Evaluation of respirator filters for asbestos fibers
Evaluation of respirator filters for asbestos fibers
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DOI：
10.1080/15459620500444046
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发表时间：
2006-01-01
影响因子：
2
通讯作者：
Fan, BJ
中科院分区：
文献类型：
--
作者：
Cheng, YS;Holmes, TD;Fan, BJ
众所周知，纤维气雾剂具有与球形颗粒不同的空气动力学行为，通常带有更高的静电电荷。我们研究了滤芯的流量和装药状态对球形和纤维气溶胶穿透的影响。选择了四种口罩过滤器：两种用于被动口罩，一种用于电动口罩，一种是一次性口罩。使用非接触式电场静电场计测了口罩过滤器上的表面电荷。对滤芯进行了电荷中和前后的渗透试验。对口罩过滤器的表面电荷测量表明，一些过滤器，包括用于一次性口罩的过滤器，是带电的，以提高收集效率。只有高效的微粒空气过滤器对球形测试气雾剂和三种类型的石棉纤维都具有一致的性能。滤芯的表面电荷电势和流速似乎不影响这些过滤器的性能。与高效过滤器相比，当去除过滤器上的电势时，低效率过滤器和口罩的气溶胶穿透性能恶化。我们的数据还表明，在高温、高湿环境中，表面电荷减少，并在一周后消失。荷电一次性口罩过滤器中球形颗粒和纤维的沉积得到了增强。对于带电中和的低效率滤芯，石棉纤维可以穿透平均直径为0.3微米的球形颗粒。
Fiber aerosols are known to have different aerodynamic behaviors than spherical particles and usually carry higher electrostatic charges. We investigated the effects of flow rate and charge status of filter cartridges on the penetration of spherical and fiber aerosols. Four types of test respirator filters were selected: two for passive respirators, one for a powered respirator, and one disposable respirator Surface charges on respirator filters were determined using a noncontact field electrostatic field meter. Penetration tests were performed for filter cartridges before and after charge neutralization. The surface charge measurements on the respirator filters showed that some filters, including those used in disposable face masks, are charged to enhance the collection efficiency. Only high efficiency particulate air filters performed consistently for both spherical test aerosols and the three types of asbestos fibers. The surface charge potential of filter cartridges and flow rate did not appear to affect the performance of these filters. In contrast to the high-efficiency filters, the aerosol penetration performance of low-efficiency filters and face masks deteriorated when the charge potential on the filter was removed. Our data also showed that the surface charges decreased in a high temperature, high-humidity environment and disappeared after I week. Deposition of spherical particles and fibers in the charged disposable facemask filter was enhanced. For charged neutralized, low-efficiency filter cartridges, asbestos fibers may penetrate more than spherical particles with a mean particle size of 0.3 mu m diameter.