Ramirez Joel, O'Shaughnessy Patrick
a Department of Occupational and Environmental Health , College of Public Health, The University of Iowa , Iowa City , Iowa.
J Occup Environ Hyg. 2017 Feb;14(2):148-157. doi: 10.1080/15459624.2016.1237027.
The primary objective of this study was to compare the filter performance of a representative selection of uncertified dust masks relative to the filter performance of a set of NIOSH-approved N95 filtering face-piece respirators (FFRs). Five different models of commercially available dust masks were selected for this study. Filter penetration of new dust masks was evaluated against a sodium chloride aerosol. Breathing resistance (BR) of new dust masks and FFRs was then measured for 120 min while challenging the dust masks and FFRs with Arizona road dust (ARD) at 25°C and 30% relative humidity. Results demonstrated that a wide range of maximum filter penetration was observed among the dust masks tested in this study (3-75% at the most penetrating particle size (p < 0.001). The breathing resistances of the unused FFRs and dust masks did not vary greatly (8-13 mm HO) but were significantly different (p < 0.001). After dust loading there was a significant difference between the BR caused by the ARD dust layer on each FFR and dust mask. Microscopic analysis of the external layer of each dust mask and FFR suggests that different collection media in the external layer influences the development of the dust layer and therefore affects the increase in BR differently between the tested models. Two of the dust masks had penetration values < 5% and quality factors (0.26 and 0.33) comparable to those obtained for the two FFRs (0.23 and 0.31). However, the remaining three dust masks, those with penetration > 15%, had quality factors ranging between 0.04-0.15 primarily because their initial BR remained relatively high. These results indicate that some dust masks analysed during this research did not have an expected very low BR to compensate for their high penetration.
本研究的主要目的是比较一组未经认证的防尘口罩与一组美国国家职业安全与健康研究所（NIOSH）批准的N95过滤式面罩呼吸器（FFR）的过滤性能。本研究选择了五种不同型号的市售防尘口罩。针对氯化钠气雾剂评估了新防尘口罩的过滤穿透率。然后在25°C和30%相对湿度下，用亚利桑那道路灰尘（ARD）对防尘口罩和FFR进行测试，同时测量新防尘口罩和FFR的呼吸阻力（BR），持续120分钟。结果表明，在本研究测试的防尘口罩中观察到了广泛的最大过滤穿透率范围（在最易穿透粒径下为3 - 75%，p < 0.001）。未使用的FFR和防尘口罩的呼吸阻力差异不大（8 - 13 mm H₂O），但差异显著（p < 0.001）。加载灰尘后，每个FFR和防尘口罩上ARD灰尘层引起的BR存在显著差异。对每个防尘口罩和FFR外层的显微镜分析表明，外层不同的收集介质会影响灰尘层的形成，因此不同测试型号之间BR的增加受到不同影响。其中两款防尘口罩的穿透率值<5%，质量因子（分别为0.26和0.33）与两款FFR（分别为0.23和0.31）相当。然而，其余三款穿透率>15%的防尘口罩，其质量因子在0.04 - 0.15之间，主要是因为它们最初的BR仍然相对较高。这些结果表明，在本研究中分析的一些防尘口罩没有预期的非常低的BR来弥补其高穿透率。
