Chen C C, Lai C Y, Shih T S, Yeh W Y
Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei.
Am Ind Hyg Assoc J. 1998 Nov;59(11):766-73. doi: 10.1080/15428119891010938.
Workplace aerosols must be sampled to assess the degree of health hazard caused by the particulate matter. By adjusting the sampling flow rate, most of the samplers can match the 50% cutoff size, but not the slope of the respirable convention defined by the American Conference of Governmental Industrial Hygienists, the International Organization for Standardization, and the European Committee for Standardization (CEN). Combinations of foams (or other porous material) of different nominal sizes (10-100 ppi) and thicknesses (5-35 mm) were employed to overcome this bias. A foam disk 25 mm in diameter was placed in an asbestos sampling cowl. Dioctylphthalate was the liquid test agent. An aerodynamic particle sizer and an Aerosizer were calibrated against a settling chamber and were employed to measure the aerosol number concentrations and size distributions upstream and downstream of the foams. The sampling efficiency data showed that the 50% cutoff size could be met for foams in series, but that the slope remained sharper than the new definition. Foams in parallel showed great flexibility and many of the parallel combinations flattened the slope, closer to that of the new international respirable convention. For instance, when the total flow rate is set at 10.1 L/min the aerosol penetration through foams in parallel (100 ppi, 20 mm thick, diameter 25 mm + 10 ppi, 20 mm thick, diameter 13 mm) nearly matched the new international standard for respirable fraction. This sampler can be further miniaturized for smaller sampling flow rates to fit the capacity of personal sampling pumps.
必须对工作场所的气溶胶进行采样，以评估颗粒物造成的健康危害程度。通过调整采样流速，大多数采样器可以匹配50%的截止粒径，但无法匹配美国政府工业卫生学家会议、国际标准化组织和欧洲标准化委员会（CEN）定义的可吸入颗粒物的斜率。采用不同标称尺寸（10 - 100目/英寸）和厚度（5 - 35毫米）的泡沫（或其他多孔材料）组合来克服这种偏差。将一个直径25毫米的泡沫圆盘放置在石棉采样罩中。邻苯二甲酸二辛酯为液体测试剂。使用空气动力学粒径分析仪和Aerosizer对沉降室进行校准，并用于测量泡沫上游和下游的气溶胶数量浓度和粒径分布。采样效率数据表明，串联的泡沫可以满足50%的截止粒径要求，但斜率仍比新定义的更陡。并联的泡沫表现出很大的灵活性，许多并联组合使斜率变平缓，更接近新的国际可吸入颗粒物定义。例如，当总流速设定为10.1升/分钟时，气溶胶通过并联泡沫（100目/英寸，20毫米厚，直径25毫米 + 10目/英寸，20毫米厚，直径13毫米）的穿透率几乎与新的国际可吸入颗粒物标准相符。这种采样器可以进一步小型化，以适应更小的采样流速，以匹配个人采样泵的容量。
