Carbon nanotubes (CNTs) are currently used in numerous industrial and biomedical applications. Recent studies suggest that workers may be at risk of adverse health effects if they are exposed to CNTs. A National Institute for Occupational Safety and Health (NIOSH) survey of the carbonaceous nanomaterial industry found that 77% of the companies used respiratory protection. Elastomeric half-mask respirators and filtering facepiece respirators (FFRs) are commonly used. Although numerous respirator filtration studies have been done with surrogate engineered nanoparticles, such as sodium chloride, penetration data from engineered nanoparticles such as CNTs are lacking. The aims of this study were to develop a new CNT aerosol respirator testing system and to determine multi-walled CNT (MWCNT) penetration through FFRs. A custom-designed CNT aerosol respirator testing system (CNT-ARTS) was developed which was capable of producing a sufficient amount of airborne MWCNTs for testing of high efficiency FFRs. The size distribution of airborne MWCNTs was 20-10,000 nm, with 99% of the particles between 25 and 2840 nm. The count median diameter (CMD) was 209 nm with a geometric standard deviation (GSD) of 1.98. This particle size range is similar to those found in some work environments (particles ≤6000 nm). The penetration of MWCNTs through six tested FFR models at two constant flow rates of 30 and 85 LPM was determined. Penetration at 85 LPM (0.58-2.04% for N95, 0.15-0.32% for N99, and 0.007-0.009% for P100 FFRs) was greater compared with the values at 30 LPM (0.28-1.79% for N95, 0.10-0.24% for N99, and 0.005-0.006% for P100 FFRs). The most penetrating particle size through all six tested FFR models was found to be in the range of 25-130 nm and 35-200 nm for the 30-LPM and 85-LPM flow rates, respectively.

中文翻译：

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开发一种新的测试系统来确定多壁碳纳米管通过过滤式面罩呼吸器的渗透

碳纳米管 (CNT) 目前用于许多工业和生物医学应用。最近的研究表明，如果工人接触碳纳米管，他们可能面临对健康不利的风险。美国国家职业安全与健康研究所 (NIOSH) 对碳质纳米材料行业的一项调查发现，77% 的公司使用了呼吸防护装置。通常使用弹性半面罩呼吸器和过滤式面罩呼吸器 (FFR)。尽管已经对替代工程纳米粒子（例如氯化钠）进行了大量呼吸器过滤研究，但缺乏工程纳米粒子（例如 CNT）的渗透数据。本研究的目的是开发一种新的 CNT 气溶胶呼吸器测试系统，并确定多壁 CNT (MWCNT) 对 FFR 的渗透。开发了一种定制设计的 CNT 气溶胶呼吸器测试系统 (CNT-ARTS)，该系统能够产生足够数量的空气传播 MWCNT，用于测试高效 FFR。空气中 MWCNTs 的尺寸分布为 20-10,000 nm，99% 的颗粒在 25-2840 nm 之间。计数中值直径 (CMD) 为 209 nm，几何标准偏差 (GSD) 为 1.98。该粒径范围类似于在某些工作环境中发现的粒径范围（颗粒≤6000 nm）。确定了 MWCNT 在 30 和 85 LPM 的两个恒定流速下通过六个测试 FFR 模型的渗透。85 LPM 时的渗透率（N95 为 0.58-2.04%，N99 为 0.15-0.32%，P100 FFR 为 0.007-0.009%）与 30 LPM 时的值（N95 为 0.28-1.79%，0.24% 为 0.24%）相比更大N99，P100 FFR 为 0.005-0.006%）。