, PAMSs, and the reference SMPSs showed a similar GM SWPF trend, and their GM SWPFs decreased when simulated workplace movements increased. This study demonstrated that the new design of mounting two handheld CPCs in the tactical load-bearing vest or mounting one PAMS unit in the backpack permitted subjects to wear it while performing the simulated workplace activities. The CPC shows potential for measuring SWPFs based on its light weight and lack of major instrument malfunctions.

中文翻译：

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一种使用便携式仪器在模拟工作场所环境中测量呼吸器对气溶胶颗粒的保护系数的技术。

本研究的目的是开发一种新方法，在工人进行正常工作时使用便携式仪器测量呼吸器对气溶胶颗粒的保护系数。便携式仪器，包括一组两个手持冷凝粒子计数器 (CPC) 和两个便携式气溶胶迁移谱仪 (PAMS)，使用一组两个参考扫描迁移率粒度仪 (SMPS) 进行了评估。便携式仪器安装在战术承重背心或背包上，并由测试对象在进行模拟工作场所活动时佩戴。模拟工作场所保护系数 (SWPF) 是使用暴露于三种不同稳态浓度水平氯化钠气溶胶的人类受试者测量的：低 (8x103 颗粒/cm3)、中等 (5x104 颗粒/cm3) 和高 (1x105 颗粒/cm3)。在开始对呼吸器进行 SWPF 测试之前，需要八名受试者通过定量适合性测试。每次 SWPF 测试均使用 5 次练习的方案进行，每次 3 分钟：(1) 站立时正常呼吸；(2) 弯腰；(3) 模拟实验室容器清洁运动；(4)原地行走缓慢；(5) 深呼吸。使用两套仪器（一套便携式仪器 {CPC 或 PAMS}，每套一套参考 SMPS）同时测量呼吸器内外的气溶胶浓度。SWPF 计算为外部和内部颗粒的比率。一般来说，使用手持式 CPC 测量的整体 SWPF 与使用参考 SMPS 测量的总体 SWPF 具有较好的一致性，其次是 PAMS。在模拟工作场所活动下，所有手持式 CPC、PAMS、和参考 SMPS 显示出类似的 GM SWPF 趋势，并且当模拟工作场所移动增加时，它们的 GM SWPF 下降。这项研究表明，在战术承重背心中安装两个手持式 CPC 或在背包中安装一个 PAMS 装置的新设计允许受试者在进行模拟工作场所活动时佩戴它。CPC 因其重量轻且没有重大仪器故障而显示出测量 SWPF 的潜力。