Lai C Y, Chen C C
Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan.
J Air Waste Manag Assoc. 2000 Apr;50(4):578-87. doi: 10.1080/10473289.2000.10464029.
The size range of airborne particles that is closely related to specific deposition regions in the human respiratory tract and excess lung burden of these deposited particles is associated with disease. Size-selective sampling, therefore, needs to be performed to assess the related health risks. Performance criteria applied to these samplers must be well characterized in order to provide accurate and reliable results. The PM10 samplers that have been used in place of the total suspended particulate samplers for the collection of ambient air particles are more relevant to potential inhalation hazards. In order to be certified, a PM10 sampler must meet reliable performance specifications, primarily the aerosol penetration test with liquid and solid particles in a wind tunnel (wind speeds of 2, 8, and 24 km/hr). This testing is intended to assure reasonable accuracy in aerosol measurements. However, the sampler performance under calm air conditions has not been well studied. In the present study, the sampling heads of three devices--the Harvard impactor, the Personal Environmental Monitor (PEM), and the Sierra Andersen model 241 dichotomous sampler PM10 inlet head--were tested for aerosol separation efficiency. With the consideration of bias and imprecision of the measurements, five specimens of each type of sampler were chosen for performance testing, repeating the tests 5 times for each specimen. An ultrasonic atomizing nozzle was used to nebulize potassium sodium tartrate tetrahydrate and dioctyl phthalate particles as the solid and liquid challenge aerosols, respectively. The aerosol number concentrations and size distributions upstream and downstream of the samplers were measured by using an aerosizer calibrated against a settling velocity chamber. The results showed that among the samplers tested, the dichotomous sampler PM10 inlet head had the best fit to the PM10 convention, while the other two samplers not only appeared to have a steeper separation-curve slope but also had significant particle bounce when challenged with solid particles. Analysis of variance also confirmed the superiority of the dichotomous samplers. Surface-coating with oil or grease greatly reduced the problem of particle bounce.
与人类呼吸道中特定沉积区域密切相关的空气传播颗粒大小范围以及这些沉积颗粒的肺部负担过重与疾病相关。因此，需要进行尺寸选择性采样以评估相关的健康风险。应用于这些采样器的性能标准必须得到充分表征，以便提供准确可靠的结果。已用于替代总悬浮颗粒物采样器来收集环境空气颗粒的PM10采样器与潜在的吸入危害更相关。为了获得认证，PM10采样器必须符合可靠的性能规格，主要是在风洞中对液体和固体颗粒进行气溶胶穿透测试（风速为2、8和24公里/小时）。该测试旨在确保气溶胶测量具有合理的准确性。然而，平静空气条件下采样器的性能尚未得到充分研究。在本研究中，对三种设备的采样头——哈佛冲击器、个人环境监测器（PEM）和塞拉·安德森241型二分采样器PM10入口头——进行了气溶胶分离效率测试。考虑到测量的偏差和不精确性，每种类型的采样器选择了五个样本进行性能测试，每个样本重复测试5次。使用超声雾化喷嘴分别雾化酒石酸钾钠四水合物和邻苯二甲酸二辛酯颗粒作为固体和液体挑战气溶胶。通过使用针对沉降速度室校准的气溶胶粒度分析仪测量采样器上游和下游的气溶胶数量浓度和粒径分布。结果表明，在所测试的采样器中，二分采样器PM10入口头最符合PM10标准，而其他两种采样器不仅分离曲线斜率似乎更陡，而且在受到固体颗粒挑战时还存在明显的颗粒反弹。方差分析也证实了二分采样器的优越性。用油或油脂进行表面涂层大大减少了颗粒反弹问题。
